qos_b8

© Alcatel University - 8AS 90200 1424 VH ZZA Ed.02 .1

© Alcatel University - 8AS 90200 1424 VT ZZA Ed.021.1

Introduction to

QUALITY OF SERVICE and TRAFFIC LOAD

MONITORING

BSS release B8

B8

© Alcatel University - 8AS 90200 1424 VH ZZA Ed.02 Page 1.2

1.2

PROGRAM

1 INTRODUCTION

2 GLOBAL INDICATORS

3 DETAILED INDICATORS

4 HANDOVER INDICATORS

5 DIRECTED RETRY INDICATORS

6 RADIO MEASUREMENT STATISTICS INDICATORS

7 TRAFFIC INDICATORS

B8



1 INTRODUCTION


1.4

1 IntroductionSession presentation

� Objective: to be able to explain what is QoS and Traffic Load monitoring of the BSS and what are the information sources available for that purpose

� Program:

1.1 Monitoring the QoS of the BSS

1.2 Monitoring the Traffic Load of the BSS

1.3 Information sources available

1.4 Introduction to K1205 PC emulation



1 INTRODUCTION

1.1 Monitoring the QoS of the BSS


1.6

1.1 Monitoring the QoS of the BSSDefinition

� ”Monitor" "network" "quality"

�monitor = measure or ensure?

� network = BSS? BSS+NSS? BSS+NSS+PSTN …

� quality = service (end-user) and/or system (technical)

� But also detect, localize, diagnose outages

� detect (decide according to thresholds)

� localize (which cell, BSC, etc.)

� diagnose: radio, BSS, TC problems


1.7

1.1 Monitoring the QoS of the BSSUsage

QoS ResultsQoS Results

Management•network monitoring•comparison with competitor•comparison of manufacturers•contractual requirement: licence•quality responsible

Management•network monitoring•comparison with competitor•comparison of manufacturers•contractual requirement: licence•quality responsible

Radio optimization•cell radio quality survey•HO quality monitoring•assessment of tuning efficiency

Radio optimization•cell radio quality survey•HO quality monitoring•assessment of tuning efficiency

BSS maintenance•cell/BSC/TC problem detectionBSS maintenance•cell/BSC/TC problem detection

� 3 usages of QoS data ⇒ 3 levels of QoS reports:

1. Management team: has to compare Network QoS with competitors' one and to plan Network evolutions.

⇒ needs to have a general view of the Network QoS on a monthly (and sometimes weekly) basis.

2. Radio Optimization team: has to detect bad QoS areas in the network and to implement and assess modifications for QoS improvement.

⇒ needs to have a detailed status and evolution of the QoS at BSS and cell (and sometimes TRX) levels on a weekly, daily (and sometimes hourly) basis.

3. Supervision and Maintenance team: has to detect dramatic QoS degradations and identify the responsible Network Element (and if possible component).

⇒ needs to have the most detailed status of QoS at cell and TRX levels on an hourly basis.



1 INTRODUCTION

1.2 Monitoring the Traffic Load of the BSS


1.9

1.2 Monitoring the Traffic Load of the BSS Definition

� Measure the "quantity" of traffic handled by:

� the network

� the BSCs

� the cells

� Analyze traffic characteristics

� call, handover, location update, etc.

� As input for dimensioning/architecture team

� Traffic characteristics used as a "call mix" to dimension or re-dimension the network will be developed in the section Monitoring the Traffic Load of the BSS.



1 INTRODUCTION

1.3 Information sources available


1.11

1.3 Information sources available Observation means

� DIFFERENT WAYS TO OBSERVE/MEASURE the GSM network

External Interface AnalysisExternal Interface AnalysisExternal Interface AnalysisExternal Interface AnalysisA interface: MSC/TC-BSCAbis interface: BSC/BTSAir MS/BTS

Counter browser

OMC CountersOMC CountersOMC CountersOMC CountersBSC(NSS)

Tektronix K1205

Gnnettest MPAW&G NPA

� QoS data can be built-up from different and complementary kinds of information sources.

� Usually post-processing applications will build up QoS indicators from:

� OMC-R counters provided by the BSS system itself.

� Signaling messages provided by a protocol acquisition tool on the different interfaces handled by the BSS: Air, Abis, A (or Ater).

Abis

A

MSC/VLR

AbisBSC TC

BTS

Ater

Air

SACCH RSL N7 N7

drive test tool protocol analyzer

MS


1.12

1.3 Information sources available A interface trace

INFORMATION SOURCE: EXTERNAL INTERFACE "A"

� Capture/decode signaling between MSC and BSC-TC (A or AterMUX)

with "protocol analyzer" (Wandel, Tektronix, Gnnettest, etc.)

+ GSM standard, can be used for arbitrage between manufacturers

+ Complete information (message contents, time-stamp)

+ Possible detection of User/MS/BSS/TC/NSS problems

- High cost of equipment

- Time consuming, "post mortem" (installation of tool, file analysis)

- Important expertise needed for analysis

- Low coverage (K1103/MA10: 8 COCs, K1205/MPA: 32 COCs maximum!)

- Large amount of data (>> 10 Mbytes /hour/BSC)

� The main advantage of the A interface is to allow the detection of Call Setup failures either due to the User or to the NSS (or PSTN).

� Some typical user failure causes are: Some typical NSS failure causes are:

IMSI Unknown in VLR Temporary FailureIMSI Unknown in HLR Resource UnavailableIMEI Not Accepted Switching Equipment CongestionPLMN Not Allowed Normal UnspecifiedService Option Not Supported Recovery on Timer ExpiryRequested Service Not Supported Call Reject Unassigned Number InterworkingOperator Determined Barring Protocol ErrorUser Alerting Network FailureFacility Not Subscribed CongestionNo Route to DestinationNormal Call ClearingUser BusyInvalid Number FormatCall RejectInterworkingNormal Unspecified

� CAUTION: In order to assess the QoS of a BSS or some cells of a BSS, all N7 links between this BSC and the MSC must be traced. Indeed, as the N7 signaling load is spread over all N7 links, signaling messages relating to one call can be conveyed onany of the active N7 links.

� K1103 protocol analyzer can trace up to 8 COCs at the same time but on maximum 4 PCM physical links.

� K1205 protocol analyzer can trace up to 32 COCs at the same time but on maximum 16 PCM physical links.


1.13

1.3 Information sources available Example of trace

� on a K1205 protocol analyzer


1.14

1.3 Information sources available Abis interface trace

INFORMATION SOURCE: EXTERNAL INTERFACE "Abis"

� Capture/decode signaling between BSC and BTS with "protocol analyzer" (Wandel, Tektronix, Gnnettest, etc.)

� Complete information (message contents, time-stamp)

� Possible detection of User/MS/BSS/TC/NSS problems

� Complete radio information thanks to measurement messages

� Downlink and uplink

– High cost of equipment

– Time consuming, "post mortem" (installation of tool, file analysis)

– Important expertise needed for analysis

– Very low coverage (A few RSLs, a few cell(s))

– Very large amount of data (>> 10 Mbytes/hour/BTS)

� The main advantage of the Abis trace is to allow a detailed and precise assessment of the radio quality of a cell at TRX level. Both DownLink and UpLink paths can be observed and compared.

� BUT from B7 release, the Radio Measurement Statistics (RMS) feature implemented in the BSS provides a good level of information allowing to reduce the number of Abis traces to be done for radio network optimization.


1.15

1.3 Information sources available Air interface trace

INFORMATION SOURCE: EXTERNAL INTERFACE "Air"

� Use trace MS to capture signaling and signal characteristics

� Give precise location (x,y) of problems

� Give downlink radio information

� Only way to localize a lack of coverage

� Only way to monitor competitor

– High cost of equipment

– Very time-consuming

– Difficulty to perform a lot of calls

� number of samples insufficient

� only a few streets

– No uplink

� The main advantage of the Air trace is to associate a radio quality measurement to a given geographical area of the network.

� Even if in release B7 the RMS feature will allow to assess the radio quality as perceived by the end user, no location of the radio problems is provided through the RMS.


1.16

1.3 Information sources available Performance Measurement counters

SUB-SYSTEM COUNTERS

� Counts events seen by sub-system, value reported periodically (1 hour)

� Low cost: collected directly at OMC

� Compact data: possibility to store counters for a complete network

– Raw information, having to be consolidated to be understandable

– Manufacturer's dependent: questionable/difficult to compare

– Weak to analyze other sub-systems

� The main advantage of the BSS counters is to provide easily QoS data for permanent QoS monitoring.


1.17

1.3 Information sources available Exercise

� Training exercise

� Draw the BSS PM counters flow on the chart

� In which sub-system are the BSS QoS indicators computed and stored?

BSC

BSC

BSC

OMC-R

OMC-R OMC-R

NPA

� NPA is the Alcatel product for the Network Performance Analysis of the Alcatel BSS.

� RNO is the Alcatel product for the Radio Network Optimization of the Alcatel BSS.


1.18

1.3 Information sources available BSS counters

BSS COUNTERS

� Combined into significant formulae: indicators

� Used to monitor BSS network quality

� Over a complete network, with breakdown per cell/BSC

� SPECIFIC DRAWBACK

� NSS/PSTN/MS/USER problems not seen

� As BSS PM counters are defined in order to provide information to assess the QoS of the BSS and help to detect BSS misbehavior, there is no way to identify QoS problems due to NSS, PSTN or User.


1.19

1.3 Information sources available NSS counters

NSS COUNTERS

� Combined into significant formulas: indicators

� Used to monitor NSS network quality

� Over a complete network, with breakdown per BSC (maximum)

� SPECIFIC DRAWBACKS

� BSS problems usually not precisely identified

� No breakdown per cell

� The NSS QoS is provided through NSS PM counters and indicators. It is out of the scope ot this training course.


1.20

1.3 Information sources available ALCATEL BSS counters

INFORMATION SOURCES: BSS Counters

In order to provide the operators with an easy and cost-effective way to monitor their network and carried traffic, BSS manufacturers have implemented specific software features, called performance management.

The principle is to count for a given duration called granularity period (typically 1 hour) pre-defined events occurring on the Abis or A interface, or internally. These counters are stored for each duration, with breakdown per network component (i.e. cell).

In BSS B8, about 970 counters are available (without GPRS).

In Alcatel BSS (except GPRS), counters

are computed by BSC, based mainly on

Abis messages.

Every reporting period, counters values are sent to the OMC-R for storage.

In B7 159 ALCATEL counters are reported to the OMC-R permanently every PM granularity period:

�3 per cell adjacency

�20 per TRX

�127 per cell

�4 per N7 link

�5 per BSC

⇒ millions of counters are collected every day

� Alcatel has chosen to implement PM counters in the BSC and to increment them mostly on Abis interface signaling messages.

� Other suppliers may have chosen to increment them on A interface signaling messages or to implement them in the BTS.

� Therefore caution should be taken when interpreting QoS indicators value since some discrepancies may be observed due tothese possible choices.


1.21

1.3 Information sources available Example of BSS counter

� MC718: counter number

� NB_TCH_NOR_ASS_SUCC_TRX: counter name

� Cumulative: method of computation

� Type 110: Overview measurements: BSS PM measurement type to which the counter

belongs

� Measured object: minimum object level for which the counter is provided: TRX or CELL or

BSC or N7 LINK or X25 LINK etc.

Counter

Example

� All counters are described in the "PM counters and indicators" document whose B7 reference is xxxxxxxxx.


1.22

1.3 Information sources available BSS counter characteristics

Collection mechanism

� Cumulative

� The counter is incremented at the occurence of a specific event

� Abis or A message, or internal event

� At the end of a collection period, the result is the sum of the events

� Inspection

� Every 20 or 10 seconds, a task quantifies an internal resource status (usually a table)

� At the end of a collection period, the result is the mean value

� Observation

� Set of recorded information about a telecom procedure (handover,

channel release, UL & DL measurements reporting)

� Main counters are of cumulative type.

� Inspection counters are of gauge type.

� Observation counters are grouped in a Performance Measurement record associated to a particular GSM BSS telecom procedure: SDCCH channel seizure, TCH channel seizure, internal handover, etc.


1.23

BSS Performance Measurement types

1.3 Information sources available BSS PM types

N° Type Name Type definition

1 Traffic Measurement Set of counters related to the traffic evaluation per telecom procedure

2 Resource Availability Measurement Set of counters related to the availability of the CCCH, SDCCH, or TCH channels

3 CCCH channel resource usage measurements Set of counters related to the usage of CCCH channel (PCH, AGCH, RACH)

4 SDCCH channel resource usage measurements Set of counters related to the usage of SDCCH channel

5 TCH channel resource usage measurements Set of counters related to the usage of TCH channel

6 TCH Handover Measurements Set of counters related to the TCH handover procedure

7 LAPD Measurement Set of counters related to the LapD logical links

8 X.25 Measurement Set of counters related to the X25 links OMC-BSC

9 N7 Measurement Set of counters related to the N7 Signaling Links

10 SDCCH Observations Observation counters on SDCCH channels allocated

11 TCH measurements observations Observation counters on 08.58 MEASUREMENT REPORT for a TCH

12 Internal Handover Observations Observation counters on internal intra-cell or inter-cell SDCCH or TCH handover

13 Incoming External Handover Observations Observation counters on incoming external SDCCH or TCH handover

14 Outgoing External Handover Observations Observation counters on outgoing external SDCCH or TCH handover

15 TCH Observation Observation counters on TCH channel allocated

18 A Interface measurements different causes of 08.08 CLEAR REQUEST and 08.08 ASSIGNMENT FAILURE

19 SMS PP Measurements Set of counters related to Short Message Service Point to Point

25 SCCP Measurements Set of counters related to SCCP Layer of the N7 signaling Links

26 TCH outgoing Handover per adjency Set of counters related to outgoing TCH handover provided per adjency

27 TCH incoming Handover per adjency Set of counters related to incoming TCH handover provided per adjency

28 SDCCH Handover Set of counter related to the SDCCH handover procedure

29 Directed Retry measurements Set of counter related to the directed retry handover procedure

30 SMS CB Measurements Set of counters related to Short Message Service Cell Broadcast

31 Radio Measurement Statistics Set of counters providing radio quality measurements for TRX/Cell

32 Change of frequency band measurements Set of counters related to handovers including a change of TCH Frequency band

110 Overview measurements Set of key counters allowing to access Quality of Service of a given Cell/BSC/Network

180 Traffic Flow measurements Set of counters related to incoming inter-cell SDCCH/TCH handover performed

per (servin a cell, target cell) adjency

B8

NewB8

� BSS Performance Measurement types (PM types) are split into two categories:

� standard types (7, 8, 9, 18, 19, 25, 28, 29, 30, 31, 32,110, 180)

� detailed types (1, 2, 3, 4, 5, 6, 10, 11, 12, 13, 14, 15, 26, 27)

� The most important types for QoS monitoring and Radio Network Optimization are in bold.

� A standard PM type can be activated for the whole network. It means that the related counters are reported for all the Network Elements they are implemented on (TRX, CELL, N7 link, X25 link, LAPD link, Adjacency).

� A detailed PM type can be activated only on a sub-set of the network. It means that the related counters are reported only for a limited number of Network Elements:

� 40 cells per BSS for PM types 1, 2, 3, 4, 5, 6, 26, 29

� 15 cells per BSS for PM types 10, 12, 13, 14, 15

� 1 cell per BSS for PM types 11, 27

� Counter numbering rules:

� Cyz: cumulative or inspection counters in PM types 1, 2, 3, 4, 5, 6, 18, 19, 25, 26, 27, 28, 29, 30, 32, 180

� Ly.z: cumulative counters in PM type 7 (L stands for LAPD link)

� Xy.z: cumulative counters in PM type 8 (X stands for X25 link)

� Ny.z: cumulative counters in PM type 9 (N stands for N7 link)

� Syz: observation counters in PM type 10 (S stands for SDCCH)

� Ryz:: observation counters in PM type 11 (R stands for Radio measurements)

� HOyz: observation counters in PM type 12, 13, 14 (HO stands for HandOver)

� Tyz: observation counters in PM type 15 (T stands for TCH)

� RMSyz: cumulative counters in PM type 31 (RMS stands for Radio Measurement Statistics)

� MCyz or MNy.z: cumulative counters in PM type 110 (M stands for Major)


1.24

1.3 Information sources available Observation means

� Training exercise: find the best source of information

Observation to Observation to Observation to Observation to be be be be donedonedonedone : : : : best sourcebest sourcebest sourcebest source whywhywhywhy

overall radio overall radio overall radio overall radio quality of 1 quality of 1 quality of 1 quality of 1 cellcellcellcell Counters Type 31 : RMS

monitor user monitor user monitor user monitor user failuresfailuresfailuresfailures

get get get get average network average network average network average network qualityqualityqualityquality

localise localise localise localise precise location of a radio precise location of a radio precise location of a radio precise location of a radio pbpbpbpb

identify identify identify identify abnormal abnormal abnormal abnormal cells in a networkcells in a networkcells in a networkcells in a network

history of network history of network history of network history of network quality for quality for quality for quality for several several several several weeksweeksweeksweeks

compare networks compare networks compare networks compare networks qualityqualityqualityquality

discriminate discriminate discriminate discriminate problems problems problems problems between BSS/NSS. BSSbetween BSS/NSS. BSSbetween BSS/NSS. BSSbetween BSS/NSS. BSSand NSS and NSS and NSS and NSS coming coming coming coming from from from from different different different different providersprovidersprovidersproviders

make make make make statistics about statistics about statistics about statistics about complete networkcomplete networkcomplete networkcomplete network

In a building, one In a building, one In a building, one In a building, one is is is is thinking thinking thinking thinking that an that an that an that an elevator elevator elevator elevator isisisisinducing PCM trouble, how to inducing PCM trouble, how to inducing PCM trouble, how to inducing PCM trouble, how to confirm ?confirm ?confirm ?confirm ?Identify Identify Identify Identify potential potential potential potential interfering interfering interfering interfering cells of 1 cellcells of 1 cellcells of 1 cellcells of 1 cell



1 INTRODUCTION

1.4 Introduction to K1205 PC emulation


1.26

1.4 Introduction to K1205 PC emulation Usage

INTRODUCTION TO K1205 PC EMULATION

� The trace done with K1205 can be read:

�Directly on K1205 itself

�On any PC Windows NT with dedicated emulation software

� Practical exercises will be done during the course using this software

� The following slides and exercises are here to teach you the basic skill needed to operate the tool for A Interface decoding


1.27

1.4 Introduction to K1205 PC emulation Scenarios screen

To select binary trace file and

decoding protocol

To select binary trace file and

decoding protocol

To enter in monitoring mode

To enter in monitoring mode

1. Start the K1205 Protocol Tester application.

2. In the Recording File box: click on the Open button and select the "PAIB29.rec" file.

3. Select all displayed N7 logical links (corresponding to 4 PCMs in this case).

4. Click on the Browse button and select gsm2_A.stk in the gsm2 sub-directory (corresponding to the GSM Phase 2 A interface protocol stack).

5. Click on OK.

6. Click on the Monitor box to display the content of the recorded trace.


1.28

1.4 Introduction to K1205 PC emulation Monitor screen

1 line / message1 line / message

Full decoding of selected message

Full decoding of selected message

Message content in hexadecimal

Message content in hexadecimal

To extract 1 callTo extract 1 call


1.29

1.4 Introduction to K1205 PC emulation Filter configuration

HOW TO EXTRACT A CALL ON THE INTERFACE

1) Filter out paging message

� Keep only BSSAP and DTAP

� Except PAGING

2) Use SCCP references

� 1 on any message

� The 2 on CC message

ANNEX 3

� ANNEX 3 introduces some basics on the GSM protocol layers that will be traced for the A interface analysis.

� At call setup, the first signaling message on the A interface is sent by the BSC to the MSC in order to set up a logical link (called SCCP connection) between the BSS and the NSS.

� Both BSS and NSS entities choose a unique reference which has to be used by the other party to identify the SCCP connection on which the messages are conveyed. Both BSS reference (xxx) and NSS reference (yyy) are exchanged during the SCCP Connection Request and Connection Confirm phases. After that only the reference of the other party is used.

BSC MSC

SCCP CR

SLR= xxx ; DLR= none

SCCP CC

SLR= yyy ; DLR= xxx

msg i

SLR= none ; DLR= yyy

msg j

SLR= none ; DLR= xxx

Radio Link Establishment


1.30

1.4 Introduction to K1205 PC emulation Call extraction

Then

� Click on the Filter button and filter out all protocol layers and messages except:

� all DTAP messages,

� all BSSMAP messages except "Paging”,

� SCCP CR (Connection Request) and CC (Connection Confirm) messages.


1.31

PRACTICAL EXERCICE

� Use the tool to extract a few calls from file PAIB29.REC

1.4 Introduction to K1205 PC emulation Exercise



2 GLOBAL INDICATORS


1.33

2 Global indicatorsSession presentation

� Objective: to be able to explain what is a Global indicator and what are the main BSS indicators regarding GSM services provided by the Alcatel BSS

� Program:

2.1 Indicators definition

2.2 Methodological precautions

2.3 Typical call failures

2.4 Description of global indicators

2.5 Traps and restrictions of global indicators

2.6 Global indicators interpretation



2 GLOBAL INDICATORS

2.1 Indicators definition


1.35

2.1 Indicators definitionGlobal / detailed

BSS INDICATORS DEFINITION (Alcatel)

� Numerical data providing information about network performance regarding:

� The complete network: GLOBAL indicator

� An element of the network: DETAILED indicator

�TS/TRX/CELL/BTS/BSC/TC

� A formulae of several counter(s)

� Counters vs. Indicators

� Counters: provided by the BSS equipments

� Indicators: computed by BSS Monitoring equipments

� The indicators computation can be performed from several counters or by a simple counter mapping.

� Example:

� call drop rate = Call Drop nb / Call nb = f(counters)

� call drop = Call drop nb = 1 counter


1.36

2.1 Indicators definitionGlobal

GLOBAL INDICATORS

� Measure the performance of the complete network

� Analyzed according their trend and values

� Usually every day (week, month)

� Compared with:

� Competitor results if available

� Contractual requirements

� Internal quality requirements


1.37

2.1 Indicators definitionThresholds

EXAMPLE: Thresholds on Call Drop Rate indicator

Weekly CDR "GSM"

0,00%

0,50%

1,00%

1,50%

2,00%

2,50%

3,00%

3,50%

1 5 9

13

17

21

25

29

33

37

41

45

week number

CD

R

weekly call drop rate

contractual call drop rate

quality CDR

Weekly CDR "GSM"

0,00%

0,50%

1,00%

1,50%

2,00%

2,50%

3,00%

3,50%

1 5 9

13

17

21

25

29

33

37

41

45

week number

CD

R

weekly call drop rate

contractual call drop rate

quality CDR

� The Call Drop rate at network level has to compared to:

� Contractual threshold: can be requested by the operator management to the operational radio team, can be requested by the operator to the provider on swap or network installation

� Quality threshold: fixed internally by radio team management.

� Quality thresholds are usually more tight than contractual ones.


1.38

2.1 Indicators definitionExercise

TRAINING EXERCISE: GLOBAL OR NOT

INDICATOR DESCRIPTION G ?

average of call setup success rate for the network Yes

rate of call lost due to radio pb on cell CI=14, LAC=234 No

call drop rate in your capital

call drop rate of the cell covering a specific buidling

% of HO with the cause better cell (among other causes) for the network

average rate of TCHs dropped for all TRXs of the network carrying 1 SDCCH8

rate of SDCCHs dropped on TRX1 of cell 12,24

call success of 1 PLMN

% of cells being congested today



2 GLOBAL INDICATORS

2.2 Methodological precautions


1.40

2.2 Methodological precautions Objective

METHODOLOGICAL PRECAUTIONS

� Avoid typical errors regarding indicators interpretation


1.41

A good value for a global indicator

⇓⇓⇓⇓All network components are OK regarding this indicator

Example

� A global call drop rate of 1%

� Can hide some cells with 10 % of call drop rate

2.2 Methodological precautions Global indicator value


1.42

2.2 Methodological precautions Network Element aggregation

� THE AVERAGE VALUE OF AN INDICATOR FOR A NETWORK

� IS NOT THE AVERAGE OF CELL RESULTS (or any sub-part of it)

� BUT THE AVERAGE WEIGHTED BY THE TRAFFIC

number of calls number of call drop call drop rate

cell 1 390 8 2,10%

cell 2 546 29 5,25%

cell 3 637 20 3,10%

cell 4 1029 12 1,14%

cell 5 536 3 0,50%

cell 6 2 1 50,00%

cell 7 3 1 33,00%

cell 8 210 4 2,11%

cell 9 432 5 1,20%

cell 10 321 4 1,11%

average of cell results 9,95%

total nb of drop/total number of calls 2,10%


1.43

2.2 Methodological precautions Global indicator validity

� To be reliable, an indicator must be based on a sufficient number of events

� Estimation theory (MR.Spiegel, « theory and problems of probability and statistics »,

SCHAUM):

� if « p » is the probability of success for a complete population

� if one is measuring the probability P based on a sample of size « N »

� There is a probability of 95 % that p is between P +/- 1.96*[(p*(1-p))/n] 0.5

� Example: for p = 90 % and N = 100 => [ 84,12% ; 95,88% ]

� This law cannot be used directly for indicators (an hourly indicator is not based on a random sample), but it is giving a rough estimate of level of confidence one can apply regarding the size of the sample

� If a sample (number of calls) is too small, one can take it for a longer duration

� On Alcatel QoS monitoring tool (MPM application on OMC-R, NPA or RNO), NEs (BSS, Cell or TRX) are highlighted with bad QoS indicator value if enough corresponding events have been observed (called Validity threshold).

� Examples:

� Cells with bad Call Drop rate will be highlighted if CDR > CDR_threshold and if the Number of Calls is greater than the CDR Validity threshold.

� Cells with bad Outgoing handover success rate will be highlighted if OHOSUR > OHOSUR_threshold and if the Number of Outgoing Handovers is greater than the OHO Validity threshold.


1.44

2.2 Methodological precautions Time period aggregation

� Take care of data consolidation

� Example:

� Mean cell congestion rate during busy hour

� Weighted average of cell congestion at the busy hour of the network?

� Weighted average of cell congestion rate for its specific busy hour?

� (definition of busy hour?)

� Usually:

� Cell Busy Hour = hour of the day where max TCH traffic (in erlang) is observed.

� BSC Busy Hour = hour of the day where max TCH traffic (as the sum of the TCH traffic of all cells of the BSS) is observed.


1.45

2.2 Methodological precautions Exercise

METHODOLOGICAL PRECAUTION: Training exercise

INDICATORINDICATORINDICATORINDICATOR SampleSampleSampleSample((((callscallscallscalls))))

conclusionconclusionconclusionconclusion OK ?OK ?OK ?OK ?

call drop = 0.9% incall drop = 0.9% incall drop = 0.9% incall drop = 0.9% in youryouryouryour countrycountrycountrycountry 2456435 all the cells have a good call drop NOK

callcallcallcall setup successsetup successsetup successsetup success forforforfor cellcellcellcell 15, 145 = 99,5%15, 145 = 99,5%15, 145 = 99,5%15, 145 = 99,5% 2315 there is a good call setup success rate for

15,145In Paris : 2500In Paris : 2500In Paris : 2500In Paris : 2500 cells withcells withcells withcells with 95% of call95% of call95% of call95% of call setupsetupsetupsetupsuccesssuccesssuccesssuccessIn theIn theIn theIn the restrestrestrest of France : 5000of France : 5000of France : 5000of France : 5000 cells withcells withcells withcells with98%98%98%98%

3267872for France

In France, call setup success = 97 %

call drop for BSS call drop for BSS call drop for BSS call drop for BSS «««« BSS_1BSS_1BSS_1BSS_1 »»»» = 1%= 1%= 1%= 1% 4500 the call drop for BSS_1 is good

call drop forcall drop forcall drop forcall drop for cellcellcellcell 156;13 = 5%156;13 = 5%156;13 = 5%156;13 = 5% 215 cell 156;13 has certainly a trouble

for BSS 1, call drop of 2,0%for BSS 1, call drop of 2,0%for BSS 1, call drop of 2,0%for BSS 1, call drop of 2,0%for BSS 2, call drop of 3,0%for BSS 2, call drop of 3,0%for BSS 2, call drop of 3,0%for BSS 2, call drop of 3,0%

40002000

LA = BSS1 + BSS2 has a call drop of 2,3 %

MSC MSC MSC MSC «««« StadiumStadiumStadiumStadium »»»» has a callhas a callhas a callhas a call setup successsetup successsetup successsetup success ofofofof95 %95 %95 %95 %

15346 BSS1 belonging to MSC Stadium has a call setupsuccess of 95¨%



2 GLOBAL INDICATORS

2.3 Typical call failures


1.47

2.3 Typical call failures Objective

� Description of the main call success and failures cases, with

� Main specific counters

� Main protocol timers

� Diagnose the main case of failures on A interface traces using K1205 emulation software


1.48

2.3 Typical call failures Call Setup phasing

4 stages for a call establishment, 2 for a location update

� Radio link establishment

� "SDCCH phase"

then only for "Circuit Switch call"

� TCH assignment

� "Alerting/connection" phase

Each phase has a specific utility and weaknesses


1.49

2.3 Typical call failures Radio Link Establishment - OC success

Originated Call: RLE success case

� T3101: guard timer for SDCCH allocation (Default: 3 seconds)

� CR/CC are used to exchange SCCP references� Any further message related to this call will have one (or 2) of these 2 references� K1205 can extract the call using these references (SLR, DLR!!)

MS BTS BSC MSC

CHANNEL REQUEST-------------(RACH)------------> CHANNEL REQUIRED

----------------------------------------------> MC8CCHANNEL ACTIVATION (SDCCH)

<---------------------------------------------- MC148CHANNEL ACTIVATION ACK

---------------------------------------------->IMMEDIATE ASSIGN COMMAND

IMMEDIATE ASSIGN <---------------------------------------------- start T3101MC8B

<------------(AGCH)-------------SABM (L3 info)

-------------(SDCCH)-----------> ESTABLISH IND (L3 info)

UA (L3 info) ----------------------------------------------> stop T3101<-----------(SDCCH)------------- MC02

CR (COMPLETE L3 INFO)---------------------------------->

CC

<----------------------------------

B8

NewB8

Specific case of Call establishment

failure:

Loss of messages due to LapD congestioncan be follow with a new counter (see notes)LapD

� The SDCCH resource allocation is performed by the BSC. Once allocated the SDCCH channel is activated by the BTS on BSC request.

� T3101 is the guard timer for the SDCCH access from the MS. The Default value is 3 seconds.

� MC8C counts the number of Channels Required received from the MS in a cell.

� MC148 counts the number of SDCCH channels activated (therefore allocated) in a cell.

� MC8B counts the number of time an MS is commanded to access an SDCCH channel in a cell.

� MC02 counts the number of MSs which have successfully accessed an SDCCH in a cell as part of a Mobile Originating (MO) call.

� The SCCP Connection Request message is conveyed on an A interface PCM timeslot chosen by the BSC (called COC).

� The SCCP Connection Confirm message is conveyed on a COC chosen by the MSC which can be located on a different PCM than the one of the COC used by the BSC to send signaling messages to the MSC.

� Take care than, when the BSC is congested on the downlink, some messages are discarded. This may result for example in call establishment failures, loss of paging messages or delay in handover procedures.

� From B8

� A new LapD counter that indicates the time a LapD link is congested is created to analyze the cause of a degraded quality of service. This counter is implemented in type 7 and thus only be available in a detailed measurement campaign.

� Counter: L1.18: TIME_LAPD_CONG

� Definition: Time in seconds during which the LapD link is congested in transmission in the BSC.


1.50

2.3 Typical call failures Radio Link Establishment - TC success

Terminated Call: RLE success case

MS BTS BSC MSC

PAGINGPAGING COMMAND <----------------------------------

PAGING REQUEST <---------------------------------------------- start T3113<-------------(PCH)-------------- MC8A





IMMEDIATE ASSIGN <---------------------------------------------- Start T3101<------------(AGCH)------------- MC8B

SABM (PAGING RESP)-------------(SDCCH)-----------> ESTABLISH IND (PAGING RESP)

UA (PAGING RESP) ----------------------------------------------> Stop T3101<-----------(SDCCH)------------- MC01

CR (COMPLETE L3 INFO)---------------------------------->

stop T3113CC

<----------------------------------

� A paging message is broadcast by the MSC to all BSCs controlling cells belonging to the same Location Area as the one of the paged MS.

� In case no MS is accessing the SDCCH channel (T3101 expiry) then the BSC does not repeat the Immediate Assignment since the MS may have accessed an SDCCH in another BSS. It is up to the MSC to repeat Paging if T3113 expires (usually around 7 seconds).

� MC8A counts the number of Paging Command messages sent on a cell.

� MC01 counts the number of MSs which have successfully accessed an SDCCH in a cell as part of a Mobile Terminating (MT) call.

� Caution:

� A paging Request message sent on the Air interface by the BTS may contain several MS identities. 3 Paging Request types can be used:

� in Paging Request Type 1: up to 2 MSs (IMSI1,IMSI2) can be included.

� in Paging Request Type 2: up to 3 MSs (IMSI1,TMSI1,TMSI2) can be included.

� in Paging Request Type 3: up to 4 MSs (TMSI1,TMSI2,TMSI3,TMSI4) can be included.

� On the other hand, a Paging message and a Paging Command message relate to only one MS identity.


1.51

2.3 Typical call failures Radio Link Establishment - Paging

RLE > PagingMC8A=C8A

� Normally all cells of the same Location Area must have the same MC8A counter value since all these cells must be paged for an MT call on an MS located in the Location Area they are included in.

� If not: it means that a cell is not declared in the right LA at NSS level.


1.52

2.3 Typical call failures Radio Link Establishment - RACH counter

RLE > RACHMC8C=C8C

� Caution: All Channels Required (therefore RACH) are counted in MC8C: valid and invalid causes (see later). Indeed ghost RACHsare also counted.

� The Channel Required content corresponds to the Channel Request message sent by the MS to the BTS.

� This Channel Request message is made up of one byte with 2 Informations Elements (IEs):8 7 6 5 4 3 2 1

+-----------------------------------------------+

│ ESTABLISHMENT │ RANDOM ││ + - - - - - - - - + ││ CAUSE │ REFERENCE │+-----------------------------------------------+

� ESTABLISHMENT CAUSEThis information field indicates the reason for requesting the establishment of a connection. This field has a variable length (from 3 bits up to 6 bits).

� RANDOM REFERENCEThis is an unformatted field with a variable length (from 5 bits down to 2 bits).

� Due to the fact that the NECI bit is always set to 1 in Alcatel BSS, Establishment causes can be divided into 2 categories:

� Valid causes: 5 (6 if GPRS)000: Location Update (Normal, Periodic, IMSI Attach)100: Terminating call101: Emergency call 110: Call Re-establishment111: Originating call (not emergency)011: if GPRS is implemented in the cell

� Invalid causes: 3 (2 if GPRS)001: 010: 011: if GPRS is not implemented in the cell


1.53

2.3 Typical call failures Radio Link Establishment - OC success counters split

RLE > success MO splitMC02x=C02x

MC02 = MC02A+MC02B+MC02C+…….+MC02G+MC02H+MC02i

MC02A: LU

MC02B: SMS

MC02C: SS

MC02D: LU follow-on

MC02E: CR

MC02F: unknown

MC02G: IMSI Detach

MC02H: EC or NC

MC02i: LCS

B8

NewB8

� MC02A = Number of SDCCHs successfully seized for Normal or Periodic LU request (IMSI Attach also counted).

� MC02B = Number of SDCCHs successfully seized for Short Message Service.

� MC02C = Number of SDCCHs successfully seized for Supplementary Service.

� MC02D = Number of SDCCHs successfully seized for LU with follow-on bit set to 1 (means that the SDCCH phase will be followed by a TCH assignment for speech call establishment).

� MC02E = Number of SDCCHs successfully seized for Call Re-establishment.

� MC02F = Number of SDCCHs successfully seized in case of L3 Info (within 08.58 ESTABLISH INDICATION) unknown by the BSCbut transferred to the MSC.

� MC02G = Number of SDCCHs successfully seized for IMSI Detach.

� MC02H = Number of SDCCHs successfully seized for Normal or Emergency call.

� MC02i = Number of Mobile Originating SDCCH establishments for LCS purpose.

Also, Evaluation of The Mobiles location (see the next slides)

� LCS: Location Services

B8


1.54

2.3 Typical call failures LCS

LCS function (linked to MC02i) and other counters …

� LCS allows to access the MS location provided by the BSS.

� On MS request to know its own location (MC02 impacted, see the previous slide)

� On network request (especially during Emergency calls)

� On external request (LCS Client)

� Positioning methods provided can be:

� Cell-ID or Cell-ID + TA (Timing Advance)

� Conventional (standalone) GPS

� Assisted GPS (with the help of A-GPS server to compute location)

�MS based (MB): MS is able to perform a pre computation

�MS assisted (MA): MS sends info, Network computes

B8

� Assisted GPS Method:

� Mobile-based: The MS performs OTD signal measurements and computes its own location estimate. In this case the network provides the MS with the additional information such as BTS coordinates and the RTD values. These assistance data can be either broadcast on the CBCH (using SMSCB function) or provided by the BSS in a point to point connection (either spontaneously or on request from the MS).

� Mobile-assisted: The MS performs and reports OTD signal measurements to the network and the network computes the MS location estimate.

� With

� OTD: Observed Time Difference: the time interval that is observed by an MS between the receptions of signals (bursts) from two different BTSs.

� RTD: Real Time Difference: This means the relative synchronization difference in the network between two BTSs.

� Finally, 4 methods are possible for positioning:

� Cell ID+ TA

� Conventional (MS equipped with GPS System)

� A-GPS MS Based

� A-GPS MS Assisted

� These 4 Methods induce a set of counters (2 per method) to give the average latitude and longitude of mobiles in the cell.

� These counters are located in the MFS and can be used in RNO (cartographic part).


1.55


LCS function: Architecture

B8

SMLCBTS

BTS

MS

BSC

MSC

HLR

GMLC

OSP

Lg

Lh

ExternalLCS client

LeA

Abis

Abis

Lb

SMLC function integrated in MFS:

- receives the loc. Request from the GMLC through the MSC/BSC

- Schedules all the necessary actions to get MS location

- Computes MS location

- Provides the result back to the GMLC

MFS

A-GPS

server

SAGI

GPS reference network

LCS: Location ServicesSMLC: Serving Mobile Location Center GMLC: Gateway Mobile Location CenterA-GPS: Assisted GPS

Where is my son?

Where am I?

Where is the accident? Emergency call

MS Request

Network Request

External Request

2

1

3

3

2

1

� In case of MS requests for its location, MC02 is impacted:

� MC02i = Number of Mobile Originating SDCCH establishments for LCS purpose.

� In all cases, some counters related to LCS provide specific information (attempts, success, failures)

� see the next slide.


1.56


Example: Mobile terminated location request failure / success (External request)

B8

SMLCMS BSCBTS LCS ClientMSC

BSSAP-LE Perform_Location_Request

.

GMLC

BSSMAP Perform_Location_Request

BSSAP-LE Perform_Location_Response

BSSMAP Perform_Location_Response

BSSMAP Clear Command and Release

Adequat positionning method chosen by SMLC

HLR

Paging

Authentication + Ciphering

LCS Service Response

LCS Service Request

Send_Routing_Info rqst

Send_Routing_Info resp

Provide_Subscriber_Location

Provide_Subscriber_Location Result

MC923a

MC923b

MC923d

MC923cBSSAP-LE Perform_Location_Response (failure)

BSSMAP Perform_Location_Response (failure)

BSSMAP Perform_Location_Abort

Failure

Success

� Four New counters

� MC923a NB_LCS_REQ Number of location requests received from the MSC in CS domain.

� MC923b NB_LCS_SUCC Number of successful location requests performed in a BSS.

� MC923c NB_LCS_FAIL_LB Number of location requests rejected by the SMLC.

� MC923d NB_LCS_ABORT Number of location aborts received from the MSC in CS domain.

� Calculated indicators based on BSC counters:

� Number of failures on LCS requests due to BSS problem,

� Rate of LCS requests aborted,

� Rate of successes on LCS requests,

� Rate of failures on LCS requests,

� Rate of SDCCH seizures for Location Services.

� Other counters in SMLC (MFS) provide details by type of positioning (CI+TA, Conventional GPS, MS-Assisted A-GPS,MS-Based A-GPS) and for different Error causes.

� See the next slide.


� LCS Counters in MFS:

� QOS FOLLOW UP:

P800: NB_LOC_REQ Number of received LCS requests for MS positioning received from the BSC

P801: NB_ASSIST_DATA_REQ Number of received LCS requests for GPS assistance data (initially requested by the

MS) received from the BSC.

P802: NB_ASSIST_DATA_SUCC Number of successful GPS assistance data delivery (initially requested by the MS)

responses sent to the BSC.

P803: NB_LOC_TA_SUCC Number of successful location responses sent to the BSC using TA positioning method.

P804: NB_LOC_CONV_GPS_SUCC Number of successful location responses sent to the BSC using Conventional GPS

positioning method.

P805: NB_LOC_MA_AGPS_SUCC Number of successful location responses sent to the BSC using MS-Assisted A-GPS

positioning method.

P806: NB_LOC_MB_AGPS_SUCC Number of successful location response sent to the BSC using MS-Based A-GPS

positioning method.

P807: NB_LOC_TA_PCF_REQ Number of location calculation attempts with TA positioning PCF.

P808: NB_LOC_TA_PCF_SUCC Number of location calculations successfully performed with TA positioning PCF.

P809: NB_LOC_CONV_GPS_PCF_REQ Number of location calculation attempts with Conventional GPS PCF.

P810: NB_LOC_MA_AGPS_PCF_REQ Number of location calculation attempts with MS-Assisted A-GPS PCF.

P811: NB_LOC_MA_AGPS_PCF_SUCC Number of location calculations successfully performed with MS Assisted A-GPS PCF.

P812: NB_LOC_MB_AGPS_PCF_REQ Number of location calculation attempts with MS-Based A-GPS PCF.

P813: NB_LOC_MB_AGPS_PCF_SUCC Number of location calculations successfully performed with MS-Based A-GPS.

P814: NB_LCS_PROTOCOL_ERROR Number of failed LCS procedures due to LCS protocol error.

P815: NB_LCS_INTERRUPTED_INTRA_BSC_HO Number of failed LCS procedures due to intra-BSC handover.

P816: NB_LCS_INTERRUPTED_INTER_BSC_HO Number of failed LCS procedures due to inter-BSC handover.

P817: NB_LCS_FAILURE_RRLP Number of failed LCS procedures due to RRLP problem.

P818: NB_LCS_FAILURE_TIMER_EXPIRY Number of failed LCS procedures due to LCS guard timer expiry.

P819: NB_LCS_FAILURE_INTERNAL Number of failed LCS procedures due internal problem detected by the MFS/SMLC.

P820: NB_UNKNOWN_LCS_REQ Number of LCS requests rejected because not supported by the SMLC.

P821: NB_LOC_CONV_GPS_PCF_SUCC Number of location calculations successfully performed with Conventional GPS PCF.

PCF: Positioning Calculation Function

� POSITION AVERAGE USED ON RNO: Values are given in minutes

� LATITUDES AND LONGITUDES:

P822: AV_TA_LAT Average of latitudes for TA Method

P823: AV_TA_LONG Average of longitudes for TA Method

P824: AV_CONV_GPS_LAT Average of latitudes for Conventional GPS Method

P825: AV_CONV_GPS_LONG Average of latitudes for Conventional GPS Method

P826: AV_MA_AGPS_LAT Average of latitudes for MS-Assisted A-GPS Method

P827: AV_MA_AGPS_LONG Average of longitudes for MS-Assisted A-GPS Method

P828: AV_MB_AGPS_LAT Average of latitudes for MS-Assisted A-GPS Method

P829: AV_MB_AGPS_LONG Average of longitudes for MS-Based A-GPS Method

� STANDARD DEVIATION: standard deviation is a measure of the dispersion around the average point

P830: ST_DEV_TA_LAT Standard deviation of the latitude of MS obtained with TA Method

P831: ST_DEV_TA_LONG Standard deviation of the longitude of MS obtained with TA Method

P832: ST_DEV_CONV_GPS_LAT Standard deviation of the latitude of MS obtained with Conventional GPS Method

P833: ST_DEV_CONV_GPS_LONG Standard deviation of the longitude of MS obtained with Conventional GPS Method

P834: ST_DEV_MA_AGPS_LAT Standard deviation of the latitude of MS obtained with MS Assisted A-GPS Method

P835: ST_DEV_MA_AGPS_LONG Standard deviation of the longitude of MS obtained with MS Assisted A-GPS Method

P836: ST_DEV_MB_AGPS_LAT Standard deviation of the latitude of MS obtained with MS Assisted A-GPS Method

P837: ST_DEV_MB_AGPS_LONG Standard deviation of the longitude of MS obtained with MS Assisted A-GPS Method


1.58

2.3 Typical call failures Radio Link Establishment - SDCCH congestion failure

SDCCH ACCESS FAILURE

SDCCH congestionSDCCH congestion

SDCCH RF access failureSDCCH RF access failure

SDCCH access failure BSS pbSDCCH access failure BSS pb

Main failure cases for Radio Link Establishment


1.59

2.3 Typical call failures Radio Link Establishment - SDCCH congestion

RLE > SDCCH congestion

The Immediate Assignment Reject mechanism can be disabled at OMC-R level

� And is not activated for answer to paging

� If disabled, no answer to the MS

� The MS will repeat automatically its request in case of congestion (next slides)

� Waiting for T3122 expiry in case of Immediate Assignment Reject

� Waiting for T3120 expiry otherwise

MS BTS BSCMSC


----------------------------------------------> MC8CNo free SDCCH !!MC04

IMMEDIATE ASSIGN COMMAND<----------------------------------------------

IMM. ASS. REJECT (immediate assignment reject) MC8D, and MC8B<-------------(AGCH)------------

� In case of Immediate Assignment Reject: T3122 = value of Wait_Indication parameter sent by the BSC to the MS.

� Otherwise T3120 is computed by the MS as a random number of slots between:

� 250 and 250+T-1 for a phase 1 MS where: T=Tx_integer parameter (1 value per cell chosen between 3 to 50 slots)

� S and T+S for a phase 2 MS where: T=Tx_integer parameter (1 value per cell chosen between 3 to 50 slots)S is a parameter depending on the CCCH configuration and on the value of Tx_integer as defined in the following table:

TX_integer S(CCCH Not Comb) S(CCCH Combined)

3, 8, 14, 50 55 41

4, 9, 16 76 52

5, 10, 20 109 58

6, 11, 25 163 86

7, 12, 32 217 115


1.60

2.3 Typical call failures Radio Link Establishment - SDCCH congestion counter

RLE > SDCCH congestionMC04=C04


1.61

2.3 Typical call failures Radio Link Establishment - SDCCH cong. consequence


MAIN CONSEQUENCES

� The MS will try "max_retrans +1 " time before giving up

� Immediately for phase 1 MS

� After T3126 for phase 2 MS (still waiting for Immediate Assignment

during this timer)

� In case of "max_retrans+1" failures, the MS will

� Either try an automatic cell reselection

� Or do nothing

� In case of LU, the MS will attempt a new LU request

� In case of Call establishment, the MS will not re-attempt automatically, it is up to the subscriber to try to set up the call again


1.62

2.3 Typical call failures Radio Link Establishment - SDCCH cong. causes


MAIN CAUSES

� Too much SDCCH "normal" traffic for cell SDCCH design

� Radio resource capacity not sufficient (too many calls)

� Inadequate LA design (too many LUs)

� "Common Transport Effect"

� Difficult to avoid for small cells

� Abnormal SDCCH traffic

� ”Phantom" channel requests (seen in SDCCH RF failure session)

� Neighboring cell barred

� SDCCH congestion can be too high because of the subscribers' traffic demand in terms of calls / LU.

� Solution = add a TRX or site / redesign the LA plan

� High SDCCH congestion can be observed at peculiar period of the day due to a peak of LU requests generated by a big group of subscribers entering a new LA at the same time (bus, train, plane).

� Solution = redesign the LA plan or play on radio parameters (CELL_RESELECT_HYSTERESIS, WI_OP)

� High SDCCH congestion can be abnormally observed without real MS traffic in case a high level of noise or the proximity of a non-GSM radio transmitter.

� Solution = change the BCCH frequency or put an RX filter

� High SDCCH congestion can also be abnormally observed in a cell in case one of its neighboring cell is barred.

� Solution = Remove the barring


1.63

2.3 Typical call failures Radio Link Establishment - SDCCH cong. Resolution?


DYNAMIC SDCCH ALLOCATION

� Defining too many SDCCHs will lead to a lack of TCH resources... and money.

� Defining too few SDCCH channels will result in SDCCH congestion. TCH channels cannot be allocated and, once again, the operator 's revenue decreases.

� At OMC-R level, it is possible to configure:

� a set of static SDCCH/x timeslots to handle normal SDCCH traffic;

� a set of dynamic SDCCH/8 timeslots, which can be used for TCH traffic, or for SDCCH traffic depending on the need.

� With the "Dynamic SDCCH allocation" feature, the BSS is automatically looking after varying SDCCH traffic and is particularly adapted to the situations such as: change of LA, change of SMS traffic model, SDCCH traffic varying due to LCS.

� This feature is particularly useful in very dense (hierarchical) networks, where the effort to optimize the SDCCH configuration becomes more important.

B8

� This feature not only improves SDCCH congestion but also successful TCH assignment rates.


1.64

2.3 Typical call failures Radio Link Establishment - SDCCH cong. Resolution?


DYNAMIC SDCCH ALLOCATION

B8

CHANNEL REQUEST

CHANNEL REQUIRED

MS BTS BSC

(RACH)

If No free SDCCH, then

run dynamic SDCCH/8 timeslot allocation

algorithm. If allocation is successful, then

activate dynamic SDCCH sub-

channel and serve request

If allocation was unsuccessful, then reject SDCCH request (possibly

using the Immediate Assignment Reject procedure).

MC801a&b

MC802a&b

� SPECIFIC COUNTERS (Type 110 / Cell Level):

� MC800 Average number of available dynamic SDCCH/8 timeslots.

� MC801a Average number of busy dynamic SDCCH/8 timeslots allocated as TCH (FR or HR).

� MC801b Maximum number of busy dynamic SDCCH/8 timeslots allocated as TCH (FR or HR).

� MC802a Average number of busy SDCCH sub-channels allocated on the dynamic SDCCH/8 timeslots.

� MC802b Maximum number of busy SDCCH sub-channels allocated on the dynamic SDCCH/8 timeslots.

� These four previous counters are”Inspection Counters” ; that means than the resource is checked regulary by the BSC and at the end of the period, an average is done. Example: 3 physical chanels are defined as Dyn SDCCH and the counter give the following indication:MC801a = 1.7 that means sometimes the 3 Dyn SD are allocated as TCH, sometimes only 2 of them, sometimes 1 or 0 and the average is 1.7

� The FOLLOWING COUNTERS ARE IMPACTED BY the Dynamic SDCCH Allocation feature:

� MC28, MC29 The Number of busy radio timeslots in TCH usage takes into account the busy TCH timeslots and the dynamic SDCCH/8 timeslots allocated as TCH.

� C30, MC31 The Number of busy SDCCH sub-channels takes into account the SDCCH sub-channels allocated on the static and dynamic SDCCH/8 timeslots.

� C370a, MC370a, C370b, MC370b The Number of times the radio timeslots are allocated for TCH usage (FR / HR) takes into account the busy TCH timeslots and the dynamic SDCCH/8 timeslots allocated as TCH.

� C/MC380a/b C/MC381a/b The Cumulated time (in second) the radio timeslots are allocated for TCH usage (FR or HR)does not take care whether the TCHs are allocated on the TCH radio timeslot or on the dynamic SDCCH/8 timeslots.

� C39, MC390, C40, MC400 The Number of times or the Cumulated time (in second) the SDCCH sub-channels are busydoes not take care whether the SDCCH sub-channels are allocated on the static or dynamic SDCCH/x timeslot.

� C/MC34 C/MC380 The Cumulated time (in second) all TCHs / SDCCHs in the cell are busydoes not take care whether the TCHs / SDCCHs are allocated on the TCH radio timeslot /SDCCH/x timeslot or on the dynamic SDCCH/8 timeslots.

� C/MC320a/b/c/d/e Free TCH radio timeslotscount the free TCH timeslots and the free dynamic SDCCH/8 timeslots.


1.65

2.3 Typical call failures Radio Link Establishment - SDCCH radio failure

TYPICAL CALL FAILURES







1.66

2.3 Typical call failures Radio Link Establishment - SDCCH radio access failure

RLE > SDCCH RF Failure

MS BTS BSC MSC





IMMEDIATE ASSIGN <---------------------------------------------- start T3101<------------(AGCH)------------- MC8B

IMMEDIATE ASSIGN-------(SDCCH)-----X

T3101expiry->“radio failure”MC149

� MC149 counts the number of SDCCH access failures due to radio problems.


1.67

2.3 Typical call failures Radio Link Establishment - real radio problems


Main causes > real radio problems

� Unbalanced cell power budget

� Bad coverage (for example a moving car)

� Interference (for example downlink)

� In case of radio failure, the MS will retry as for SDCCH congestion

� Unbalanced Power Budget:

� Bad coverage:

� Interference:

DL interference area

AGCH lost

RACH

building

BTS

Channel Request

Access Grant

Max Path Loss UL

Max Path Loss DL

AGCH

RACH


1.68

2.3 Typical call failures Radio Link Establishment - Ghost RACH (1/7)


Main causes > "Phantom/Ghost/Spurious/Dummy ... RACH"

� Channel request received but not sent: 3 causes

� Noise decoding

� Reception of channel request sent to a neighboring cell

� Reception of HO_ACCESS sent to a neighboring cell


1.69

2.3 Typical call failures Radio Link Establishment - Ghost RACH (2/7)


Main causes > "Phantom/Ghost/Spurious/Dummy ... RACH"

� Example of a channel required message

� For this Channel Required, the establishment cause is valid (Call re-establishment) but the Access Delay (corresponding to the distance between the MS and the BTS) is high.

� Indeed the Access Delay being equal to the Timing Advance is coded in slot unit representing a distance of 550m. It can take values from 0 (0m) to 63 (35km).

� Thus the Channel Required above is received from an MS located at 19km from the site. It may therefore be rather a ghost RACH than a real MS which wants re-establish a call.

� In Alcatel BSS, there is possibility to filter the Channel Required received from a distance greater than a distance defined as a parameter value: RACH_TA_FILTER tunable on a per cell basis. Caution should be taken since a too low value may reduce the network coverage.


1.70

2.3 Typical call failures Radio Link Establishment - Ghost RACH causes (3/7)


Main causes > "Phantom RACH" >noise decoding

� GSM 05.05: " 0.02 % of Rach Frame can be decoded without error without real input signal"

� BCCH not combined: 51 Rach/Multi Frame > (3600 * 1000) ms / 4.615 ms at 0.02 %: 156

dummy RACH/hour

� BCCH combined: 27/51 RACH/Multi-Frame > 83 dummy RACH/hour

� 3/8 of causes (field of channel request, 5 valid causes over 8) will be unvalid

� Example of induced SDCCH traffic: (5/8*156*T3101 (3 sec))/3600 = 0.08 Erlang SDCCH

� This extra-load has no impact for the system

� Some tips:

� Dummy Rach load depends on minimum level for decoding configured in Evolium BTS

� During period with low real traffic (night), high rate of dummy RACH

� For dummy RACH, the channel required has a random value of TA

STRUCTURE of the MULTIFRAME in "TIME SLOT" 0STRUCTURE of the MULTIFRAME in "TIME SLOT" 0STRUCTURE of the MULTIFRAME in "TIME SLOT" 0STRUCTURE of the MULTIFRAME in "TIME SLOT" 0

-

R = RACH

DOWNLINKDOWNLINKDOWNLINKDOWNLINKf s b b b b C C C C

31 51 1211 2 3 4 5 6 7 8 9 10 20 41f s f s f s f sC C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C -

(Multiframes of 51 frames)

f = FCCH s = SCH b = BCCH

f s

C C C C = CCCH (PCH or AGCH)

UPLINKUPLINKUPLINKUPLINKR R R RR R R R R R R RR R R R R R R RR R R R R R R RR R R R R R R RR R R RR R R RR R R R R R

(Non(Non(Non(Non----combined BCCH)combined BCCH)combined BCCH)combined BCCH)

(Combined BCCH)(Combined BCCH)(Combined BCCH)(Combined BCCH)

R = RACH R = RACH R = RACH R = RACH

DOWNLINKDOWNLINKDOWNLINKDOWNLINK

F = FCCH S = SCH B = BCCH C = CCCH (PCH or AGCH)C = CCCH (PCH or AGCH)C = CCCH (PCH or AGCH)C = CCCH (PCH or AGCH)

UPLINKUPLINKUPLINKUPLINK

F S B CCCC F S F S F S -F SCCCC CCCC D0D0D0D0 D1D1D1D1 D2D2D2D2 D3D3D3D3 A0A0A0A0 A1A1A1A1

F S B CCCC F S F S F S -F SCCCC CCCC D0D0D0D0 D1D1D1D1 D2D2D2D2 D3D3D3D3 A2A2A2A2 A3A3A3A3

RRRR RRRR RRRR RRRRRRRR RRRR RRRR RRRR RRRR RRRR RRRR RRRRRRRR RRRR RRRR RRRR RRRR RRRR RRRRRRRR RRRR RRRR RRRR RRRR RRRRRRRR RRRRD3D3D3D3 A2A2A2A2 A3A3A3A3 D0D0D0D0 D1D1D1D1 D2D2D2D2

RRRR RRRR RRRR RRRRRRRR RRRR RRRR RRRR RRRR RRRR RRRR RRRRRRRR RRRR RRRR RRRR RRRR RRRR RRRRRRRR RRRR RRRR RRRR RRRR RRRRRRRR RRRRD3D3D3D3 A0A0A0A0 A1A1A1A1 D0D0D0D0 D1D1D1D1 D2D2D2D2

DnDnDnDn/An = SDCCH/SACCH/4 /An = SDCCH/SACCH/4 /An = SDCCH/SACCH/4 /An = SDCCH/SACCH/4

51 multiframe duration = 51 x 8 x 0,577 = 235ms


1.71



Main causes > "Phantom RACH" >noise decoding

� No subscriber -> no impact for subscriber

� But MC149 incremented -> SDCCH RF access failure is impacted

MS BTS BSC MSC

CHANNEL REQUIRED

----------------------------------------------> MC8C

CHANNEL ACTIVATION (SDCCH)

<---------------------------------------------- MC148

CHANNEL ACTIVATION ACK

---------------------------------------------->

IMMEDIATE ASSIGN COMMAND

IMMEDIATE ASSIGN <---------------------------------------------- start T3101

<------------ (AGCH) ------------- MC8B

T3101expiry

->“radio failure

MC149


1.72



Main causes > "Phantom RACH" > Channel Request

sent to the neighboring cell

� Subscriber not impacted (real transaction performed elsewhere)

� But MC149 incremented -> SDCCH RF access failure is impacted

� Usual radio planning rules are sufficient to avoid the trouble

� 2 cells must not have same (BCCH, BSIC) couple

M S B T S B S C M S C

C H A N N E L R E Q U IR E D---- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -> M C 8 C

C H A N N E L A C T IV A T IO N (S D C C H )

< --- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - M C 1 4 8

C H A N N E L A C T IV A T IO N A C K---- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ->

IM M E D IA T E A S S IG N C O M M A N DIM M E D IA T E A S S IG N < --- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - s ta r t T 3 1 0 1 M C 8 B

< ---- - - - - - - - - (A G C H )- - - - - - - - - - - - -

T 3 1 0 1 e x p iry M C 1 4 9

-> “ra d io fa ilu re

� BSIC = BCC (3 bit) + NCC (3 bit)

� BCC: BTS Color Code

� NCC: Network Color Code


1.73




due to handover

� During HO, the first message sent to the target cell is HO Access

� This message is an Access Burst like Channel Request

� If received on BCCH, can be understood as a Channel Request (RACH)

� A new case of "Phantom RACH"


1.74




due to handover

This case is the most dangerous

� The MS sends usually a sequence of HO Access message, every frame

� In some cases, this can create a phantom RACH if

� The frequency of the TCH is identical or adjacent to the one of interfered BCCH

� Characteristics of such phantom RACH (Channel Required)

� Subsequent frame number

� Random, but stable timing advance

� Can block very easily SDCCH


1.75

2.3 Typical call failures Radio Link Establishment - BSS failure

TYPICAL CALL FAILURES







1.76

2.3 Typical call failures Radio Link Establishment - BSS problem

RLE > BSS problem

� No specific counter

MS BTS BSC MSC





IMMEDIATE ASSIGN <---------------------------------------------- start T3101<------------(AGCH)------------- MC8B

SABM (L3 info)------------(SDCCH)------------>

� BSS Problems are difficult to specify a priori. It is better to deduce them from other counters which are easier to implement thus more reliable.


1.77

RLE counters

2.3 Typical call failures Radio Link Establishment - counters

Request MC8C

GPRS causes P62C

GSM invalid causes unknown

Preparation GSM valid causes unknown

Congestion MC04

BSS Pb unknown

Execution Attempt MC148

Radio Access Failure MC149

BSS Pb MC148 - (MC01+MC02) - MC149

Success MC01+MC02

Radio Link Establishment

REQUEST

Congestion

ATTEMPT

Radio access failure

SUCCESS

BSS problem

Preparation Failure

Execution Failure

GPRS causes GSM/GPRS invalid causes GSM valid causes

BSS problem

� Statistically a ghost RACH can correspond to any kind of establishment cause: valid and invalid.

� As ghost RACH which corresponds to a GSM valid cause will lead to an SDCCH allocation which will not be seized by an MS, it will lead to the incrementation of MC149 counter and therefore counted as an SDCCH access failure due to radio.


1.78

2.3 Typical call failures Radio Link Establishment - indicators

TYPICAL CALL FAILURES: RLE indicators

� Refer to BSS - DEFINITION OF QUALITY OF SERVICE INDICATORS:

� GLOBAL Quality of service INDICATORS > SDCCH > Assignment Phase

� SDNAUR: SDCCH assignment unsuccess rate

� SDNACGR: SDCCH assignment failure rate due to congestion (Global)

� SDNAFLRR: SDCCH assignment failure rate due to radio

� SDNAFLBR: SDCCH assignment failure rate due to BSS problem

� A SDCCH radio access failure due to ghost RACH occurrence is easily observed during low traffic hour (night time) since ghost RACHs are almost the only cause of failure.


1.79

2.3 Typical call failures SDCCH phase - OC success

Successful SDCCH phase: OC call

� transparent message: no dedicated counters

MS BTS BSC MSC

SDCCH Phase : Originating Call case

< -------------------------------------------------------------------------------------------------------------------------AUTHENTICATION REQUEST

------------------------------------------------------------------------------------------------------------------------- >AUTHENTICATION RESPONSE

< -------------------------------------------------------------------------------------------------------------------------CIPHERING MODE COMMAND

------------------------------------------------------------------------------------------------------------------------- >CIPHERING MODE COMPLETE

------------------------------------------------------------------------------------------------------------------------- >SETUP

< -------------------------------------------------------------------------------------------------------------------------CALL PROCEEDING

� Transparent messages (DTAP) are used in order the NSS performs control procedures to enable the MS to set up a speech call.

� Authentication: Checks that the Mobile Station is the required station and not an intruder.

� Ciphering: All Information (signaling, Speech and Data) is sent in cipher mode, to avoid monitoring and intruders (who could analyze signaling data).

� Setup/Call Processing: call is being processed between the calling Party and the Called Party.


1.80

2.3 Typical call failures SDCCH phase - TC success

Successful SDCCH phase: TC call


MS BTS BSC MSC

SDCCH Phase : Terminating Call case





< -------------------------------------------------------------------------------------------------------------------------SETUP

------------------------------------------------------------------------------------------------------------------------- >CALL CONFIRM

� Setup/Call Confirm: the call is being processed between the Calling Party and the Called Party.


1.81

2.3 Typical call failures SDCCH phase - LU success

successful SDCCH phase: Location Update


MS BTS BSC MSC

SDCCH Phase : Location Update Case (with TMSI reallocation)

------------------------------------------------------------------------------------------------------------------------- >LOCATION UPDATE REQUEST





< -------------------------------------------------------------------------------------------------------------------------LOCATION UPDATE ACCEPT

------------------------------------------------------------------------------------------------------------------------- > TMSI REALLOCATION COMPLETE

� Some transparent messages are also exchanged between the MS and the network in case of a Location Update transaction.


1.82

2.3 Typical call failures SDCCH phase - drops

SDCCH phase

� Loss of connection during SDCCH phase = "SDCCH drop"

� 3 origins of SDCCH drop

� Radio problems when connected on SDCCH

� BSS problems

� Call lost during an SDCCH HO (handover failure without reversion to old channel)

� Generally SDCCH handover are disabled in the network since the average SDCCH duration is only around 2 to 3 seconds.


1.83

2.3 Typical call failures SDCCH phase - radio drop

SDCCH phase > drop radio

� Connection lost due to radio problem

MS BTS BSC MSC

SDCCH Phase established

Radio connection lost---------------------------------------------------- > MC138CONNECTION FAILURE INDICATION

(cause : radio link failure)--------------------------------------- >CLEAR REQUEST

Cause : radio interface failure

� MC138 counts the number of SDCCH channel drops due to radio problems.

� Radio problems can be due to coverage, interference and sometimes BSS dysfunction which is not detected as a system alarm the by O&M Fault Management application.


1.84

2.3 Typical call failures SDCCH phase - BSS drop

SDCCH phase > drop BSS

� Connection lost due BSS problem

MS BTS BSC MSC


MC137

--------------------------------------- >CLEAR REQUEST

Cause : O&M interventionCause : radio interface failure

� MC137 counts the number of SDCCH channel drops due to BSS problems.

� A BSS problem can be a BTS/BSC hardware or software failure. It can also be due to a problem on the Abis interface (due to Micro Wave transmission for instance).


1.85

SDCCH phase > drop HO

� Connection lost during HandOver

MS BTS BSC MSC


HO FAILURE WITHOUT REVERSION MC07--------------------------------------- >

CLEAR REQUEST

Radio Interface Message Failure (Alcatel)

2.3 Typical call failures SDCCH phase - HO drop

� MC07 counts the number of SDCCH channel drops due to handover failure.


1.86

SDCCH phase counters

2.3 Typical call failures SDCCH phase - counters

SDCCH connection MC01+MC02+MC10

SDCCH Drop Drop radio MC138

Drop BSS MC137

Drop HO MC07

SDCCH Phase

TCH assignment phase SDCCH drop

SDCCH connection

Normal release

Drop radio

Drop BSS

Drop HO


1.87

2.3 Typical call failures SDCCH phase - indicators

SDCCH phase indicators

� Refer to BSS - DEFINITION OF QUALITY OF SERVICE INDICATORS RELEASE B8:

� GLOBAL Quality of service INDICATORS > SDCCH > Established phase

� SDCDR: SDCCH drop rate (Global)

� SDCDRR: SDCCH drop rate due to radio problem

� SDCDBR: SDCCH drop rate due to BSS Problem

� SDCDHR: SDCCH drop rate due to HO failure


1.88

2.3 Typical call failures SDCCH phase - exercise

SDCCH phase: Exercises

� With K1205 (file PAIB29.REC)

� Extract a location update (successful case)

� Extract a transaction with an SDCCH drop

What is the cause of the failure?

Is it possible to "guess" the type of transaction (OC, TC, LU,etc)?

� As 2, but for a different cause

Time allowed:

15 minutes


1.89

2.3 Typical call failures TCH assignment - success

TCH assignment success case

� T3107: guard timer for TCH assignment

MS BTS BSC MSC

TCH ASSIGNMENT PHASE (OC or TC)

< -----------------------------------ASSIGNMENT REQUEST

< --------------------------------------------------------PHYSICAL CONTEXT REQUEST

-------------------------------------------------------- >PHYSICAL CONTEXT CONFIRM

< -------------------------------------------------------- MC703CHANNEL ACTIVATION (TCH)

-------------------------------------------------------- >CHANNEL ACTIVATION ACKNOWLEDGE

< ----------------------------------------------------------------------------------- Start T3107 (SDCCH) ASSIGNMENT COMMAND

---------------------- >TCH SABM -------------------------------------------------------- >

< ---------------------- ESTABLISH INDICATIONUA

----------------------------------------------------------------------------------- > Stop T3107ASSIGNMENT COMPLETE MC718

----------------------------------- >ASSIGNMENT COMPLETE

MC140a

MC140b

B8

MC460a New B8

MC140a

MC140b

MC460a

(see comments)

� MC703 counts the number of TCH channels activated (therefore allocated) in a cell.

� MC718 counts the number of MSs which have successfully accessed a TCH in a cell as part of a call establishment (Normal Assignment).

� Both counters are new from B7 since they are now implemented at TRX level.

� MC140a counts the number of normal assignment requests for TCH establishment.

� MC140b counts the number of normal assignment commands for TCH establishment.

� Both counters are new in B8 in order to discriminate BSS problems in Preparation and Execution phases.

� MC460a is a new counter in B8 for type 110: NB_TCH_EMERGENCY_HO_PRESERVATION: Definition: Number of high priority TCH requests served when:

� the number of free TCH timeslots is less than or equal to NUM_TCH_EGNCY_HO.

� the queue for this cell is not empty.

� MC140a, MC140b and MC460 are given at Cell level


1.90

TCH assignment > congestion

� 5 causes of congestion ⇒ 5 counters: C612A, B, C, D, E whenever

� Queuing is not allowed

� Queue is Full

� T11 expires

� RTCH request is removed from the queue due to a higher priority

request to be queued

� No Abis-TCH resource is available (Restriction in B8)

MS BTS BSC MSC


< -----------------------------------------------ASSIGNMENT REQUEST

No RTCH available on requested cell MC812

------------------------------------------------ >ASSIGNMENT FAILURE

Cause No Radio Resource Available

2.3 Typical call failures TCH assignment - TCH congestion

B8 (See comments)

� New counter in B8: C612E: Number of 08.08 ASSIGNMENT REQUEST for TCH normal assignment rejected due to congestion on the Abis interface.

� Therefore B6 counter MC612 is replaced by MC812 from B7. MC812 = C612A+C612B+C612C+C612D+C612E of PM Type 1.

� But as C612E is in restriction in B8 (always = 0) then MC812(B7) = MC612(B6)

� MC612A, MC612B, MC612C, MC612D also exist in PM Type 110.

� A TCH request is attached a Priority Level from 1 (highest priority) to 14 (lowest priority).


1.91

TCH assignment > radio failure

� Radio problem

MS BTS BSC MSC








SABM----(TCH)------X

T3107 ExpiryMC746B----------------------------------- >

ASSIGNMENT FAILURERadio interface failure

2.3 Typical call failures TCH assignment - radio failure

MC140a

MC140b

� MC746B counts the number of TCH access failures due to radio problems.

� MC746B counter is implemented at TRX level from B7.

� In case of TCH access failure, the MS will try to revert back to the SDCCH channel. Whether it succeeds in reverting to the SDCCH or not the call establishment fails. On the other hand some MSCs may resend the ASSIGNMENT REQUEST again.


1.92

TCH assignment > BSS problem

� BSS problem (Abis, BTS/BSC HW or SW)

2.3 Typical call failures TCH assignment - BSS problem

MS BTS BSC MSC








SABM----(TCH)---- >

MC14B

MC140a

MC140b

No specific counter

B8

� The number of TCH Assignment failures due to BSS Pb can be correctly deduced and distinguished for preparation and execution phases from B8 with the 2 new counters MC140a and MC140b.(see the next slide)


1.93

TCH assignment counters

2.3 Typical call failures TCH assignment - counters

Congestion

ATTEMPT

Radio access failure

SUCCESS

BSS problem

Preparation Failure

Execution Failure

REQUEST

BSS problemTCH Assignment

Preparation Request MC140a

Congestion MC812

BSS Pb MC140a-MC140b-MC812

Execution Attempt MC140b

Radio Access Failure MC746b

BSS Pb MC140b-MC718-MC746b

Success MC718

B8

NewB8

BSS PB

discrimination


1.94

TCH Assignment indicators

2.3 Typical call failures TCH assignment - indicators


� GLOBAL Quality of service INDICATORS > RTCH > Assignment Phase

� TCNAUR: TCH assignment unsuccess rate (Global)

� TCNACGR: TCH assignment failure rate due to congestion

� TCNAFLRR: TCH assignment failure rate due to radio problems

� TCNAFLBR: TCH assignment failure rate due to BSS Problems.

� From B7.2 some indicators can be provided on a per TRX basis due to the availability of new counters provided per TRX in Type 110:

� TCNAEFR = RTCH_assign_efficiency_rate (RNO name) = MC718 / MC703

� Rate of successful RTCH seizures in relation to all RTCHs allocated, during the TCH assignment procedure.

� TCNAAFLRR = RTCH_assign_allocated_fail_radio_rate (RNO name) = MC746B / MC703

� Rate of RTCH seizures failed during the normal assignment procedure because of radio problems in relation to all RTCHs allocated for TCH assignment procedure.

� This will help a lot to detect bad QOS due to TRX hardware related problem.


1.95

TCH assignment failure


� Find and extract a case of TCH congestion (if any)

� Find and extract a case of assignment failure due to radio problem (if any)

2.3 Typical call failures TCH assignment - exercise

Time allowed:

15 minutes


1.96

TCH phase

� Transparent messages for BSS, no specific counters

� TCH DROP: any problems occurring after TCH assignment (during or after connection) cannot be discriminated

MS BTS BSC MSC

Alerting Connection Phase (OC case) : ringing phase

< ---------------------------------------------------------------------------------------------------------------------------ALERTING

< ---------------------------------------------------------------------------------------------------------------------------CONNECT

--------------------------------------------------------------------------------------------------------------------------- >CONNECT ACK

MS BTS BSC MSC

Alerting Connection Phase : TC case

--------------------------------------------------------------------------------------------------------------------------- >

ALERTING

--------------------------------------------------------------------------------------------------------------------------- >CONNECT

< ---------------------------------------------------------------------------------------------------------------------------CONNECT ACK

2.3 Typical call failures TCH phase - success

MS BTS BSC MSC





< --------------------------------------------------------CHANNEL ACTIVATION (TCH)


< ----------------------------------------------------------------------------------- Start T3107

(SDCCH) ASSIGNMENT COMMAND

---------------------- >TCH SABM -------------------------------------------------------- >

< ---------------------- ESTABLISH INDICATIONUA

----------------------------------------------------------------------------------- > Stop T3107

ASSIGNMENT COMPLETE----------------------------------- >ASSIGNMENT COMPLETE

< ---------------------------------------------------------------------------------------------------------------------------ALERTING

< ---------------------------------------------------------------------------------------------------------------------------

CONNECT---------------------------------------------------------------------------------------------------------------------------->

CONNECT ACK

Call Setup

Call phase

Call Setup

Call phase

� The Call setup phase and the Stable call phase are not corresponding between the BSS and the NSS.

� For the BSS, a call is established when the MS has successfully accessed a TCH channel on the Air interface.

� For the NSS, a call is established when the speech data exchanged is started between end users.

� Thus the Call setup phase is shorter and the Call phase is longer in the BSS.

� Therefore Call Setup Success rate is worse in the NSS and the Call Drop rate is worse in the BSS.


1.97

TCH phase > drop radio

� Radio problem

MS BTS BSC MSC

Alerting Connection Phase or Communication : at any time

Radio problem-------------------------------------------------------- > MC736

CONNECTION FAILURE INDICATION --------------------------------------- >Cause radio link failure CLEAR REQUEST

Cause radio interface failure(alcatel)

2.3 Typical call failures TCH phase - radio drop

� MC736 counts the number of TCH channel drops due to radio problems.

� MC736 counter is implemented at TRX level from B7.

� Radio problems can be due to coverage, interference and sometimes BSS dysfunction which is not detected as a system alarm by the O&M Fault Management application.


1.98

TCH phase > drop TC

� Remote TransCoder problem

MS BTS BSC MSC


Radio problem-------------------------------------------------------- > MC739

CONNECTION FAILURE INDICATION --------------------------------------- >Remote transcoder failure CLEAR REQUEST

Equipment failure

2.3 Typical call failures TCH phase - remote TC drop

� MC739 counts the number of TCH channel drops due to BSS problems reported as "remote TransCoder failure".


� It can usually be a bad quality of the transmission on the Abis interface (Micro Wave) or a faulty hardware component in the TransCoder or even sometimes BSS software/hardware problems.


1.99

TCH phase > drop BSS internal

� Other internal BSS problem (excluding TC)

MS BTS BSC MSC


MC14C--------------------------------------- >

CLEAR REQUEST

O&M interventionRadio interface failure

2.3 Typical call failures TCH phase - BSS internal drop

� MC14C counts the number of TCH channel drops due to BSS problems other than the ones reported by the TransCoder.

� A BSS problem can be a BTS/BSC hardware or software failure.


1.100

TCH phase > drop HO

� Handover failure

MS BTS BSC MSC


HO FAILURE WITHOUT REVERSION MC621--------------------------------------- >

CLEAR REQUEST

Radio Interface Message Failure (Alcatel)

2.3 Typical call failures TCH phase - HO drop

� MC621 counts the number of TCH channel drops due to Handover failure.


� This event is also counted in the set of Handover counters as an Outgoing handover failure without reversion to the old channel.


1.101

TCH phase > drop preemption

� TCH preempted

MS BTS BSC MSC

Alerting Connection Phase of a callwith priority level pl2 and preemption vulnerability indicator pvi=1

no TCH free

ASSIGNMENT REQUEST

<---------------------------------------Priority level pl1 > pl2

preemption capability indicator pci=1

MC921C--------------------------------------- >

CLEAR REQUEST

preemption

2.3 Typical call failures TCH phase - preemption drop

� MC921C counts the number of TCH channel drops due to preemption for another call to be established.

� MC921C counter exists from B7 as linked to the feature Preemption.


1.102

TYPICAL CALL FAILURES: TCH phase counters

2.3 Typical call failures TCH phase - counters

TCH connection MC718+MC717A+MC717B

Outgoing HO success MC712

Call drop Drop radio MC736

Drop TC MC739

Drop internal BSS MC14C

Drop HO MC621

Drop preemption MC921C

Normal release unknown

NSS abnormal release unknown

TCH Phase

Outgoing HO success Call drop

TCH connection

Normal release

Call drop radio

Call drop BSS

Call drop HO

Call drop preemption

TC

BSS internal

NSS abnormal release


1.103

TYPICAL CALL FAILURES: TCH phase indicators

� Call drop rate = call drop / RTCH success end

� RTCH success end = RTCH assignment success

+ RTCH incoming (HO+DR) success

- RTCH outgoing HO

2.3 Typical call failures TCH phase - call drop rate

Incoming internal HO+DRIncoming internal HO+DRIncoming internal HO+DRIncoming internal HO+DR

BSS1 BSS2

Incoming external HO+DRIncoming external HO+DRIncoming external HO+DRIncoming external HO+DR

outgoing HOoutgoing HOoutgoing HOoutgoing HO

TCH assignmentTCH assignmentTCH assignmentTCH assignment

� QSCDN = call drop

= drop radio + drop TC + drop internal BSS + drop HO + drop Preemption

= MC736 + MC739 + MC14C + MC621 + MC921C

� TCQHCCN = RTCH success end

= assignment success + incoming (HO+DR) success - outgoing HO

= MC718 + (MC717A+MC717B) - MC712

� As MC718, MC717A, MC717B and MC712 are provided per TRX, the “RTCH success end” indicator (TCAHCCN) can be computed per TRX.

� But since only MC736 (drop radio), MC739 (drop TC) and MC621 (drop HO) are provided per TRX, the “call drop rate” indicator (QSCDR) can be computed per CELL only.

� On the other hand the following call drop indicators can be computed per TRX:

� call drop radio rate (QSCDRR) = call drop radio / RTCH success end

� call drop HO rate (QSCDHR) = call drop HO / RTCH success end

� call drop TC rate (QSCDBTR) = call drop TC / RTCH success end

� Note:

� MC718 counts the number of successful TCH assignments.

� MC717A counts the number of successful internal DRs.

� MC717B counts the number of successful incoming internal and external (HOs+DR) as well as the number of intra cell HOs successfully performed.

� MC712 counts the number of successful outgoing internal and external HOs as well as the number of intra cell HOssuccessfully performed.


1.104


� RTCH drop rate = call drop / RTCH success begin

� RTCH success begin = RTCH assignment success

+ RTCH incoming (HO+DR) success

- RTCH intra cell HO success

2.3 Typical call failures TCH phase - RTCH drop rate

BSS1 BSS2



Incoming external HO+DRIncoming external HO+DRIncoming external HO+DRIncoming external HO+DR

outgoing HOoutgoing HOoutgoing HOoutgoing HO

IntraIntraIntraIntra----cell HOcell HOcell HOcell HO



= MC736 + MC739 + MC14C + MC621 + MC921C

� TCQHSUBN = RTCH success begin

= assignment success + incoming (HO+DR) success - intra cell HO

= MC718 + (MC717A+MC717B) - MC662

� As MC662 is not provided per TRX, the “RTCH success begin” indicator (TCAHSUBN) cannot be computed per TRX but per CELL only.

� Therefore all “RTCH drop rate” indicators can be computed per CELL only.

� Note:

� MC662 counts the number of successful TCH intracell HOs.


1.105


� TRX TCH drop rate = call drop / RTCH success

� RTCH success = RTCH assignment success+ RTCH incoming (HO+DR) success

2.3 Typical call failures TCH phase - TRX TCH drop rate



outgoing HOoutgoing HOoutgoing HOoutgoing HOBSS1 BSS2

Incoming external HO+DRIncoming external HO+DRIncoming external HO+DRIncoming external HO+DRIntraIntraIntraIntra----cell HOcell HOcell HOcell HO



= MC736 + MC739 + MC14C + MC621 + MC921C

� TCAHSUN = RTCH success

= assignment success + incoming (HO+DR) success

= MC718 + (MC717A+MC717B)

� Whereas some call drop rate indicators are defined per TRX and per CELL, TRX RTCH drop rate indicators are defined at TRX level only.

� As MC718, MC717A, MC717B are provided per TRX, the “RTCH success” indicator (TCAHSUN) can be computed per TRX.

� But since only MC736 (drop radio), MC739 (drop TC) and MC621 (drop HO) are provided per TRX, a global“TRX RTCH drop rate”indicator cannot be provided.

� On the other hand, the following TRX RTCH drop indicators can be computed:

� TRX_RTCH_drop_radio_rate (TCAHCDRTR) = call drop radio / RTCH success

� TRX_RTCH_drop_HO_rate (TCHOCDTR) = call drop HO / RTCH success

� TRX_RTCH_drop_BSS_remote_TC_rate (TCTRTCDTR) = call drop TC / RTCH success

� CAUTION: Intra-cell HO being counted in MC717B and not deduced in the RTCH success computation in order to provide the TRX RTCH drop indicators at TRX level then these indicators may be abnormally low (good) if a large amount of intra-cell HOs are performed in the cell (concentric cell, multiband cell).



� call drop indicators: all of them are available per CELL only and some of them per TRX

� GLOBAL Quality of service INDICATORS > Call Statistics > Call drop

�QSCDR: call drop rate (Global): CELL

�QSCDRR: call drop rate due to radio: CELL + TRX

�QSCDBIR: call drop rate due to BSS internal problem: CELL

�QSCDBTR: call drop rate due to TransCoder reported problem: CELL + TRX

�QSCDHR: call drop rate due to HO failure: CELL + TRX

�QSCDPR: call drop rate due to preemption: CELL

� RTCH drop indicators: all of them are available per CELL only

� GLOBAL Quality of service INDICATORS > RTCH > Established phase

�QSTCCDR: RTCH drop rate

�TCAHCDRR: RTCH drop rate due to radio problem

�TCTRICDBR: RTCH drop rate due to BSS internal problem

�TCTRTCDR: RTCH drop rate due to TransCoder reported problem

�TCHOCDR: RTCH drop rate due to HO failure

�TCPPCDR: RTCH drop rate due to preemption

� TRX TCH drop indicators: all of them are available per TRX only

� GLOBAL Quality of service INDICATORS > RTCH > Established phase

�TCAHCDRTR: TRX TCH drop rate due to radio problem

�TCTRTCDTR: TRX TCH drop rate due to TransCoder reported problem

�TCHOCDTR: TRX TCH drop rate due to HO failure


1.107

Alerting/Connection phase: TCH drop


� Find a TCH drop, find the cause

Can you tell if it is occurring during the

communication phase?

� Find a TCH drop due to handover, extract the call

� Find a TCH drop due to BSS problem, extract the call, identify PCM, CIC

� As 3, next case

Any remark?

2.3 Typical call failures TCH phase - exercise

Time allowed:

15 minutes


1.108

TYPICAL CALL FAILURES: summary

call stagecall stagecall stagecall stage A interfaceA interfaceA interfaceA interface cause cause cause cause fieldfieldfieldfield related related related related problemproblemproblemproblem

radio radio radio radio linklinklinklinkestablishmentestablishmentestablishmentestablishment

no messageno messageno messageno message ---- ---- SDCCH congestionSDCCH congestionSDCCH congestionSDCCH congestion---- radio radio radio radio problemproblemproblemproblem---- dummy dummy dummy dummy rachrachrachrach

SDCCH phaseSDCCH phaseSDCCH phaseSDCCH phase Clear Clear Clear Clear RequestRequestRequestRequest ---- radio interface radio interface radio interface radio interface failurefailurefailurefailure---- radio interface radio interface radio interface radio interface failurefailurefailurefailure---- O&M interventionO&M interventionO&M interventionO&M intervention

---- radio radio radio radio problemproblemproblemproblem---- BSS system HW/SW BSS system HW/SW BSS system HW/SW BSS system HW/SW pbpbpbpb---- recovery/operatorrecovery/operatorrecovery/operatorrecovery/operator

TCH TCH TCH TCH assignmentassignmentassignmentassignment Assignment Assignment Assignment Assignment FailureFailureFailureFailure ---- no radio no radio no radio no radio resource resource resource resource avalaibleavalaibleavalaibleavalaible---- Radio Interface Radio Interface Radio Interface Radio Interface FailureFailureFailureFailure

---- TCH congestionTCH congestionTCH congestionTCH congestion---- Radio Radio Radio Radio problemproblemproblemproblem

Alerting/connectionAlerting/connectionAlerting/connectionAlerting/connectioncall call call call establishedestablishedestablishedestablished

Clear Clear Clear Clear RequestRequestRequestRequest ---- radio interface radio interface radio interface radio interface failurefailurefailurefailure---- radio interface message radio interface message radio interface message radio interface message failurefailurefailurefailure---- equipment equipment equipment equipment failurefailurefailurefailure---- O&M interventionO&M interventionO&M interventionO&M intervention---- radio interface radio interface radio interface radio interface failurefailurefailurefailure----preemptionpreemptionpreemptionpreemption

---- radio radio radio radio problemproblemproblemproblem---- HO HO HO HO failure failure failure failure w/o w/o w/o w/o reversionreversionreversionreversion---- Transcoder Transcoder Transcoder Transcoder failurefailurefailurefailure---- operator operator operator operator action/recoveryaction/recoveryaction/recoveryaction/recovery---- BSS system HW/SW BSS system HW/SW BSS system HW/SW BSS system HW/SW pbpbpbpb---- preemptionpreemptionpreemptionpreemption

2.3 Typical call failures summary

B8 (See comments)

NewB8 New LAPD counter to analyze the cause of call establishment failures

� When the BSC is congested on the downlink, some messages are discarded. This may result for example in call establishment failures, loss of paging messages or delay in handover procedures.

A new LapD counter that indicates the time a LapD link is congested is created to analyze the cause of a degraded quality of service. This counter is implemented in type 7 and thus is only available in a detailed measurement campaign.

� Counter: L1.18: TIME_LAPD_CONG

� Definition: Time in seconds during which the LapD link is congested in transmission in the BSC.

B8



2 GLOBAL INDICATORS

2.4 Description of global indicators


1.110

2.4 Description of global indicatorsrecall

� Global Indicators are

� A set of indicators selected by Alcatel

� Useful to monitor the overall network

� What are the user and or system impacts if a GI is bad?


1.111

� SDCCH CONGESTION rate: may have impact for subscriber

� Call setup failure only after 3 subsequent congestions

� If not, only some extra delay for call establishment

� (less than 1 second) without immediate_assign_reject

� Can be longer with reject (but usually short values are used for call request)

2.4 Description of global indicatorsSDCCH congestion rate

INDICATOR

(G)

SDCCH ASSIGN CONG FAIL RATE

DEFINITION Rate of SDCCH not allocated during radio link establishment procedure due to congestion on the Air

interface

FORMULA B7.2 Σcell

(MC04) / SDCCH ASSIGN REQUESTS

THRESHOLD > 5%

COMMENT Check SDCCH Erlang : if not critical, SDCCH availability/allocation problem, or HO access on a

nearby cell side effect or interference on the carrier handling SDCCH (the last 2 can lead to high

rate of « phantom RACH »)

REF NAME SDNACGR UNIT %

� (G) means that the indicator is Global, i.e. it is important to provide it at a Network level.

INDICATOR SDCCH ASSIGN REQUESTS

DEFINITION Number of SDCCH seizure requests during radio link establishment procedureFORMULA B7.2 Σcell (MC148 + MC04)

THRESHOLD

COMMENT This includes requests rejected due to congestion on SDCCHREF NAME SDNARQN UNIT Number


1.112

DESCRIPTION OF GLOBAL INDICATORS

� SDCCH CONGESTION rate

2.4 Description of global indicatorsSDCCH congestion rate


� GLOBAL Quality of service INDICATORS > SDCCH > Assignment phase

� SDNACGR: SDCCH assignment failure rate due to congestion (Global)


1.113

� SDCCH DROP rate

� User impact: call setup failure

2.4 Description of global indicatorsSDCCH drop rate

INDICATOR

(G)

SDCCH DROP RATE

DEFINITION Rate of dropped SDCCH (SDCCH is established for any transaction OC, TC, LU,etc.)

FORMULA B7.2 Σcell

(MC138 + MC07 + MC137) / SDCCH ASSIGN SUCCESS

THRESHOLD > 4%

COMMENT Drop radio + Drop HO + Drop BSS

REF NAME SDCDR UNIT %

� In a dense network SDCCH drop rate should be lower than 1%. Indeed the probablity to drop a radio link when the MS is on SDCCH is less than on TCH since the SDCCH phase is shorter (less than 5 seconds) than TCH phase (several tens of seconds).

INDICATOR SDCCH ASSIGN SUCCESS

DEFINITION Total number of SDCCHs successfully seized by mobile during radio link establishmentprocedure

FORMULA B7.2 Σcell (MC01 + MC02)

THRESHOLD

COMMENTREF NAME SDNASUN UNIT Number


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� TCH ASSIGN UNSUCCESS rate:

� congestion

� radio problem

� BSS problems

2.4 Description of global indicatorsTCH assign unsuccess rate

INDICATOR

(G)

TCH ASSIGN UNSUCCESS RATE

DEFINITION Rate of unsuccessful RTCH seizures for normal assignment purpose (congestion + HO&radio

failures)

FORMULA B7.2 (TCH ASSIGN REQUESTS – TCH ASSIGN SUCCESS) / TCH ASSIGN REQUESTS

THRESHOLD > 3%

COMMENT

REF NAME TCNAUR UNIT %

� In a dense network, the TCH assignment unsucess rate should be lower a 1%.

INDICATOR TCH ASSIGN REQUESTS

DEFINITION Number of TCH seizure requests for normal assignment procedureFORMULA B7.2 Σ

cell (MC703 + MC812)

THRESHOLD

COMMENT This includes requests rejected due to congestionIn B7 : MC703 = MC16 (B6) but per TRXIn B7.1 : MC812 = MC612 (B6)In B7.2 : MC812 = [MC612(B6)]+[Congestion on Abis(C612e)]Congestion on Abis in restriction in B7.2, so finally MC812 = MC612 (B6)

REF NAME TCNARQN UNIT Number

INDICATOR TCH ASSIGN SUCCESS

DEFINITION Number of TCHs successfully seized by the MS for normal assignment procedureFORMULA B7.2 Σ TRX (MC718)

THRESHOLD

COMMENT MC718 is new in B7.MC718 = MC18 (B6) but per TRX.So indicator extended per TRX in B7

REF NAME TCNASUN UNIT Number


1.115

� GLOBAL RADIO CONGESTION LEVEL (TCH congestion rate)

� Subscriber impact: call setup failure

� More a management indicator: % of network which has congestion

S2: GLOBAL 2.4 Description of global indicatorsGlobal radio congestion level

INDICATOR

(G)

GLOBAL RADIO CONGESTION LEVEL

DEFINITION Global radio congestion level : number or rate of cells recurrently congested

FORMULA B7.2 COUNT_OF_CELLS (AVERAGE (MAX (TCH ASSIGN FAIL CONG RATE)) > 2%))

THRESHOLD According to operator

COMMENT This indicator reports the global radio congestion rate on the network. We define a specific

indicator counting the number of cells that are in congestion in a recurrent manner.

MAX (TCH ASSIGN FAIL CONG RATE) : is the peak of failures due to congestion observed

during the period (the day normally). See the definition of TCH ASSIGN FAIL CONG RATE in the

Quality of Service chapter)

AVERAGE : is an averaging function of the blocking rate over the selected period, that is over BH

of days for a week, or over BH of weeks for a month

COUNT_OF_CELL : is a function counting the number of cells for which condition between () is

respected.

The number of cells can be used as indicator, or the rate of cells over the total number of cells in the

network or area.

REF NAME QSCGR UNIT Number

� This counter intends to give a measurement of the TCH congestion of the whole network.

� It is implemented on the Alcatel tools but other indicators can be defined.


1.116

� CALL DROP rate: The most important indicator

� Used with call setup success rate to compare PLMN (GSM and otherone)

� Subscribers impact: call drop!!

2.4 Description of global indicatorsCall drop rate

INDICATOR

(G)

CALL DROP RATE

DEFINITION Rate of dropped calls (system + radio+ HO + preemption) over the total amount of calls with a

successful end

FORMULA B7.2 Σcell (MC621 + MC14c + MC736 + MC739 + MC921c) / TCH SUCCESS END

THRESHOLD > 4%

COMMENT Drop system + Drop radio + Drop HO + Drop preemption

TCH drops occurring after successful assignment but before speech connection are considered as

call drops even if from the customer point of view it is a call setup failure

MC739, MC736 and MC621 derive from B6 counters C139, C136 and C21. These new counters

are per TRXMC921c is new in B7.2

REF NAME QSCDR UNIT %

� In a dense network, the Call Drop Rate should be lower than 2%. It should even go down to 1% or less in case Slow Frequency Hopping is used.

� The RTCH drop rate is defined below:

� The TRX TCH drop radio rate is defined below:

INDICATOR GLOBAL TCH DROP

DEFINITION Rate of TCHs dropped (system + radio + handover + preemption) over the total amount ofcalls established in the cell

FORMULA B7.2 Σcell (MC14c + MC739 + MC736 + MC621+ MC921c) / TCH SUCCESS BEGIN

THRESHOLD > 3%COMMENT Drop System + Drop radio + Drop HO + Drop preemption

Indicator relevant at cell level mostly.MC739, MC736 and MC621 derive from B6 counters C139, C136 and C21. These new

counters are per TRXMC921c is new in B7.2

REF NAME QSTCCDR UNIT %

INDICATOR TRX TCH DROP RADIO RATE

DEFINITION Rate of TCHs dropped due to radio problems, per TRXFORMULA B7.2 (MC736) / TCH SUCCESS

THRESHOLD > 3%COMMENT New in B7

MC736 derives from B6 counters C136. This new counter in B7 is per TRX.Indicator only per TRX because intracell handovers are taken into account

REF NAME TCAHCDRTR UNIT %


1.117

� CALL SETUP SUCCESS rate: the second most important indicator

� Used to compare PLMN

� Subscriber: call not established at the first attempt

� Beware: call setup failures due to a lack of coverage are not taken into account in this indicator!!

� No way to quantify them (as there is no initial access)

2.4 Description of global indicatorsCall setup success rate

INDICATOR

(G)

CALL SETUP SUCCESS RATE (BSS view)

DEFINITION Rate of calls going until TCH successful assignment, that is not interrupted by SDCCH DROP

neither by Assignment failures

FORMULA B7.2 (1 – ( SDCCH DROP / SDCCH ASSIGN SUCCESS ) ) * (1 TCH ASSIGN UNSUCCESS RATE)

THRESHOLD > 95%

COMMENT SDCCH assignment failures are not considered in CSSR as :

• ghost (spurious) RACH cannot be discriminated from a real access failure

• effect of re-attempts performed autonomously by the MS cannot be quantified

REF NAME QSCSSR UNIT %

� Ghost Racks which correspond to a valid establishment cause are not identified by the BSS. Therefore they can lead to a high SDCCH assignment failure rate if they are too numerous.

� As the end user is not impacted by this phenomenon if no SDCCH congestion is induced, the SDCCH assignment phase is not considered in the computation of the Call Setup Success rate provided by Alcatel tools.

� In a dense network, the Call Setup Success Rate should be greater than 98%.

� The SDCCH congestion rate should also be considered to have a complete picture of Call Setup efficiency.


1.118

� 1 call success =

� 1 call successfully established

� Without any call drop

2.4 Description of global indicatorsCall success rate

INDICATOR

(G)

CALL SUCCESS RATE (BSS view)

DEFINITION Rate of calls going until normal release , that is not interrupted by SDCCH DROP, neither byAssignment Failures nor by CALL DROP

FORMULA B6.2 (CALL SETUP SUCCESS RATE) * (1 – CALL DROP RATE)

THRESHOLD < 92%

COMMENT

REF NAME QSCCR UNIT %

� In a dense network, the Call Setup Success Rate should be greater than 97%.


1.119

� CALL SETUP SUCCESS rate

� CALL SUCCESS rate

2.4 Description of global indicatorsCall (setup) success rate


� GLOBAL Quality of service INDICATORS > Call statistics > Call success

� QSCSSR: Call setup success rate (Global)

� QSCCR: Call success rate (Global)


1.120

2.4 Description of global indicatorsHandover cause distribution

� Indicator aiming at measuring the efficiency of planning /optimization

INDICATOR

(G)

HO CAUSE DISTRIBUTION

DEFINITION Distribution of Handover attempts by cause X : UL/DL Qual, UL/DL Lev, UL/DL Interference,

Distance, Better Cell, Interband, Micro cells HO, Concentric cell, Traffic, AMR, TFO causes.

FORMULA B7.2 Σ cell

(MC67w or MC785x or MC586y or MC10zz or MC447 or MC461)

Σcell

(MC67all + MC785all + MC586all + MC10all + MC447 + MC461)

MC67all = MC671+MC672+MC673+MC674+MC675+MC676+MC677+MC678+MC679

+MC670

MC785all = MC785a + MC785d + MC785e + MC785f (microcell)

MC586all = MC586a + MC586b + MC586c (concentric)

MC10all = MC1040 + MC1044 + MC1050

THRESHOLD Quality DL > 10%, Qual UL > 10%, Level UL > 20%, Level DL > 20%

Interf UL > 5%, Interf DL > 5%, Better Cell < 30%

COMMENT

REF NAME HCSTBPBR, HCCCELVDR, HCCCELVUR, HCCCBCPR,

HCSTEDIR, HCSTEIFDR, HCSTELVDR, HCSTEQLDR,

HCSTBDRR, HCMBBCPR, HCMCEBSR, HCMCELVDR,

HCMCBCPR, HCMCELVUR, HCSTEMIR, HCSTEIFUR,

HCSTELVUR, HCSTEQLUR, HCSTAMR, HCSTBTFR

UNIT %


1.121

2.4 Description of global indicatorsHandover standard cause distribution

� Indicator aiming at measuring the efficiency of planning / optimization

� Interesting for comparing HO distribution after concentric or micro cell implementation

INDICATOR

(G)

DISTRIBUTION HO CAUSE STANDARD

DEFINITION Distribution of Handover attempts by standard cause : Power Budget, quality too low, level too low,

high interference and MS-BTS distance too long.

FORMULA B7.2

Σ cell ( (MC67x) / GLOBAL HO CAUSE STANDARD)

MC67x = MC670 or MC672 or MC671 or MC673 or MC676 or MC677 or MC678 or MC674 or

(MC670+MC672) or (MC671+MC673) or (MC676+M677)

THRESHOLD

COMMENT

REF NAME HCSTEIFDSR, HCSTEIFUSR, HCSTEIFSR, HCSTELVDSR,

HCSTELVUSR, HCSTELVSR, HCSTEQLDSR,

HCSTEQLUSR, HCSTEQLSR, HCSTBPBSR, HCSTEDISR

UNIT %

� The Global HO cause standard indicator is defined as below:

� where:

� MC670: Number of handover attempts cause 2: "uplink quality too low"

� MC672: Number of handover attempts cause 4: ”downlink quality too low"

� MC671: Number of handover attempts cause 3: "uplink level too low"

� MC673: Number of handover attempts cause 5: "downlink level too low"

� MC676: Number of handover attempts cause 15: "too high uplink interference level"

� MC677: Number of handover attempts cause 16: "too high downlink interference level"

� MC678: Number of handover attempts cause 12: "too low power budget"

� MC674: Number of handover attempts cause 6: "MS-BTS distance too long"


1.122

2.4 Description of global indicatorsHandover cause distribution

� HANDOVER CAUSE rates


� Handover statistics INDICATORS > Handover causes

� HCXXYYYYR: Rate of specific HO cause xxyyyy versus all HO causes (Global)

� where XX = ST (standard) or MC (micro cell) or CC (concentric cell) or MB (multi band)

� and YYYY is specific to the cause


1.123

� Global success rate of Outgoing HO

� Success rate of execution of Outgoing HO

2.4 Description of global indicatorsOutgoing handover success rate

INDICATOR

(G)

OUTGOING HO SUCCESS RATE

DEFINITION Rate of successful outgoing external and internal intercell SDCCH and TCH handovers

FORMULA B7.2 Σcell (MC646 + MC656) / Σcell (MC645a + MC655a)

THRESHOLD < 90%

COMMENT This indicator includes preparation and execution.

REF NAME HOORSUR UNIT %

INDICATOR

(G)

EFFICIENCY OF OUTGOING HANDOVER EXECUTION

DEFINITION Rate of successful outgoing external and internal intercell SDCCH and TCH handovers

FORMULA B7.2 Σcell (MC646 + MC656) / Σcell (MC650 + MC660)

THRESHOLD < 90%

COMMENT This indicator takes into account HO execution only (not ho preparation).

REF NAME HOOREFR UNIT %

� Global Outgoing HO success rate: represents the global efficiency ot the outgoing handovers performed from one cell to any of its neighboring cells (same BSS or not).

� Efficiency of Outgoing HO execution: represents the efficiency of the channel change procedure during outgoing handovers performed from one cell to any of its neighboring cells (same BSS or not). It does not take into account the HO failures that can occur during the preparation phase when the new channel is being selected and activated.

� From B7 MC645A replaces MC645 of B6.


1.124

� Global success rate of Incoming HO

� Success rate of execution of Incoming HO

2.4 Description of global indicatorsIncoming handover success rate

INDICATOR

(G)

INCOMING HANDOVER SUCCESS RATE

DEFINITION Rate of successful incoming external and internal intercell SDCCH and TCH handovers.

FORMULA B7.2 Σcell (MC642 + MC652) / Σcell(MC820 + MC830)

THRESHOLD < 90%

COMMENT

REF NAME HOIRSUR UNIT %

INDICATOR

(G)

EFFICIENCY OF INCOMING HANDOVERS

DEFINITION Rate of successful incoming external and internal intercell SDCCH and TCH HOs

FORMULA B7.2 Σcell (MC642 + MC652) / Σcell (MC821 + MC831)

THRESHOLD < 90%

COMMENT Excluding congestion failures and BSS preparation failures from requests.

REF NAME HOIREFR UNIT %

� Global Incoming HO success rate: represents the global efficiency of the incoming handovers performed to one cell from any of its neighboring cells (same BSS or not).

� Efficiency of Incoming HO execution: represents the efficiency of the channel change procedure during incoming handovers performed to one cell from any of its neighboring cells (same BSS or not). It does not take into account the HO failures that can occur during the preparation phase when the new channel is being selected and activated.


1.125

� The highest, the best is the cell

� But the traffic handled is not taken into account

2.4 Description of global indicatorsCall quality factor absolute

INDICATOR(G)

CELL QUALITY FACTOR ABSOLUTE

DEFINITION Indicator summarizing the cell behavior and allowing the operator to sort out cell for investigation.This indicator is based on failure events. For each part of the indicator,twothresholds are used: Topt and TQoS. TQoS is the QoS warning threshold (e.g. above orbelowthe threshold, a warning is generated on the cell. Topt + TQoS is the optimal valuethat should be acheived. Each part as a weighting factor (WF) according to the impact on the subscriber’s point of view.

investigation. This indicator is based on failure events. For each part of the indicator, two

FORMULA B6.2 ((1 – SDCCH CONGESTION rate) - TQoS)/ Topt * WF+ (CALL SETUP SUCCESS rate - TQoS)/ Topt *WF+ ((1 – CALL DROP rate - TQoS)/ Topt * WF+ (OUTGOING HO SUCCESS rate - TQoS)/ Topt * WF+ ((1 – HO QUALITY rate - TQoS)/ Topt * WF

THRESHOLD SDCCH CONGESTION rate : TQoS = 0.97, Topt = 0.03, WF = 0.1CALL SETUP SUCCESS rate : TQoS = 0.9, Topt = 0.09, WF = 0.2CALL DROP rate : TQoS = 0.96, Topt = 0.04, WF = 0.3OUTGOING HO SUCCESS rate : TQoS = 0.85, Topt = 0.12, WF = 0.15HO QUALITY rate : TQoS = 0.85, Topt = 0.1, WF = 0.25

COMMENTREF NAME QSCQAR UNIT %

� This counter intends to compute for every cell of the network a global indicator taking into account the major causes of bad Quality of Service.

� Each cause is weighted according to the impact on the end user.


1.126

� For optimization

� Try to improve cells with the worst CQFR

2.4 Description of global indicatorsCall quality factor relative

INDICATOR

(G)

CELL QUALITY FACTOR RELATIVE

DEFINITION This indicator is the Cell Quality Factor Absolute weighted by the cell traffic. Investigation shouldbe done in priority on the cell having a high rate of failures with high traffic (the traffic is the rate of

traffic handled by the cell over the total network traffic – traffic is TCH seizure attempts)

FORMULA B7.2 CQFA * ((MC15a + MC15b + MC703)cell / (MC15a + MC15b + MC703)network)

THRESHOLD N/A

COMMENT

REF NAME QSCQRR UNIT %

� Normalizing the previous Cell Quality Factor Absolute by the traffic of the cell will allow to compare the QoS of the cell between each other and raise the list of top worst cells candidate for analysis.

� From B7, MC703 replaces MC16 of B6.


1.127

� Management indicator, maintenance oriented, assessing

� Quantity of stability problems

� Reaction time to problems

2.4 Description of global indicatorsNetwork TCH availability

INDICATOR

(G)

NETWORK (TCH) AVAILABILITY

DEFINITION Rate of TCHs able to carry traffic (upon the total number of traffic channels)

FORMULA B7.2 (Σcell

(MC250) / #Available TCH)

THRESHOLD < 95%

COMMENT #Available TCH : according to channel configuration

REF NAME TCAVAR UNIT %


1.128

� GLOBAL INDICATORS

2.4 Description of global indicatorsExercise

IndicatorIndicatorIndicatorIndicator valuevaluevaluevalue OK ?OK ?OK ?OK ? ImpactImpactImpactImpact

SDCCH congestionSDCCH congestionSDCCH congestionSDCCH congestion 10 %10 %10 %10 % NOKNOKNOKNOK difficulties to difficulties to difficulties to difficulties to establish callestablish callestablish callestablish call

Call dropCall dropCall dropCall drop 5 %5 %5 %5 %

Call Call Call Call successsuccesssuccesssuccess 95 %95 %95 %95 %

Efficiency of Efficiency of Efficiency of Efficiency of outgoing HOoutgoing HOoutgoing HOoutgoing HO 91 %91 %91 %91 %

Network TCH Network TCH Network TCH Network TCH availabilityavailabilityavailabilityavailability 94 %94 %94 %94 %

TCH TCH TCH TCH assignment assignment assignment assignment failurefailurefailurefailure 2,4 %2,4 %2,4 %2,4 %

Call dropCall dropCall dropCall drop 2,3 %2,3 %2,3 %2,3 %

SDCCH dropSDCCH dropSDCCH dropSDCCH drop 2 %2 %2 %2 %

HO cause distributionHO cause distributionHO cause distributionHO cause distribution(ratio of (ratio of (ratio of (ratio of better better better better cell)cell)cell)cell)

45 %45 %45 %45 %

Call Call Call Call successsuccesssuccesssuccess 88 %88 %88 %88 %

SDCCH dropSDCCH dropSDCCH dropSDCCH drop 1 %1 %1 %1 %

Time allowed:

10 minutes



2 GLOBAL INDICATORS

2.5 Traps and restrictions of global indicators


1.130

2.5 Traps and restrictions of global indicatorsObjective

� Beaware of traps and restrictions about some global indicators

� So as to be able to provide a reliable interpretation


1.131

2.5 Traps and restrictions of global indicatorsCall set-up success rate / Call drop rate

� CALL SETUP SUCCESS

� The radio link establishment failure is not taken into account, because:

� most of failures during RLE are due to ghost RACH

� the MS is attempting MAX_RETRANS+1 times before giving up

� difficult to assess subscriber's impact, anyhow very low

� CALL DROP

� For BSS, the last stage is considered as established, although it is not the cause from a user point of view

� If a TCH drop occurs during this phase

� for the user, it is a setup failure

� for the OMC-R indicators, counted as a call drop


1.132

2.5 Traps and restrictions of global indicatorsCall duration

IMPACT OF CALL DURATION

� The longest a call is, the highest the risk to have a drop is

� If statistics are done on abnormally long or short calls, the result can be less accurate

� Typical case: drive test

� Typical call duration: 80/90 seconds in most of European countries


1.133

2.5 Traps and restrictions of global indicatorsMobility

IMPACT OF MOBILITY

� Most of drop problems are due to mobility

� Usually 2/3 of calls are static (no HO will be done)

� For example, if 40 drops are observed for 1000 calls

� 40/1000 = 4% of global call drop

� but most of call drops are generated by "moving calls"

� 40/(1000*1/3) = 40/333 = 12 % of call drop rate for moving call

� 0 % for static call

� Typical trap when comparing drive tests results with OMC-R statistics


1.134

2.5 Traps and restrictions of global indicatorsExercise

� TRAPS AND RESTRICTIONS OF GLOBAL INDICATORS: CaseCaseCaseCase conclusionconclusionconclusionconclusion OK ?OK ?OK ?OK ? whywhywhywhy

global call drop : 2%global call drop : 2%global call drop : 2%global call drop : 2% for 1 call of 20 for 1 call of 20 for 1 call of 20 for 1 call of 20 mnmnmnmn,,,,

TheTheTheThe riskriskriskrisk of dropof dropof dropof drop isisisis 2% 2% 2% 2% NOKNOKNOKNOK The callThe callThe callThe call duration is higher thanduration is higher thanduration is higher thanduration is higher than thethethethe average average average average

In 1 BSS, In 1 BSS, In 1 BSS, In 1 BSS, some some some some transcoderstranscoderstranscoderstranscoders areareareare

faultyfaultyfaultyfaulty : as : as : as : as soonsoonsoonsoon as TCHs areas TCHs areas TCHs areas TCHs are

establishedestablishedestablishedestablished onononon these TCsthese TCsthese TCsthese TCs,,,, theytheytheythey are are are are

lostlostlostlost

The call The call The call The call setup setup setup setup successsuccesssuccesssuccess

rate rate rate rate indicator indicator indicator indicator will will will will bebebebe

increasedincreasedincreasedincreased due to due to due to due to thisthisthisthis

problemproblemproblemproblem

In 1 network, drive test areIn 1 network, drive test areIn 1 network, drive test areIn 1 network, drive test are

showinga generalshowinga generalshowinga generalshowinga general call drop of 7%. call drop of 7%. call drop of 7%. call drop of 7%.

The OMCThe OMCThe OMCThe OMC----R call dropR call dropR call dropR call drop indicator is indicator is indicator is indicator is

givinggivinggivinggiving 2.1%.2.1%.2.1%.2.1%.

The OMCThe OMCThe OMCThe OMC----RRRR indicator indicator indicator indicator

is erroneousis erroneousis erroneousis erroneous (drive(drive(drive(drive

testtesttesttest isisisis thethethethe realityrealityrealityreality))))

In 1 network, the global callIn 1 network, the global callIn 1 network, the global callIn 1 network, the global call setup setup setup setup

success success success success isisisis 92 %92 %92 %92 %

For For For For moving callsmoving callsmoving callsmoving calls, call, call, call, call

setup setup setup setup success success success success will will will will bebebebe

about 76 %about 76 %about 76 %about 76 %

In a In a In a In a pedestrianpedestrianpedestrianpedestrian zone, 80 % ofzone, 80 % ofzone, 80 % ofzone, 80 % of callscallscallscalls

are are are are staticstaticstaticstatic

TheTheTheThe measuredmeasuredmeasuredmeasured call dropcall dropcall dropcall drop isisisis 1,7 %1,7 %1,7 %1,7 %

For taxi,For taxi,For taxi,For taxi, calldonecalldonecalldonecalldone in in in in

Taxi inTaxi inTaxi inTaxi in thisthisthisthis zonezonezonezone willwillwillwill

be be be be dropped dropped dropped dropped atatatat 5.1 %5.1 %5.1 %5.1 %

Time allowed:

10 minutes



2 GLOBAL INDICATORS

2.6 Global indicators interpretation


1.136

2.6 Global indicators interpretation Exercise 1

� Is this network OK?

N a m eN a m eN a m eN a m e v a l u ev a l u ev a l u ev a l u e

S D C C H c o n g e s t i o nS D C C H c o n g e s t i o nS D C C H c o n g e s t i o nS D C C H c o n g e s t i o n 1 %

S D C C H d r o pS D C C H d r o pS D C C H d r o pS D C C H d r o p 3 %

T C H T C H T C H T C H a s s ig n m e n t a s s ig n m e n t a s s ig n m e n t a s s ig n m e n t f a i l u r ef a i l u r ef a i l u r ef a i l u r er a t er a t er a t er a t e

2 %

C a l l d r o pC a l l d r o pC a l l d r o pC a l l d r o p 1 %

C a l l C a l l C a l l C a l l s e t u p s e t u p s e t u p s e t u p s u c c e s s r a t es u c c e s s r a t es u c c e s s r a t es u c c e s s r a t e 9 6 %

C a l l C a l l C a l l C a l l s u c c e s s r a t es u c c e s s r a t es u c c e s s r a t es u c c e s s r a t e 9 4 %

E f f i c i e n c y o f E f f i c i e n c y o f E f f i c i e n c y o f E f f i c i e n c y o f o u t g o i n go u t g o i n go u t g o i n go u t g o i n gH OH OH OH O

9 2 %

E f f i c i e n c y o f E f f i c i e n c y o f E f f i c i e n c y o f E f f i c i e n c y o f i n c o m in gi n c o m in gi n c o m in gi n c o m in gH OH OH OH O

9 3 %

H O c a u s e d i s t r i b u t io nH O c a u s e d i s t r i b u t io nH O c a u s e d i s t r i b u t io nH O c a u s e d i s t r i b u t io nb e t t e r / l e v e l / q u a l i t yb e t t e r / l e v e l / q u a l i t yb e t t e r / l e v e l / q u a l i t yb e t t e r / l e v e l / q u a l i t y

7 0 / 2 0 / 1 0

N e tw o r k T C HN e tw o r k T C HN e tw o r k T C HN e tw o r k T C Ha v a i l a b i l i t ya v a i l a b i l i t ya v a i l a b i l i t ya v a i l a b i l i t y

9 8 %

Time allowed:

5 minutes


1.137


� Can one say that :

� all indicators are OK?

� the coverage of the network is 95%?

� the call success of all the cells are 95% (minimum)? N a m eN a m eN a m eN a m e v a l u ev a l u ev a l u ev a l u e

S D C C H c o n g e s t i o nS D C C H c o n g e s t i o nS D C C H c o n g e s t i o nS D C C H c o n g e s t i o n 5 %

S D C C H d r o pS D C C H d r o pS D C C H d r o pS D C C H d r o p 2 %

T C H a s s i g n m e n t f a i l u r eT C H a s s i g n m e n t f a i l u r eT C H a s s i g n m e n t f a i l u r eT C H a s s i g n m e n t f a i l u r er a t er a t er a t er a t e

1 %

C a l l d r o pC a l l d r o pC a l l d r o pC a l l d r o p 1 %

C a l l s e t u p s u c c e s s r a t eC a l l s e t u p s u c c e s s r a t eC a l l s e t u p s u c c e s s r a t eC a l l s e t u p s u c c e s s r a t e 9 7 %

C a l l s u c c e s s r a t eC a l l s u c c e s s r a t eC a l l s u c c e s s r a t eC a l l s u c c e s s r a t e 9 5 %

E f f i c i e n c y o f o u t g o i n gE f f i c i e n c y o f o u t g o i n gE f f i c i e n c y o f o u t g o i n gE f f i c i e n c y o f o u t g o i n gH OH OH OH O

9 2 %

E f f i c i e n c y o f i n c o m i n gE f f i c i e n c y o f i n c o m i n gE f f i c i e n c y o f i n c o m i n gE f f i c i e n c y o f i n c o m i n gH OH OH OH O

9 2 %

H O c a u s e d i s t r i b u t i o nH O c a u s e d i s t r i b u t i o nH O c a u s e d i s t r i b u t i o nH O c a u s e d i s t r i b u t i o nb e t t e r / l e v e l / q u a l i t yb e t t e r / l e v e l / q u a l i t yb e t t e r / l e v e l / q u a l i t yb e t t e r / l e v e l / q u a l i t y

7 5 / 1 5 / 1 0

N e t w o r k T C HN e t w o r k T C HN e t w o r k T C HN e t w o r k T C Ha v a i l a b i l i t ya v a i l a b i l i t ya v a i l a b i l i t ya v a i l a b i l i t y

9 8

Time allowed:

5 minutes


1.138


� Results of field tests on a network

� Is the network better if QSCDR = 2%?

NameNameNameName valuevaluevaluevalue

SDCCH congestionSDCCH congestionSDCCH congestionSDCCH congestion

SDCCH dropSDCCH dropSDCCH dropSDCCH drop

TCHTCHTCHTCH assignment failureassignment failureassignment failureassignment failureraterateraterate

Call dropCall dropCall dropCall drop 4.6 %

CallCallCallCall setup successsetup successsetup successsetup success raterateraterate 92 %

CallCallCallCall successsuccesssuccesssuccess raterateraterate

EfficiencyEfficiencyEfficiencyEfficiency ofofofof outgoingoutgoingoutgoingoutgoingHOHOHOHO

EfficiencyEfficiencyEfficiencyEfficiency ofofofof incomingincomingincomingincomingHOHOHOHO

HO cause distributionHO cause distributionHO cause distributionHO cause distributionbetterbetterbetterbetter////levellevellevellevel////qualityqualityqualityquality

Network TCHNetwork TCHNetwork TCHNetwork TCHavailabilityavailabilityavailabilityavailability

Time allowed:

5 minutes



3. DETAILED INDICATORS


1.140

3 Detailed indicatorsSession presentation

� Objective: to be able to use the BSS - DEFINITION OF QUALITY OF SERVICE INDICATORS document in order to get some more detailed indicators of the Alcatel BSS

� Program:

3.1 Indicator reference name

3.2 Indicators classification




3.1 Indicator reference name


1.142

3.1 Indicator reference nameDescription

� each QOS indicator has a unique REFERENCE NAME of 10 characters

UnitFamily

Procedure Type Joker

Prefix Sub-type

mandatory

optional




3.2 Indicators classification


1.144

3.2 Indicators classification Main categories

� Classification in BSS - DEFINITION OF QUALITY OF SERVICE INDICATORS document

Control Channels

SCCP

TCH

SDCCH

Traffic load

Call statistics

RTCH

SDCCH

Global QoS

Couple of cells

SDCCH /TCHHO repartition

Intracell HO

Incoming HO

Outgoing HO

HO causes

Handover

statistics

Resource

availability

Multiband

Multilayer / MultibandNetwork

Concentric cells

Directed retry

Densification

techniques

GSM

indicators


1.145

3.2 Indicators classification SDCCH traffic

� Traffic Load and Traffic Model > SDCCH traffic

Estab

SDCCH Traffic

TrafficMT

TrafficMO

Loc. Update

IMSI Detach

Sup. Service

Call

LU Follow on

SMS

CallRe-Estab

Other

MSPenetration Rate

TrafficDual Band

ResourceOccupancy

SDCCHErlang

SDCCH MeanHolding TimeGlobal

Traffic

GlobalRequests

TrafficModel

HandoverNormalAssignment

NormalAssignment

Handover

� The Traffic model section includes indicators for:

– number of SDCCH connection requests and successses (Immediate Assignment, HO).

– distribution of SDCCH connection success (MO and MT connections versus all MO+MT connections, type of MO connections versus all MO connection types).

� The MS penetration rate section includes the indicator for:

– percentage of multiband MS SDCCH access (except LU) versus all MS SDCCH accesses.

� The Resource occupancy section includes indicators for:

– SDCCH traffic in Erlang.

– average duration in seconds of SDCCH channel usage.


1.146

3.2 Indicators classification TCH traffic

� Traffic Load and Traffic Model > TCH traffic

RTCH Traffic

Resource

Occupancy

TCHErlang

Full Rate

Erlang

Full RateAllocated

Full RateMean TCH

Time

Half RateErlang

Half RateAllocated

Half RateMean TCH

Time

Blocking Peak

Ratio ofHR Traffic

TCHMultiband

Occupancy

Traffic Model

REQUESTSAssign / HO / DR

SUCCESSAssign / HO / DR

HO PER CALL

REQUESTS

FR, DR, DR/EFR, AMR, DATA

Speech Version&

Channel Type

ALLOCATIONS

FR, HR, EFR, AMR, DATA

SUCCESSAMR / TFO

� The Speech Version and Channel Type section includes indicators for:

– distribution of TCH allocation requests (FR/DR/DR+EFR/AMR/DATA).

– distribution of TCH allocation successes (FR/DR/DR+EFR/AMR/DATA).

– rate of TCH AMR allocation successes.

– rate of TFO calls versus all speech calls.

� The Traffic model section includes indicators for:

– number of TCH connection requests and successes (Normal Assignment, HO, DR).

– rate of TCH allocation successes for HO+DR versus all TCH allocations (NA+HO+DR).

– number of HOs per call.

� The Resource occupancy section includes indicators for:

– RTCH traffic in Erlang (FR+HR, FR, HR, multiband).

– average duration in seconds of RTCH channel usage (FR+HR, FR, HR).

– number of TCH FR allocations and number of TCH HR allocations.

– rate of TCH HR allocations versus all TCH allocations (FR+HR).

– TCH peak of blocking (TCH congestion time).


1.147

3.2 Indicators classificationSCCP resource occupancy / Control channels traffic

� Traffic Load and Traffic Model > SCCP resource occupancy

� SCCP traffic in Erlang

� Traffic Load and Traffic Model > Control Channels traffic

� PCH channel load

� AGCH channel load

� RACH channel load


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3.2 Indicators classificationQoS SDCCH

� GLOBAL Quality of service > SDCCH

Drop BSS

SDCCH

Established

Phase

Drop Rate

Drop Radio Drop HO

Unsuccess

Congestion

Assignment Phase

/

Handover

Radio

FailureBSS Failure

Access Reject

Dynamic Allocation

B8

New B8

(See comments)

�The Assignment phase section includes indicators for the Radio Link Establishment procedure: � global SDCCH access failure rate. � specific SDCCH access failure rate per type of problem (SDCCH congestion, radio, BSS).� specific indicators for Dynamic SDCCH Allocation:

Stored Indicators (see Dynamic SDCCH Allocation in the Global Indicators section)DYTROFN.= MC800DYAHCATAN = MC801aDYAHCATMN = MC801bDYAHCASAN. = MC802aDYAHCASMN.= MC802bDYN = number of Dynamic timeslots (given by configuration file) = Cell_NB_DYNComputed indicatorsDYAHCATAR: average rate of busy TCH (FR of HR) allocated on dynamic SDCCH/8 timeslotsFormula: tdiv (DYAHCATAN,DYTROFN,0,0)DYAHCATMR: maximum rate of busy TCH (FR of HR) allocated on dynamic SDCCH/8 timeslotsFormula: tdiv (DYAHCATMN,DYTROFN,0,0)DYAHCASAR: average rate of busy SDCCH sub-channels allocated on the dynamic SDCCH/8timeslotsFormula: tdiv (DYAHCASAN,DYTROFN,0,0)Impact on existing Indicators: Apart of modification due to introduction of Dynamic SDCCH/8 timeslot, the general formula of these indicators are redesigned, to be simpler.TCRRDN, TCRROFN, TCAHCGUN, TCAVAR (removed as it is the same as TCTRAR), TCTRAVE, TCTRAR, TCTRTCE, SDAHCGUN, SDAVAR, SDRRDN, SDRROFN, SDTRAVE

�The Handover procedure section includes the indicator for the preparation of the SDCCH HO procedure: � rate of SDCCH HO failure due to SDCCH congestion

�The Established phase section includes indicators for SDCCH Phase: � global SDCCH drop rate.� specific SDCCH drop rate per type of problem (radio, HO, BSS).

B8


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3.2 Indicators classificationQoS RTCH

� GLOBAL Quality of service > RTCH

DirectedRetry

RTCH

Unsuccess

Assignment Phase/

Handover

Global RadioCongestion Level

Congestion

RadioFailure

BSSFailure

EstablishedPhase

Drop rate

Drop Radio

Drop BSS

Drop HO

Preemption

PreemptionPhase

PCI =1 PVI =1

Requests

Allocationwith / withoutPreemption

Failure

Success

Success

QueuingPhase

Queue Length

AssignQueuing Fail

AssignQueued

& Reject

Queued

Success

Queue Full

HigherPriority

Timeout

AssignQueued

NormalAssign.

�The Assignment phase section includes indicators for the TCH Normal Assignment procedure: � global RTCH assignment failure rate (called unsuccess rate).� specific RTCH assignment failure rate per type of problem (RTCH congestion, radio, BSS).� global radio congestion level (number of cells congested in the network).

�The Handover procedure section includes indicators for the global HO procedure (intracell+intercell internal + intercell external): � rate of RTCH incoming HO failure due to RTCH congestion.� specific RTCH outgoing HO failure rate per type of problem (congestion, radio - Reversion Old Channel, radio drop, BSS).


1.150

3.2 Indicators classificationQoS call statistics

� GLOBAL Quality of service > Call statistics

Call Statistics

Call Success

Call SetupSuccess Rate

CallSuccess Rate

Cell QualityFactor Absolute

Cell QualityFactor Relative

Call Drop

Call Drop Rate

Drop Radio Drop BSSDrop HO

Transcoder Failure

BSS Internal Failure

Call DropEnd User Rate

Preemption

�The Call Drop section includes indicators for the TCH Phase: � global call drop rate.� specific call drop rate per type of problem (radio, HO, BSS int., TransCoder, preemption).

�The Call Success section includes indicators for the global call procedure (speech): � rate of call setup success.� rate of call success.� global cell quality factor.


1.151

� Handover STATISTICS > Handover causes

3.2 Indicators classificationHandover causes

Handover causes

HO causes

All HO

cause distribution

Outgoing HO Incoming HO

HO standardcause

distribution

HO cause category

distribution

HO causes per Adjacency

HO cause category

distribution

B8

Fast traffic HO taken into account

New type of counter for dual band HO

(See comments)

New B8

�The Handover causes section includes indicators of HO causes distribution corresponding to outgoing handovers relating to a cell: � distribution of HO causes taking into account all possible HO causes (quality UL, level DL, distance, power budget, concentric cell cause, micro cell cause, traffic, etc.).� distribution of HO standard causes taking into account only HO standard causes (quality UL, quality DL, level UL, level DL, interference UL, interference DL, distance, power budget).

�The Handover causes per adjacency section includes indicators of HO causes distribution corresponding to outgoing and incoming handovers relating to a couple of serving/target cells:

� distribution of HO cause categories taking into account 3 categories (emergency [quality, level, interference, distance, power budget]), better condition [power budget, capture], traffic, forced directed retry).

B8: Introduction of C449 (type 6) in type 110 (as MC449) improves the result of all HO cause Indicators:C449 = MC449 = number of handover attempts with cause 28 (Fast traffic handover)The Indicator TOTALHO (HCN) is impacted as well as the following indicators:

HCSTBPBR, HCCCR, HCSTEDIR, HCSTEDMR, HCSTIFDR, HCSTLVDR, HCSTQLDR, HCSTEIFR, HCSTELVR, HCMCR, HCSTEQLR, HCSTIFUR, HCSTLVUR, HCSTQLUR, HCNTBDR, HCSTBTFR, HCSTAMR, HCSTAMFR, HCSTAMHR, HCSTBTRFR

B8: Introduction of a new type of counter (Type 32: Change of frequency band measurements)

Type 32 is defined as Standard and provides information to observe handovers between different frequency bands.C403a = NB_INC_EXT_TCH_HO_NEW_BAND_ATPT = Number of incoming external TCH (in HR or FR usage) handover attempts including a change of the (TCH) frequency band.C403b = NB_INC_EXT_TCH_HO_NEW_BAND_SUCC = Number of incoming external TCH (in HR or FR usage) handover successes including a change of the (TCH) frequency band.C404a = NB_OUT_EXT_TCH_HO_NEW_BAND_ATPT = Number of outgoing external TCH (in HR or FR usage) handover attempts including a change of the (TCH) frequency band.C404b = NB_OUT_EXT_TCH_HO_NEW_BAND_SUCC = Number of outgoing external TCH (in HR or FR usage) handoversuccesses including a change of the (TCH) frequency band.C420a = NB_INC_INT_TCH_HO_NEW_BAND_ATPT = Number of incoming internal TCH (in HR or FR usage) handover attempts including a change of the (TCH) frequency band.C420b = NB_INC_INT_TCH_HO_NEW_BAND_SUCC = Number of incoming internal TCH (in HR or FR usage) handover successes including a change of the (TCH) frequency band.C421a NB_OUT_INT_TCH_HO_NEW_BAND_ATPT = Number of outgoing internal TCH (in HR or FR usage) handover attempts including a change of the (TCH) frequency band.C421b NB_OUT_INT_TCH_HO_NEW_BAND_SUCC = Number of outgoing internal TCH (in HR or FR usage) handover successes including a change of the (TCH) frequency band.

B8


1.152

� Handover STATISTICS > Outgoing handovers

3.2 Indicators classificationOutgoing handovers

Failure With Reversion

Call Drop Rate

Efficiency

Preparation Success Rate

Intra-BSC


Call Drop Rate

Efficiency


External

Call Drop Rate

Efficiency

Success Rate

Intra-BSC & External

Outgoing HO

B8

New B8 New LAPD counter to analyze the cause of delay in HO procedures

�The Outgoing Intra BSC intercell section includes indicators corresponding to the efficiency of outgoing intercell internal handovers relating to a cell (serving):

� efficiency ot the preparation phase (target TCH allocation) of the outgoing handovers performed from one cell to any of its neighboring cells belonging to the same BSS.� efficiency ot the execution phase (old to new TCH channel change) of the outgoing handovers performed from one cell to any of its neighboring cells belonging to the same BSS.� distribution of outgoing intra BSC intercell HO failures per type of problem (radio drop, radio - Reversion Old Channel, BSS).

�The Outgoing Inter BSC intercell section includes indicators corresponding to the efficiency of outgoing intercell external handovers relating to a cell (serving):

� efficiency ot the preparation phase (target TCH allocation) of the outgoing handovers performed from one cell to any of its neighboring cells not belonging to the same BSS.� efficiency ot the execution phase (old to new TCH channel change) of the outgoing handovers performed from one cell to any of its neighboring cells not belonging to the same BSS.� distribution of outgoing inter BSC intercell HO failures per type of problem (radio drop, radio - Reversion Old Channel, BSS).

�The Outgoing Intra BSC + Inter BSC intercell section includes indicators corresponding to the efficiency of all outgoing intercell handovers relating to a cell (serving):

� global efficiency ot the outgoing handovers performed from one cell to any of its neighboring cells whether they belong to the same BSS or not� efficiency ot the execution phase (old to new TCH channel change) of the outgoing handovers performed from one cell to any of its neighboring cells whether they belong to the same BSS or not.� outgoing intra BSC + inter BSC intercell HO drop rate per type of problem (radio drop, radio - Reversion Old Channel, BSS).

� When the BSC is congested on the downlink, some messages are discarded. This may result for example in call establishment failures, loss of paging messages or delay in handover procedures.

A new LapD counter that indicates the time an LapD link is congested is created to analyze the cause of a degraded quality of service. This counter is implemented in type 7 and thus is only available in a detailed measurement campaign.

Counter: L1.18: TIME_LAPD_CONGDefinition: Time in seconds during which the LapD link is congested in transmission in the BSC.

B8

(See comments)


1.153

� Handover STATISTICS > Incoming handovers

3.2 Indicators classificationIncoming handovers

Failure BSS

Failure Radio

Congestion

Efficiency

Intra-BSC

Failure BSS

Failure Radio

Failure No CIC

Congestion

Efficiency

External

Efficiency

Intra-BSC & External

Incoming HO

B8

New counters and indicators for:

Incoming external HO 3G - > 2G

Incoming external HO 2G - > 2G only

New B8

(See comments)

�The Incoming Intra BSC intercell section includes indicators corresponding to the efficiency of incoming intercell internal handovers relating to a cell (target):

�efficiency ot the execution phase (old to new TCH channel change) of the incoming handovers performed to one cell from any of its neighboring cells belonging to the same BSS.� distribution of incoming intra BSC intercell HO failures per type of problem (congestion, radio, BSS).

�The Incoming Inter BSC intercell section includes indicators corresponding to the efficiency of incoming intercell external handovers relating to a cell (target):

� efficiency ot the preparation phase (target TCH allocation) of the incoming handovers performed to one cell from any of its neighboring cells not belonging to the same BSS.� distribution of incoming inter BSC intercell HO failures per type of problem (RTCH congestion, TTCH (CIC) congestion, radio, BSS)

� Using new counters introduced in B8 for 3G to 2G Incoming External Handovers,MC922a: NB_INC_EXT_3G_2G_HO_REQ (REQUESTS)MC922b: NB_INC_EXT_3G_2G_HO_SUCC (SUCCESS)MC922c: NB_INC_EXT_3G_2G_HO_EXEC_FAIL_MS_ACC (FAILURES)MC922d: NB_INC_EXT_3G_2G_HO_ATPT (ATTEMPTS)

� Creation of 4 new stored indicators based on the 4 new counters: HOIMRQUN= MC922a HOIMSUUN = MC922b HOIMFLRRUN = MC922c HOIMCAUN = MC922d

As existing PM counters related to incoming handovers keep a global view, so consider handovers from 2G cells as well as handovers from 3G cells. The pure 2G-2G results can then be obtained by comparing them with the new introduced counters:

�Creation of 4 new stored indicators for incoming external handover 2G -2G only: HOIMRQGN = MC820 - MC922a (REQUESTS) HOIMSUGN = MC642 - MC922b (SUCCESS)HOIMFLGN = MC643 - MC922c (FAILURES) HOIMCAGN = MC821 - MC922d (ATTEMPTS)

� And New calculated indicators are defined: 3G-2G HO Success rate: HOIMSUUR = MC922b / MC922a2G-2G HO Success rate: HOIMSUGR = (MC642-MC922b) / (MC820-MC922a)preparation and execution 3G-2G HO failure rate HOIMFLUR = 1 -(MC922b/MC922a)preparation and execution 2G-2G HO failure rate HOIMFLGR = 1 -((MC642-MC922b) / (MC820-MC922a))

B8


1.154

� Handover STATISTICS > Intracell handovers

3.2 Indicators classificationIntra-cell handovers

CDR Radio CDR BSS


Failure BSS

Call Drop Rate

Congestion

Efficiency

Intracell HO

�The Intracell section includes indicators corresponding to the efficiency of intracell handovers performed within a cell: �efficiency ot the execution phase (old to new TCH channel change) of the intracell handovers performed within a cell.� distribution of intracell HO failures per type of problem (congestion, radio drop, radio - Reversion Old Channel, BSS).


1.155

� Handover STATISTICS > Handover statistics per couple of cell

3.2 Indicators classificationHandover statistics per couple of cells

HO Success Distribution

Success Rate

Efficiency


HO statistics

per Couple of Cell

�The Indicators with counters type 180 section includes indicators corresponding to the efficiency of incoming internal+externalintercell SDCCH+TCH handovers performed between two cells (serving/target):

� global efficiency of the incoming intercell handovers performed between two cells (serving/target).�efficiency ot the preparation phase (old to new TCH channel change) of the incoming intercell handovers performed between two cells (serving/target).� efficiency ot the execution phase (old to new TCH channel change) of the incoming intercell handovers performed between two cells (serving/target).� distribution per couple of (serving/target) cells of the incoming intercell handovers performed to a cell from any of its neighboring cells whether they belong to the same BSS or not.


1.157

4 Handover indicatorsSession presentation

� Objective: to be able to explain what are the main Handover counters and indicators provided by the Alcatel BSS in order to monitor the quality of handovers

� Program:

4.1 Intra-cell handover indicators per cell

4.2 Internal handover indicators per cell

4.3 External handover indicators per cell

4.4 Handover indicators per couple of cells




4.1 Intra-cell handover indicators per cell


1.159

4.1 Intra-cell handover indicators per cell Handover types

HO FAIL. CASES > HO Reminder

� Intra-Cell: Handover between two TCHs of the same cell

� Internal

� between two cells of the same BSC

� also called intra BSC

� and not using the forced external handover mode

� External

� between two cells of different BSCs

� also called inter BSC

� or between two cells of the same BSC when using the forced external handover mode

TCH/(SDCCH) Handover

� Synchronous

� between 2 cells

� sharing the same clocks

� collocated

� usually 2 sectors of the same BTS

� tunable at OMC-R level

� Asynchronous

� not synchronous for any reason

� no dedicated monitoring for synchronous/asynchronous HO

� Incoming

� as considering the target cell

� Outgoing

� as considering the serving cell


1.160

4.1 Intra-cell handover indicators per cell Intracell HO - success

HO FAIL. CASES > intracell HO > successful case

MS BTS BSC MSC

MEAS REPORT-----------------------------> MEASUREMENT RESULT

--------------------------------------------------------------> MC870PHYSICAL CONTEXT REQUEST (old channel)<--------------------------------------------------------------PHYSICAL CONTEXT CONFIRM (old channel)-------------------------------------------------------------->

CHANNEL ACTIVATION (new channel)<--------------------------------------------------------------

CHANNEL ACTIVATION ACK (new channel)-------------------------------------------------------------->

ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel) MC871

<----------------------------- <-------------------------------------------------------------- start T3107SABM

-----------------------------> ESTABLISH INDICATION (new channel)UA -------------------------------------------------------------->

<-----------------------------ASSIGNMENT CMP ASSIGNMENT COMPLET(new channel)-----------------------------> --------------------------------------------------------------> stop T3107

MC662HANDOVER

PERFORMED------------------->

RF CHANNEL RELEASE (old channel)<--------------------------------------------------------------

RF CHANNEL RELEASE ACK (old channel)-------------------------------------------------------------->

� Both SDCCH and TCH are counted together.

� The T3107 timer is also used as the guard timer of the channel change procedure during an intra cell handover. The Default valuefor T3107 is 14 seconds.


1.161

4.1 Intra-cell handover indicators per cell Intracell HO - failures

HO FAIL. CASES > intracell HO failures

� Handover Preparation:

� congestion

� BSS problem (no specific counter)

� Handover Execution:

� reversion to old channel

� drop radio



1.162

HO FAIL. CASES > intracell HO failure: congestionMC561TCH+MC101SDCCH

4.1 Intra-cell handover indicators per cell Intracell HO - congestion

MS Serving BTS Serving BSC MSC


--------------------------------------------------------------> MC870No free TCH

MC561

� From B7, MC561 replaces MC61of B6.

� As the counting of the Abis-TCH congestion case is in restriction in B8:

� MC61(B6) = MC561(B7)


1.163

4.1 Intra-cell handover indicators per cell Intracell HO - radio failure ROC

HO FAIL. CASES > intracell HO failure: reversionold channel

Serving ServingMS BTS BSC MSC

MC871ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel)<----------------------------- <----------------------------------------------------------------- start T3107 (= T10)start T200

SABM (new channel)-----------------------------> ESTABLISH INDICATION (new channel)

----------------------------------------------------------------->UA (new channel)

X- - - - - --------------------SABM (new channel)

----------------------------->UA (new channel)

X- - - - - --------------------

SABM (old channel)-----------------------------> ESTABLISH INDICATION (old channel)

UA (old channel) -----------------------------------------------------------------><-----------------------------ASSIGNMENT FAIL ASSIGNMENT FAILURE-----------------------------> -----------------------------------------------------------------> stop T3107

MC667PHYSICAL CONTEXT REQUEST (new channel)

<-----------------------------------------------------------------PHYSICAL CONTEXT CONFIRM (new channel)

----------------------------------------------------------------->RF CHANNEL RELEASE (new channel)

<-----------------------------------------------------------------RF CHANNEL RELEASE ACK (new channel)

----------------------------------------------------------------->


1.164

HO FAIL. CASES > intracell HO failure: radio dropMC663=C63TCH+C103SDCCH


MC871ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel)<----------------------------- <----------------------------------------------------------------- start T3107 (= T10)

MC663Release of old and new channels T3107 expiry

4.1 Intra-cell handover indicators per cell Intracell HO - radio failure drop


1.165

HO FAIL. CASES > intracell HO failure: BSS drop

� no specific counter


MC871ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel)<----------------------------- <----------------------------------------------------------------- start T3107 (= T10)

--------------------------------------- >CLEAR REQUEST

O&M interventionRadio interface failure

4.1 Intra-cell handover indicators per cell Intracell HO - BSS problem

� Intra cell HO failures due to BSS problems are deduced from other counters.


1.166

HO FAIL. CASES > intracell HO counters

4.1 Intra-cell handover indicators per cell Intracell HO - counters

Request MC870

Congestion MC561+MC101

BSS Pb MC870-MC871-(MC561+MC101)

Attempt MC871

Reversion old channel MC667

Drop radio MC663

BSS Pb MC871-MC662-MC667-MC663

Success MC662

Preparation

Execution

INTRACELL Handover

REQUEST

CONGESTION

ATTEMPT

REVERSION OLD CHANNEL

DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure




4.2 Internal handover indicators per cell


1.168

HO FAIL. CASES > internal HO > success case

4.2 Internal handover indicators per cell Internal HO - success

The same inter-cellhandover procedure leads to an incrementation of two sets of counters:

incoming HO counters for the target cell: MC830, MC831, MC652, etc.

outgoing HO counters for the serving cell: MC655A, MC660, MC656, etc.

In HO_PERFORMED MESSAGE

� Target cell (CI,LAC)

� "cause" of HO

MS serving cell target cell BSC MSC

MEAS REP

-----------------------> MEASUREMENT RESULT

------------------------------------------------------------------------> MC830, MC655A

CHANNEL ACTIVATION

<----------------------------------

CHAN ACTIV ACK

---------------------------------->

HO CMD HANDOVER COMMAND

<----------------------- <------------------------------------------------------------------------ start T3103

MC831, MC660

start T3124

HANDOVER ACCESS

------------------------------------------------------------->

-------------------------------------------------------------> HO DETECTION

PHYSICAL INFORMATION ---------------------------------->

<------------------------------------------------------------- start T3105

stop T3124

start T200

------------------------ SABM ---------------------------> stop T3105

<-------------------------- UA ----------------------------- ESTABLISH INDICATION

stop T200 ---------------------------------->

HANDOVER COMPLETE HO CMP stop T3103

-------------------------------------------------------------> ----------------------------------> HO PERFORMED

------------------------>

Release of old TCH MC652, MC656



1.169

HO FAIL. CASES > Incoming internal HO failures:

Handover procedure from the target cell point of view


� congestion: no RTCH available in the target cell

does not concern the outgoing side (serving cell point of view)



� radio problem: the MS fails to access the new channel

the reversion/drop discrimination concerns only the serving cell


4.2 Internal handover indicators per cell Incoming internal HO - failures


1.170

HO FAIL. CASES > Incoming internal HO fail: congestionMC551TCH+MC91SDCCH

4.2 Internal handover indicators per cell Incoming internal HO - congestion

MS Serving Cell Serving BSC MSC


--------------------------------------------------------------> MC830No free TCH

MC551MC91

If no free SDCCH

� From B7, MC551 replaces MC51of B6.


� MC51(B6) = MC551(B7)


1.171

HO FAIL. CASES > Incoming internal HO fail: MS access problem

4.2 Internal handover indicators per cell Incoming internal HO - radio failure


MEAS REP


------------------------------------------------------------------------>

CHANNEL ACTIVATION

<----------------------------------

CHANNEL ACTIV ACK

---------------------------------->


<----------------------- <------------------------------------------------------------------------ start T3103

M C660

SABM

-----------x T3103 expiry

M C653

MS Serving cell Target Cell BSC


<----------------------- <------------------------------------------------------------------------ start T3103

HANDOVER ACCESS MC660

------------------------------------------------------------->

-------------------------------------------------------------> HO DETECTION


<------------------------------------------------------------- start T3105

SABM

-------------------------------------------------------------> ESTABLISH INDICATION

UA ---------------------------------->

<------------------------------------------------------------- stop T3105

HANDOVER COMPLETE

----------------------------------------------------- - - - -X

SABM

-----------------------> ESTABLISH INDICATION

UA ------------------------------------------------------------------------>

<-----------------------

HO FAILURE HANDOVER FAILURE

-----------------------> ------------------------------------------------------------------------> MC653

Release of new channel

� All incoming internal HO failures due to radio problems are counted in the same counter MC653.

� Both radio failures with Reversion Old Channel and radio drop are counted together.


1.172

HO FAIL. CASES > Incoming internal HO counters

4.2 Internal handover indicators per cell Incoming internal HO - counters

Request MC830



Attempt MC831

Radio (MS access problem) MC653

BSS Pb MC831-MC652-MC653

Success MC652

Execution

Preparation

INCOMING INTERNAL Handover

REQUEST

CONGESTION

ATTEMPT

MS ACCESS PB

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure


1.173

4.2 Internal handover indicators per cell Incoming internal HO - indicators

SUCCESS

HO FAIL. CASES > Incoming internal HO indicators


� Handover Statistics INDICATORS > Incoming handover > Incoming Intra BSC

� HOIBEFR: efficiency of the incoming internal HO execution

� HOIBCGR: rate of incoming internal HO failures due to congestion

� HOIBPFR: rate of incoming internal HO failures due to BSS during the preparation phase

� HOIBFLRR: rate of incoming internal HO failures due to radio problems

� HOIBFLBR: rate of incoming internal HO failures due to BSS during the execution phase


1.174

HO FAIL. CASES > Outgoing internal HO failures

Handover procedure from the serving cell point of view


� congestion on the target cell (no specific counter on the serving cell)



� radio problem: the MS reverts to the old channel

� radio problem: the MS drops


4.2 Internal handover indicators per cell Outgoing internal HO - failures


1.175

HO FAIL. CASES > Outgoing internal HO fail: reversionold channel

4.2 Internal handover indicators per cell Outgoing internal HO - radio failure ROC



<----------------------- <------------------------------------------------------------------------ start T3103

HANDOVER ACCESS MC660

------------------------------------------------------------->

-------------------------------------------------------------> HO DETECTION


<------------------------------------------------------------- start T3105

SABM


UA ---------------------------------->

<------------------------------------------------------------- stop T3105

HANDOVER COMPLETE

----------------------------------------------------- - - - -X

SABM


UA ------------------------------------------------------------------------>

<-----------------------


-----------------------> ------------------------------------------------------------------------> MC657



1.176

HO FAIL. CASES > Outgoing internal HO fail: drop

� clear_request: ask the MSC to release the connection

� In case of call drop due to HO, the cause is "radio interface message failure" (for Alcatel)


MEAS REP


------------------------------------------------------------------------> MC655A

CHANNEL ACTIVATION

<----------------------------------

CHAN ACTIV ACK

---------------------------------->


<----------------------- <------------------------------------------------------------------------ start T3103

MC660

SABM

----------x

T3103 expiry

MC658

Clear_request

------------------------>

Clear_command

Release of old and new TCH <------------------------

4.2 Internal handover indicators per cell Outgoing internal HO - radio failure drop


1.177

HO FAIL. CASES > Outgoing internal HO counters

4.2 Internal handover indicators per cell Outgoing internal HO - counters

Preparation Request MC655A

Any preparation failure MC655A-MC660

Attempt MC660


Drop radio MC658


Success MC656

Execution

OUTGOING INTERNAL Handover

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure


1.178

4.2 Internal handover indicators per cell Outgoing internal HO - indicators

SUCCESS

HO FAIL. CASES > Outgoing internal HO indicators


� Handover Statistics INDICATORS > Outgoing handover > Outgoing Intra BSC

� HOOBRQR: efficiency of the outgoing internal HO preparation.

� HOOBEFR: efficiency of the outgoing internal HO execution.

� HOOBOCR: rate of outgoing internal HO failures due to radio problems with Reversion Old Channel.

� HOOBCDRR: rate of outgoing internal HO failures due to radio problems with drop.

� HOOBCDR: rate of incoming internal HO failures with drop (radio + BSS).


1.179

With K1205, find in the PAIB29.REC file:

1) One case of intra-cell failure with reversion

2) One case of Internal handover success

� Identify the target cell

� Identify the serving cell (in CR for call establishment)

3) One case of Internal handover failure with reversion

4) One case of Internal handover failure without reversion

4.2 Internal handover indicators per cell Intra-cell HO / Internal HO - exercise

Time allowed:

15 minutes




4.3 External handover indicators per cell


1.181

4.3 External handover indicators per cell External HO - success

HO FAIL. CASES > External HO > successful case

B8

MS serving_cell BSC MSC BSC target_cell MS- MEAS_REPORT ->

------- MEAS_RESULT -------->MC645A ------ HO_REQUIRED ---------->

----------CR (HO_REQUEST) -----> MC820<--------- CC ------------------------ ---- CHANNEL_ACTIVATION ------>

<- CHANNEL_ACT_ACK-------------<----- HO_REQUEST_ACK -------- Start T9113

(HO_COMMAND) MC821<------------------------- HO_COMMAND ------------------------------------------------------ <---- HO_ACCESS -----

MC650 Start T8 <---- HO_ACCESS -----<------ HO_DETECTION--------------

<-- HO_DETECTION -------------- --- PHYSICAL_INFO -->

<--- SABM ---------------<----- ESTABLISH_INDICATION ---- ----- UA -------------->

<----------- HO_COMPLETE ----------------------------------------<--- HO_COMPLETE --------------- Stop T9113

<---- CLEAR_COMMAND ------ MC642MC646 Cause : HO_SUCCESSFUL

Release of TCH Stop T8

MC462A

MC462B

MC462C

MC463A

MC463B

MC463C

(See comments)


� From B7, MC645A replaces MC645 of B6.

� MC645a is only counting HANDOVER REQUIRED messages that are linked to a handover trial and not those that are linked to the update of the candidate cell list for handover / directed retry. This is leading to a more accurate computation of the External outgoing HO success rate.

� B7.2: Only Outgoing inter PLMN HO is allowed but no counters.

� B8: 6 new counters provide information for "Inter-PLMN HO" (Incoming and Outgoing)

� MC462a (equivalent of MC645A for intra PLMN external HO)Number of inter-PLMN TCH outgoing handovers or directed retry requests: HANDOVER REQUIRED sent to the MSC for an external TCH HO or an external DR triggered towards a cell belonging to a PLMN different from the PLMN of the serving cell.

� MC462b (equivalent of MC650 for intra PLMN external HO)Number of inter-PLMN TCH outgoing handovers or directed retry attempts: HANDOVER COMMAND sent to the MS on Abis for an external TCH HO or an external DR triggered towards a cell belonging to a PLMN different from the PLMN of the serving cell.

� MC462c (equivalent of MC646 for intra PLMN external HO)Number of inter-PLMN TCH outgoing handovers or directed retry successes: CLEAR COMMAND with Cause "Handover successful" received from the MSC for an external TCH HO or an external DR triggered towards a cell belonging to a PLMN different from the PLMN of the serving cell.

� MC463a (equivalent of MC820 for intra PLMN external HO)Number of inter-PLMN TCH incoming handovers or directed retry requests: HANDOVER REQUEST received from the MSC for an external TCH HO or an external DR triggered towards the target cell from a serving cell belonging to a PLMN different from the PLMN of the target cell.

� MC463b (equivalent of MC821 for intra PLMN external HO)Number of inter-PLMN TCH incoming handovers or directed retry attempts: HANDOVER REQUEST ACK sent by the target BSC containing the HANDOVER COMMAND for an external TCH HO or an external DR triggered towards the target cell from a serving cell belonging to a PLMN different from the PLMN of the target cell.

� MC463c (equivalent of MC642 for intra PLMN external HO)Number of inter-PLMN TCH incoming handovers or directed retry successes: HANDOVER COMPLETE received from the MS on Abis for an external TCH HO or an external DR triggered towards the target cell from a serving cell belonging to a PLMN different from the PLMN of the target cell.

� Note than all other (previous) counters related to HO continue to be based on Intra PLMN only.


1.182

4.3 External handover indicators per cell External HO - failures

HO FAIL. CASES > Incoming external HO failures

Handover procedure from the target cell point of view


� congestion: no RTCH available in the target cell OR no TTCH available

on the A interface








1.183

4.3 External handover indicators per cell Incoming external HO - RTCH congestion

HO FAIL. CASES > Incoming external HO fail: Air/Abis cong.MC541ATCH+MC81SDCCH


------- MEAS_RESULT -------->MC645A ------ HO_REQUIRED ------->

----------CR (HO_REQUEST) -----> MC820

<----- HO_FAILURE --------------- MC541A( <-HO_REQUIRED_REJECT-) Cause: no radio resource available

� From B7, MC541A replaces MC41A of B6.


� MC41A(B6) = MC541A(B7)


1.184

4.3 External handover indicators per cell Incoming external HO - TTCH congestion

HO FAIL. CASES > Incoming external HO fail: A int. cong.MC41B


------- MEAS_RESULT -------->MC645A ------ HO_REQUIRED ------->

----------CR (HO_REQUEST) -----> MC820

<----- HO_FAILURE --------------- MC41BCause: terrestrial circuit already allocatedRequested terrestrial resource unaivalableBSS not equiopoed

( <-HO_REQUIRED_REJECT-)


1.185

HO FAIL. CASES > Incoming external HO fail: MS accessproblem

4.3 External handover indicators per cell Incoming external HO - radio failure


------- MEAS_RESULT -------->MC645A ---- HO_REQUIRED ------->

----------CR (HO_REQUEST) -------------------> MC820<-------- CC --------------------------------------- - CHANNEL_ACT ---------->

<--- CHA_ACT_ACK --------Start T9113

<----- HO_REQUEST_ACK----------------------- Start T9113<-------------------------- HO_COMMAND ------------------------------------------------ HO-COMMAND) included° MC821

Start T8 X --- HO_ACCESS -----X ---- HO_ACCESS -----

----- SABM --- X----- SABM --- X

----- SABM --- X T9113 expiryMC643

Release of connection



----------CR (HO_REQUEST) -------------------> MC820<-------- CC --------------------------------------- - CHANNEL_ACT ---------->

<--- CHA_ACT_ACK --------<----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included MC821

<-------------------------- HO_COMMAND ------------------------------------------------Start T8 X --- HO_ACCESS -----

X ---- HO_ACCESS ---------- SABM --------><--- UA ------------- -- ESTABLISH_INDICATION->

----- HO_FAILURE (reversion to old channel) ------------------------------------------>----- CLEAR_COMMAND ----------------------> MC643Radio interface fail : Reversion to old channel


� All incoming external HO failures due to radio problems are counted in the same counter MC643.

� Both radio failures with Reversion Old Channel and radio drop are counted together.


1.186

HO FAIL. CASES > Incoming external HO counters

4.3 External handover indicators per cell Incoming external HO - counters

Request MC820



Attempt MC821

Radio (MS access problem) MC643

BSS Pb MC821-MC642-MC643

Success MC642

Execution

Preparation

INCOMING EXTERNAL Handover

REQUEST

CONGESTION

ATTEMPT

MS ACCESS PB

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

ATTEMPT SUCCESS

REQUEST

RATIO

Inter PLMN HO Intra PLMN HO

B8

New B8


1.187

4.3 External handover indicators per cell Incoming external HO - indicators

ATTEMPT

BSS PB

SUCCESS

HO FAIL. CASES > Incoming external HO indicators

B8 (See comments)


� Handover Statistics INDICATORS > Incoming handover > Incoming Inter BSC

� HOIMEFR: efficiency of the incoming external HO execution.

� HOIMCGR: rate of incoming external HO failures due to radio congestion (Air or Abis TCH).

� HOIMAMR: rate of incoming external HO failures due to CIC congestion (A TCH).

� HOIMPFR: rate of incoming external HO failures due to BSS during the preparation phase.

� HOIMFLRR: rate of incoming external HO failures due to radio problems.

� HOIMFLBR: rate of incoming external HO failures due to BSS during the execution phase.

� B8: Inter PLMN Incoming External HO Indicators

� An indicator is created for each new counter.

� REQUESTS

� ATTEMPTS

� SUCCESS

� In addition, new indicators show:

� the success rate of incoming inter-PLMN HOs,

� the ratio of incoming inter-PLMN HO to incoming intra-PLMN and inter-PLMN HO,


1.188

4.3 External handover indicators per cell Outgoing external HO - failures

HO FAIL. CASES > Outgoing external HO failures

Handover procedure from the serving cell point of view









1.189

4.3 External handover indicators per cell Outgoing external HO - radio failure ROC

HO FAIL. CASES > Outgoing external HO fail: reversion old channel



----------CR (HO_REQUEST) -------------------><-------- CC --------------------------------------- - CHANNEL_ACT ---------->

<--- CHA_ACT_ACK --------<----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included

<-------------------------- HO_COMMAND ------------------------------------------------Start T8 X --- HO_ACCESS -----MC650 X ---- HO_ACCESS -----

----- SABM --------><--- UA ------------- -- ESTABLISH_INDICATION->

----- HO_FAILURE (reversion to old channel) ------------------------------------------>MC647 ----- CLEAR_COMMAND ---------------------->

Radio interface fail : Reversion to old channelRelease of connection


1.190

4.3 External handover indicators per cell Outgoing external HO - radio failure drop

HO FAIL. CASES > Outgoing external HO fail: drop



----------CR (HO_REQUEST) -------------------><-------- CC --------------------------------------- - CHANNEL_ACT ---------->

<--- CHA_ACT_ACK --------<----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included

<-------------------------- HO_COMMAND ------------------------------------------------Start T8 X --- HO_ACCESS -----MC650 X ---- HO_ACCESS -----

----- SABM --- X----- SABM --- X

----- SABM --- X

T8 expiry ----- CLEAR_REQUEST ->MC648 Radio interface message fail



1.191

HO FAIL. CASES > Outgoing external HO counters

4.3 External handover indicators per cell Outgoing external HO - counters

Preparation Request MC645A

Any preparation failure MC645A-MC650

Attempt MC650


Drop radio MC648


Success MC646

Execution

OUTGOING EXTERNAL Handover

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

ATTEMPT SUCCESS

REQUEST

RATIO

Inter PLMN HO Intra PLMN HO

B8

New B8


1.192

4.3 External handover indicators per cell Outgoing external HO - indicators

ATTEMPT

SUCCESS

HO FAIL. CASES > Outgoing external HO indicators

B8 (See comments)


� Handover Statistics INDICATORS > Outgoing handover > Outgoing Inter BSC

� HOOMRQR: efficiency of the outgoing external HO preparation.

� HOOMEFR: efficiency of the outgoing external HO execution.

� HOOMOCR: rate of outgoing external HO failures due to radio problems with Reversion Old Channel.

� HOOMCDRR: rate of outgoing external HO failures due to radio problems with drop.

� HOOMCDR: rate of incoming external HO failures with drop (radio + BSS).

� B8: Inter PLMN Outgoing External HO Indicators

� An indicator is created for each new counter.

� REQUESTS

� ATTEMPTS

� SUCCESS

� In addition, new indicators show:

� the success rate of outgoing inter-PLMN HOs,

� the ratio of outgoing inter-PLMN HO to outgoing intra-PLMN and inter-PLMN HO.


1.193

In PAIB29.REC, extract (if available):

� 1 incoming external HO success

� 1 outgoing external HO success

� 1 incoming external HO failure

� 1 outgoing external HO failure

4.3 External handover indicators per cell External HO - exercise

Time allowed:

15 minutes




4.4 Handover indicators per couple of cells


1.195

4.4 Handover indicators per couple of cells Type 180 counters

� Some handover indicators available per couple of (serving, target) cells:

� permanently for all adjacencies through PM type 180 counters 3 counters for each (Serving,Target)

adjacency: C400(S,T): Incoming handovers requested to cell

T from cell S

C401(S,T): Incoming handovers attempted to cell

T from cell S

C402(S,T): Incoming handovers successfully

performed to cell T from cell S

both internal and external inter cell

handovers are counted

both SDCCH and TCH handovers

are counted

a

e

d

c

b

f

C40i(f,d)

C40i(a,b)C40i(c,b)

C40i(c,d)

� According to the definition of C40i counters:

� ∑ C400(Sn,T) = MC820(T) + MC830(T)

� ∑ C401(Sn,T) = MC821(T) +MC831(T)

� ∑ C402(Sn,T) = MC642(T) + MC652(T)

� where

� Sn are the serving cells considering the incoming adjacencies to cell T.

� MC820(T), MC821(T), MC642(T) are the counters relating to the incoming external handovers requested, attempted and successfully performed to cell T.

� MC830(T), MC831(T), MC646(T) are the counters relating to the incoming internal handovers requested, attempted and successfully performed to cell T.

n

n

n


1.196

4.4 Handover indicators per couple of cells Type 180 indicators

The following indicators can be computed from PM Type 180 counters in order to

� Detect the most important neighboring cells as per their traffic

� Distribution of incoming handovers performed to cell T from serving cells

Sn

= C402(Sx,T) / ∑ C402(Sn,T)

� Ease the diagnosis of the bad handover performance of a cell

� Global efficiency of incoming handovers to cell T from cell S

HOOASUR = C402(S,T) / C400(S,T)

� Efficiency of the incoming handover preparation to cell T from cell S

HOOACAR = C401(S,T) / C400(S,T)

� Efficiency of the incoming handover execution to cell T from cell S

HOOAEFR = C402(S,T) / C401(S,T)

n


� Handover Statistics > HO Statistics per couple of cells > Indicators with counter type 180

� These indicators can also be to check if a recently handover relationship is generating handover as expected.

� They will also allow to identify the handover relationships which should be deleted since no (or very few) handover is observed.


1.197

counters for each (Serving,Target x) adjacency: C720(S,Tx): Outgoing handovers attempted from

cell S to cell TxC721(S,Tx): Outgoing handovers successfully

performed from cell S to cell TxC722(S,Tx): Outgoing handovers failed from cell

S to cell Tx with Reversion Old ChannelC723(S,Tx): Outgoing handovers failed from cell

S to cell Tx with drop

these type 26 counters are available for several cells at the same time (40 cells)


� Some handover indicators are available per couple of (serving, target) cells:

� on demand for all outgoing adjacencies of a serving cell through PM type 26

Target a

Te

Serving

Tc

Tb

Tf

C72i(S,Te)

C72i(S,Tc)

B8

Modified in B8

� Other counters are provided:

� C724(S,Tx): Outgoing handovers attempted from S to Tx for an emergency cause.

� C725(S,Tx): Outgoing handovers attempted from S to Tx for a better cell cause.

� C727(S,Tx): Outgoing handovers attempted from S to Tx for a traffic cause.

� C728(S,Tx): Outgoing handovers attempted from S to Tx for a forced directed retry cause.

� Previously the set of Type 26 counters could be retrieved for only one cell per BSS at once.

� 40 cells at the same time in B8.


1.198


The following indicators can be computed from PM Type 26 counters in order to:

� ease the diagnosis of the bad outgoing handover performance of acell � Efficiency of the outgoing handover execution from cell S to cell Tx

HOOXSUR = C721(S,Tx) / C720(S,Tx)

� Rate of outgoing ho execution failures due to radio problems from S to Txwith drop

HOOXCDRR = C723(S,Tx) / C720(S,Tx)

� Rate of outgoing ho execution failures due to radio problems from S to Txwith Reversion Old Channel

HOOXOCR = C722(S,Tx) / C720(S,Tx)

� Rate of outgoing ho execution failures due to BSS problems from S to Tx

HOOXCDBR = [C720(S,Tx)-C721(S,Tx)-C722(S,Tx)-C723(S,Tx)] / C720(S,Tx)

these type 26 counters are available for several cells at once (40 cells)

B8

Modified in B8


� Handover Statistics > HO Statistics per couple of cells > Indicators with counter type 26.

� In B8, these type 26 counters are available for several cells at once (40 cells).


1.199

counters for each (Serving,Target x)

adjacency:

C730(Sx,T): Incoming handovers

attempted to cell T from cell Sx

C731(Sx,T): Incoming handovers

successfully performed to cell T from

cell Sx

C733(S,Tx): Incoming handovers failed

due to MS radio access problems to

cell T from cell Sx


� Some handover indicators are available per couple of (serving, target) cells:

� on demand for all incoming adjacencies of a target cell through PM type 27

Serving a

Se

Target

Sc

Sb

Sf

C73i(Se,T)

C73i(Sc,T)

� Other counters are provided:

� C734(Sx,T): Incoming handovers attempted from Sx to T for an emergency cause.

� C735(Sx,T): Incoming handovers attempted from Sx to T for a better cell cause.

� C737(Sx,T): Incoming handovers attempted from Sx to T for a traffic cause.

� C738(Sx,T): Incoming handovers attempted from Sx to T for a forced directed retry cause.

� The set of Type 27 counters can be retrieved for only one cell per BSS at once.


1.200


The following indicators can be computed from PM Type 27 counters in order to

� Ease the diagnosis of the bad incoming handover performance of a cell

� Efficiency of the incoming handover execution to cell T from cell Sx

HOIXSUR = C731(Sx,T) / C730(Sx,T)

� Rate of incoming ho execution failures due to MS radio access problems to cell T from cell Sx

HOIXCDRR = C733(Sx,T) / C730(Sx,T)

� Rate of incoming ho execution failures due to BSS problems to cell T from cell Sx

HOIXCDBR= [C730(Sx,T)-C731(Sx,T)-C733(Sx,T)] / C730(Sx,T)


� Handover Statistics > HO Statistics per couple of cells > Indicators with counter type 27


1.202

5 Directed retry indicatorsSession presentation

� Objective: to be able to describe the counters and indicators used for monitoring the efficiency of the directed retry feature

� Program:

5.1 Internal directed retry indicators

5.2 External directed retry indicators




5.1 Internal directed retry indicators


1.204

5.1 Internal directed retry indicators Queuing on TCH assignment

When there is no TCH available in a cell for TCH normal assignment:

� Queuing: TCH request is put in a queue, waiting for a TCH to be released in this cell

� With default BSS tuning: the call establishment fails if no TCH has been freed after T11 seconds

� but an optional mechanism can be activated

� The queuing of TCH requests is also performed for incoming external TCH handovers but not for incoming internal TCH handovers.


1.205

5.1 Internal directed retry indicators Directed retry definition

� Directed Retry (DR): When a TCH request is in queue, the BSC tries to establish the TCH connection on a neighboring cell if:

� the normal handover condition is met (Normal DR)

� specific directed retry conditions are met (Forced DR):

� the MS receives a sufficient signal level from a neighboring cell

� the number of free TCHs in this neighboring cell is sufficient


1.206

5.1 Internal directed retry indicators Directed retry types

DR FAIL. CASES > DR Reminder

DR as an SDCCH to TCH handover can be

� Internal

� between two cells of the same BSC

� also called intra BSC

� External� between two cells of different BSCs

� also called inter BSC

� Incoming� as considering the target cell

� Outgoing

� as considering the serving cell

� Synchronous

� between 2 cells

� sharing the same clocks� collocated

� usually 2 sectors of the same

BTS� tunable at OMC-R level

� Asynchronous

� not synchronous for any

reason

� no dedicated monitoring for synchronous/asynchronous

HO


1.207

DR FAIL. CASES > internal DR > success case

5.1 Internal directed retry indicators Internal DR - success

The same internal DR procedure leads to an incrementation of two sets of counters:

incoming DR counters for the target cell: MC153, MC151, etc.

outgoing DR counters for the serving cell: MC144E, MC142E, etc.

MCx counters belong to Standard Type 110 reported permanently

Cx counters belong to Detailed Type 29 reported on demand in B7.

Becomes a Standard type in B8.



< -----------------------

ASSIGNMENT

REQUESTNo free TCH

TCH request queuedQueuing allowed

Start T11 ----------------------- >

QUEUING_INDIC.MC13A

IDR condition met MC153, MC144e,

CHANNEL ACTIV. (TCH)

<---------------------------------- MC15A

CHAN ACTIV ACK

---------------------------------->


<----------------------

(SDCCH)

<------------------------------------------------------------------------ start T3103

C154, MC607

start T3124 C145A+C145C

HANDOVER ACCESS

------------------------(TCH)---------------------------->

-------------------------------------------------------------> HO DETECTION


<------------------------------------------------------------- start T3105

stop T3124

start T200

------------------------ SABM --------------------------> stop T3105

<-------------------------- UA ----------------------------- ESTABLISH INDICATION

stop T200 ---------------------------------->

HANDOVER COMPLETE HO CMP stop T3103

-------------------------------------------------------------> ----------------------------------> ASSIGNMENTCOMPLETE

------------------------>

Release of old SDCCH MC151,MC717A,MC142e

B8 (see comments)

Modified inB8

� The following DR counters are provided in Type 110

� for the target cell:

� MC13A: TCH requests for Normal Assignment that are put into the queue,

� MC153: incoming internal DR requests,

� MC15A: TCH allocations for incoming internal DR,

� MC151: incoming internal DR successes per cell,

� MC717A: incoming internal DR successes per TRX.

� for the serving cell:

� MC144E: outgoing internal DR requests,

� MC142E: outgoing internal DR successes,

� MC607: outgoing internal+external DR attempts.

� The following DR counters are provided in Type 29 (this type becomes a standard type in B8)

� for the target cell:

� C153: incoming internal DR requests,

� C154: incoming internal DR attempts,

� C151: incoming internal DR successes.


� C144A: forced outgoing internal DR requests,

� C144C: normal outgoing internal DR requests,

� C145A: forced outgoing internal DR attempts,

� C145C: normal outgoing internal DR attempts,

� C142A: forced outgoing internal DR successes,

� C142C: normal outgoing internal DR successes.

� All the counters here and in the next slides concerning directed retry and relative to type 29 can be activated for all cells of the BSC at once from B8. (Type 29 becomes a standard type in B8):

C142a, C142b, C142c, C142d, C143a, C143b, C143c, C143d, C143e, C143f, C143g, C143h, C144a, C144b, C144c, C144d, C145a, C145b, C145c, C145d, C151, C152,C153, C154, C555


1.208

DR FAIL. CASES > Incoming internal DR failures:

Directed Retry procedure from the target cell point of view

� DR Preparation:

� congestion: no RTCH available in the target cell



� DR Execution:




5.1 Internal directed retry indicators Incoming internal DR - failures


1.209

DR FAIL. CASES > Incoming internal DR fail: congestionMC555=C155

5.1 Internal directed retry indicators Incoming internal DR - congestion



< ----------------------------------------------------

ASSIGNMENT REQUEST

No free TCHIn serving cell

Queuing allowed

Start T11 --------------------------------------------------- >

QUEUING_INDIC.MC13A

IDR condition met MC153, MC144e,MC607

No free TCHIn target cell

MC555

B8 (see comments)

type 29 becomes

a standard type:

Available in PMC

� C155 is available in Type 29. (Standard type in B8)


1.210

DR FAIL. CASES > Incoming internal DR fail: MS access problem

5.1 Internal directed retry indicators Incoming internal DR - radio failure


MEAS REP


------------------------------------------------------------------------>

CHANNEL ACTIVATION

<----------------------------------

CHANNEL ACTIV ACK

---------------------------------->


<----------------------- <------------------------------------------------------------------------ start T3103

C154

SABM

-----------x T3103 expiry

C152



<----------------------- <------------------------------------------------------------------------ start T3103

HANDOVER ACCESS C154

------------------------------------------------------------->

-------------------------------------------------------------> HO DETECTION


<------------------------------------------------------------- start T3105

SABM


UA ---------------------------------->

<------------------------------------------------------------- stop T3105

HANDOVER COMPLETE

----------------------------------------------------- - - - -X

SABM


UA ------------------------------------------------------------------------>

<-----------------------


-----------------------> ------------------------------------------------------------------------> C152


B8 (see comments)

Modified inB8 Becomes a standard type

� All incoming internal DR failures due to radio problems are counted in the same counter C152.

� This counter is provided in Type 29 (this type becomes a standard type in B8).

� Both radio failures with Reversion Old SDCCH Channel and radio drop are counted together.


1.211

DR FAIL. CASES > Incoming internal DR counters

5.1 Internal directed retry indicators Incoming internal DR - counters

Request MC153, C153

Congestion MC555, C155

BSS Pb C153-C154-C155

Attempt C154

Radio (MS access problem) C152

BSS Pb C154-C151-C152

Success MC151, C151

Execution

Preparation

INCOMING INTERNAL Directed Retry

REQUEST

CONGESTION

ATTEMPT

MS ACCESS PB

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

B8 (see comments)

Modified inB8

Type 29 counters becomes a standard (PMC)

� All MCxxx counters are available in Type 110.

� All Cxxx counters are available in Type 29.

� Type 29 counters becomes a standard in B8.



� Specific indicators for densification techniques > Directed Retry > Incoming DR

�DRIBCAR: efficiency of the incoming internal DR preparation = MC15A/MC153

�DRIBCNR: rate of incoming internal DR failures due to congestion = MC155/MC153

�DRIBEFR: efficiency of the incoming internal DR execution = MC717A/MC153

� Other indicators can be computed

from Type 110 counters:

�DRIBSUR: global efficiency of incoming internal DR = MC717A/MC153 = MC151/MC153

from Type 29 counters: (Type 29 becomes a standard type in B8)

� rate of incoming internal DR preparation failures due to BSS problems = (C153-C154-C155)/C153

� rate of incoming internal DR execution failures due to BSS problems = (C154-C151-C152)/C154

� rate of incoming internal DR execution failures due to radio access problems = C152/C154


1.213

DR FAIL. CASES > Outgoing internal DR failures

Directed Retry procedure from the serving cell point of view

� DR Preparation:



� DR Execution:




5.1 Internal directed retry indicators Outgoing internal DR - failures


1.214

DR FAIL. CASES > Outgoing internal DR fail: reversionold channel

C144A, C143A: Forced DR

C144C,C143E: Normal DR

5.1 Internal directed retry indicators Outgoing internal DR - radio failure ROC



<-------SDCCH----- <------------------------------------------------------------------------ start T3103

HANDOVER ACCESS MC144E

----------------------TCH--------------------------------> C144A or C144C

-------------------------------------------------------------> HO DETECTION


<------------------------------------------------------------- start T3105

SABM


UA ---------------------------------->

<------------------------------------------------------------- stop T3105

HANDOVER COMPLETE

----------------------------------------------------- - - - -X

SABM


UA ------------------------------------------------------------------------>

<-----------------------


-----------------------> ------------------------------------------------------------------------> C143A or C143E


B8 (see comments)

� Type 29 counters becomes a standard in B8.


1.215

DR FAIL. CASES > Outgoing internal DR fail: drop

M S serv ing ce ll targe t ce ll BS C M SC

H O C M D H A N D O VER C O M M A N D

<----------------------- < ------------------------------------------------------------------------ start T 3103

M C 144E

S ABM C 144A or C 144C

----------x

T 3103 exp iry

C 143B o r C 143F

------------------------>

A SS IG N M EN TFAILU R E

“R ad io in terfacem essage fa ilu re ”

R elease o f S D C C H an d TC H

5.1 Internal directed retry indicators Outgoing internal DR - radio failure drop

C144A,C143B: Forced DR

C144C,C143F: Normal DR

(See comments)B8

� Counters C144A, C143B, C144C, C143F are type 29.

� Type 29 becomes a standard type in B8.


1.216

DR FAIL. CASES > Outgoing internal DR counters

5.1 Internal directed retry indicators Outgoing internal DR - counters

Preparation Request MC144E, C144A+C144C

Any preparation failure (C144A+C144C) - (C145A+C145C)

Attempt C145A+C145C

Reversion old channel C143A+C143E

Drop radio C143B+C143F

BSS Pb (C145A+C145C) - (C143A+C143E+C143B+C143F)

Success MC142E, C142A+C142C

Execution

OUTGOING INTERNAL Directed Retry

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

(See comments)B8

Modified in B8

Detailed Pb available in standard type

� B8: Pb details available in PMC (type 29 becoming standard)



� Specific indicators for densification techniques > Directed Retry > Outgoing DR

�DROBSUR: global efficiency of outgoing internal DR = MC142E/MC144E



� efficiency of the outgoing internal DR preparation = (C145A+C145C)/(C144A+C144C)

� efficiency of the outgoing internal DR execution = (C142A+C142C)/(C145A+C145C)

� rate of outgoing internal DR execution failures due to BSS problems = [(C145A+C145C) - (C143A+C143E+C143B+C143F)] / (C145A+C145C)

� rate of outgoing internal DR execution failures due to radio problems with reversion old channel = (C143A+C143E) / (C145A+C145C)

� rate of outgoing internal DR execution failures due to radio problems with drop = (C143B+C143F) / (C145A+C145C)

In B8, as Type 29 becomes a standard, 10 new stored indicators based on type 29 counters are defined:

� DRFOSUIN C142a NB_OUT_FORCED_IDR_SUCC

� DRFOSUEN C142b NB_OUT_FORCED_EDR_SUCC

� DROBSUIN C142c NB_OUT_NOR_IDR_SUCC

� DROMSUEN C142d NB_OUT_NOR_EDR_SUCC

� DRFORDIN C144a NB_OUT_FORCED_IDR_REQ

� DRFORDEN C144b NB_OUT_FORCED_EDR_REQ

� DROBRDIN C144c NB_OUT_NOR_IDR_REQ

� DROMRDEN C144d NB_OUT_NOR_EDR_REQ

� DROBRQIN C145c NB_OUT_NOR_IDR_ATPT

� DROMRQEN C145d NB_OUT_NOR_EDR_ATPT� Type 29 counters becomes a standard in B8.




5.2 External directed retry indicators


1.219

5.1 External directed retry indicators External DR - success

DR FAIL. CASES > External DR > successful case

MS serving_cell BSC MSC BSC target_cell MSTCH request queued <------ASSIGNT REQUEST-------

EDR condition met ------ HO_REQUIRED ---------->MC144F ----------CR (HO_REQUEST) -----> MC820

<--------- CC ------------------------ ---- CHANNEL_ACTIVATION ------><- CHANNEL_ACT_ACK-------------

<----- HO_REQUEST_ACK -------- Start T9113(HO_COMMAND) MC821

<------------------------- HO_COMMAND ------------------------------------------------------ <---- HO_ACCESS -----C145B+C145D Start T8 <---- HO_ACCESS -----

<------ HO_DETECTION--------------<-- HO_DETECTION -------------- --- PHYSICAL_INFO -->

<--- SABM ---------------<----- ESTABLISH_INDICATION ---- ----- UA -------------->

<----------- HO_COMPLETE ----------------------------------------<--- HO_COMPLETE --------------- Stop T9113

<---- CLEAR_COMMAND ------ MC642MC142F Cause : HO_SUCCESSFUL

Release of SDCCH Stop T8

The same external DR procedure leads to an incrementation of two sets of counters: incoming external HO counters for the target cell: MC820, MC821, etc.outgoing external DR counters for the serving cell: MC144F, MC142F, etc.

B8 (see comments)



� MC144F: outgoing external DR requests,

� MC142F: outgoing external DR successes.



� C144B: forced outgoing external DR requests,

� C144D: normal outgoing external DR requests,

� C145B: forced outgoing external DR attempts,

� C145D: normal outgoing external DR attempts,

� C142B: forced outgoing external DR successes,

� C142D: normal outgoing external DR successes.

� As for internal DR, external DR Counters are available permanently (Type 29 becomes a standard type in B8)

� No counter is provided for the target cell for an external DR since an incoming DR cannot always be discriminated from an incoming external HO. Therefore incoming external DRs are counted together with incoming external HOs in the related counters.


1.220

5.1 External directed retry indicators Outgoing external DR - failures

DR FAIL. CASES > Outgoing external DR failures

Directed Retry procedure from the serving cell point of view

� DR Preparation:



� DR Execution:





1.221

5.1 External directed retry indicators Outgoing external DR - radio failure ROC

DR FAIL. CASES > Outgoing external DR fail: reversionold channel

MS serving_cell BSC MSC BSC target_cell MSASSIGNT REQUEST---------------------> TCH request queued

EDR condition met ---- HO_REQUIRED ------->MC144F ----------CR (HO_REQUEST) ------------------->

<-------- CC --------------------------------------- - CHANNEL_ACT ----------><--- CHA_ACT_ACK --------

<----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included


C145B+C145D X ---- HO_ACCESS ---------- SABM --------><--- UA ------------- -- ESTABLISH_INDICATION->

----- HO_FAILURE (reversion to old channel) ------------------------------------------>C143C+C143G ----- CLEAR_COMMAND ---------------------->

Radio interface fail : Reversion to old channelRelease of connection

C145B,C143C: Forced DR

C145D,C143G: Normal DR


1.222

5.1 External directed retry indicators Outgoing external DR - radio failure drop

DR FAIL. CASES > Outgoing external DR fail: drop

MS serving_cell BSC MSC BSC target_cell MSASSIGNT REQUEST---------------------> TCH request queued

EDR condition met ---- HO_REQUIRED ------->MC144F ----------CR (HO_REQUEST) ------------------->

<-------- CC --------------------------------------- - CHANNEL_ACT ----------><--- CHA_ACT_ACK --------

<----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included


C145B+C145D X ---- HO_ACCESS ---------- SABM --- X----- SABM --- X

----- SABM --- X

T8 expiry ----- CLEAR_REQUEST ->C143D+C143H Radio interface message fail



1.223

DR FAIL. CASES > Outgoing external DR counters

5.1 External directed retry indicators Outgoing external DR - counters

Preparation Request MC144F, C144B+C144D

Any preparation failure (C144B+C144D) - (C145B+C145D)

Attempt C145B+C145D

Reversion old channel C143C+C143G

Drop radio C143D+C143H

BSS Pb (C145+C145D) - (C143C+C143G+C143D+C143H)

Success MC142F, C142B+C142D

Execution

OUTGOING EXTERNAL Directed Retry

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure



� Specific indicators for densification techniques > Directed Retry > Outgoing DR

�DROMSUR: global efficiency of outgoing external DR = MC142F/MC144F



� efficiency of the outgoing internal DR preparation = (C145B+C145D)/(C144B+C144D)

� efficiency of the outgoing internal DR execution = (C142B+C142D)/(C145B+C145D)

� rate of outgoing internal DR execution failures due to BSS problems = [(C145B+C145D) - (C143C+C143G+C143D+C143H)] / (C145B+C145D)

� rate of outgoing internal DR execution failures due to radio problems with reversion old channel = (C143C+C143G) / (C145B+C145D)

� rate of outgoing internal DR execution failures due to radio problems with drop = (C143D+C143H) / (C145B+C145D)

� Interesting indicator:

�TCQUSUDSR: rate of outgoing internal and external directed retries (forced + normal) successfully performed over all RTCH requests queued during normal assignment.


1.226

6 Radio Measurement Statistics indicatorsSession presentation

� Objective: to be able to describe the RMS indicators used for radio quality assessment of a TRX or cell and to use them in thedetection of some typical radio problems

� Program:

6.1 Radio Measurement Statistics objectives

6.2 RMS implementation in the BSS

6.3 RMS data

6.4 Call quality statistics per TRX

6.5 Radio quality statistics per TRX

6.6 C/I statistics

6.7 RMS indicators usage

6.8 Additional information




6.1 Radio Measurement Statistics objectives


1.228

6.1 Radio Measurement Statistics objectivesRMS objectives

RMS objectives

� Assess the quality of cell coverage

� Assess the radio link quality of a TRX / a cell

� Assess Carrier/Interference ratio of a TRX / a cell

� Estimate of the voice quality of a TRX / a cell

In order to:

�Optimize the neighborhood & frequency planning

� Improve the network coverage

�Detect faulty hardware components responsible for badQoS

�Help logical parameters fine tuning

� The RMS feature provides statistics on Voice Quality. VQ data are now needed since the Call Drop rate is not sufficient to have a clear picture of the QoS in a network using Slow Frequency Hopping as a densification technique.

� The RMS feature is a "plus" providing additional information to help radio engineer in their Fault detection and Network optimization tasks.


1.229

6.1 Radio Measurement Statistics objectivesRMS objectives

RMS objectives

� Provide Radio Measurement Statistics

� On all the network elements (all TRXs/cells)

� Permanently (RMS results available every day)

In order to

�Reduce the cost of Radio Network Optimization

� Today's solutions for Radio Measurements are limited and very expensive:

� drive tests: provide a mobile user with the perception of the network but cannot be done on the whole network and on an very day basis since:

� they are costly (tool+car+manpower).

� they need to be post-processed.

� they are limited to part of the network.

� they are available on the DownLink path only.

� Abis interface traces: provide a complete Uplink and Downlink radio quality assessment of a cell but cannot be done on the whole network and on an every day basis since:

� they are costly (protocol analyzer+manpower).

� they need to be post-processed.

� they are limited to a few cells at once per analyzer.




6.2 RMS implementation in the BSS


1.231

6.2 RMS implementation in the BSSRMS management

� RMS results are reported permanently (once a day) by the BSS

as new PM counters to the OMC-R

� The RMS job is defined and activated on a per BSS basis

� RMS job parameters are managed through RMS templates

� RMS templates provide means to tune RMS parameters

according to Cell Planning (cell profile, cell class)

� The cell profile can be: micro, indoor, multiband, etc.

� The cell class can be: rural, urban, rural rapid (covering express railway), etc.

� Templates parameters define the intervals or Received level, Consecutive frame erasure, Radio link counter, Path balance, C/I …for which RMS counters are provided.


1.232

6.2 RMS implementation in the BSSRMS configuration in the OMC-R

PM

RMS in binary filesTemplatesTemplates

RMS with OMC-R only

� Templates are defined on the OMC-R

� RMS results are retrieved once a day from the BSC

� Binary files can be exported for post-processing


1.233

6.2 RMS implementation in the BSSRMS configuration in RNO

RMS with OMC-R, NPA & RNO� Templates are defined on RNO

� RMS results are retrieved once a day from the BSC

� Binary files are transferred to NPA

� RMS warnings on NPA

� RMS QoS reports on RNO

� RMS reports used in RNO

� Check

� QoS follow-up

� Diagnosis

� Tuning

� The Experience matrix can be generated for network planning

� Excel export is adapted to RMS

Benefit to whole RNO

Templates

PMComputeexperience

matrix

� The cell profile can be: micro, indoor, multiband, etc.

� The cell class can be: rural, urban, rural rapid (covering express railway), etc.


1.234

6.2 RMS implementation in the BSSRMS data flow

RNO defines and sends

RMS templates to the OMC-R

The OMC-R activates an RMS campaign

in the BSS

RMS counters are transferred to

the OMC

RMS counters are stored in NPA

RMS indicators

requested by RNO

RMS QOS reportdisplayed

RNO calculates and exports the

Experience matrix to RNP

1

2

3

4

5

A9156 RNO

NPA

RNP

OMC-R

BSS

Template

1

Experience matrix

7

PM4

7

2PM

3

6

5QOS

6

QOS

� RNO is able to define the templates for the RMS jobs and helps in defining the MAFA frequencies.

� The tuning function of RNO defines a preferred RMS template depending on cell characteristics (type, class, capacity, etc.).

� RNO manages the frequencies to monitor through MAFA jobs depending on the neighborhood and the frequency bands.

� RNO is a reference for RMS templates:

� 16 templates stored in the RNO database,

� Reference values for templates available,

� Extra editor in the administration tool to modify templates:

� a given value or a reference one.

� NPA

� NPA stores RMS jobs measurements, at Cell & TRX levels (15 days).

� NPA makes some consolidations (voice quality, averages, etc.).

� NPA manages some warnings on RMS indicators (path balance).

� The Experience Matrix generated by RNO is an interference matrix computed from C/I measurements provided through RMS counters.


1.235

� In all this chapter

� System parameters (user tunable or not) will always be

written in BLUE BOLD FONT

� Indicators and counters will be typed

in ITALIC and SHADOW EFFECT FONTITALIC and SHADOW EFFECT FONT

� The light blue font highlights important points

6.2 RMS implementation in the BSSRMS data presentation




6.3 RMS data


1.237

� 3 main RMS statistics types

� Call quality statistics which qualify calls according to

coverage/interference criteria

� based on samples corresponding to measurement

results averaged over a number of SACCH multi-frames

� Radio statistics:

� UL/DL level, UL/DL qual,

� CFE

� C/I statistics on neighboring freq/MAFA freq

� last 2 statistics types based on samples corresponding

to measurement results

6.3 RMS dataRMS data presentation

Annex 1

� The first RMS Statistics type is based on calls.

� The two others are based on TRX/Cell.

� additional information� Measurement results, TRX, BS/MS max power

� MAFA = Mobile Assisted Frequency Allocation is a GSM Phase 2+ feature allowing to request a mobile to measure and report through Extended Measurement Report message a C/I value for each frequency specified in an Extended Measurement Order message.

� CFE: Consecutive Frame Erasure

� 1 SACCH multi-frame (SACCH mfr) corresponds to 4 consecutive sequences of 26 TDMA frames during which, in the uplink, a measurement report message is received by the BTS from the MS.





6.4.1 Generalities


1.240

6.4.1 GeneralitiesVoice Quality problem

Suspecting a Voice Quality problem

� Percentage of Noisy calls

� The fact that FER measurements are more reliable than RXQUAL ones to assess the VQ is even more true when using Slow Frequency Hopping. In this case RXQUAL values are not anymore correlated to Voice Quality as perceived by the end user.

� FER measurements are available for the uplink path only.

� These RMS indicators are provided on the RNO tool per TRX, per Cell:

� Number of Noisy calls suffering from problem of bad coverage on the uplink pathRMVQULVN = RMS_call_noisy_UL_bad_coverage

� Number of Noisy calls suffering from problem of interference on the uplink pathRMVQUIFN = RMS_call_noisy_UL_interference

� Number of Noisy calls suffering from problem of interference and bad coverage considered together on the uplink pathRMVQUUKN = RMS_call_noisy_UL_undefined

� Rate of Noisy calls suffering from problems of interference or/and bad coverage on the uplink pathRMVQUNOR = RMS_call_noisy_UL_rate

� Note: The 4 indicators above can be provided for Noisy calls suffering from VQ problems on the dowlink path.

� Rate of Noisy calls but with good FER measurements on the uplink pathRMVQFEGR = RMS_call_noisy_good_FER_rate

� Rate of Noisy calls and also with bad FER measurements on the uplink pathRMVQFEBR = RMS_call_noisy_bad_FER_rate

� Rate of calls with fair quality measurements but with bad FER measurements on the uplink pathRMVQFEAR = RMS_call_abnormal_bad_FER_rate

� This last indicator can be used in order to tune the RMS VQ parameters used to characterize a call as Noisy.


1.241

6.4.1 GeneralitiesCall Quality measurements

VQ_AVERAGE = 4 SACCH

AV_RXLEV_UL_VQ = (RxlevUL1+RxlevUL2+RxlevUL3+RxlevUL4) / 4

AV_RXLEV_DL_VQ = (RxlevDL1+RxlevDL2+RxlevDL3+RxlevDL4) / 4

AV_RXQUAL_UL_VQ = (RxqualUL1+RxqualUL2+RxqualUL3+RxqualUL4) / 4

AV_RXQUAL_DL_VQ = (RxqualDL1+RxqualDL2+RxqualDL3+RxqualDL4) / 4

AV_RXFER_UL_VQ = (Nb of speech frames wrongly decoded (BFI=1)

/ Total nb of speech frames of the CQS)

Average level, quality and FER of a Call Quality Sample

SACCH meas.begin end

CALL

480ms

CQS1 CQS2 CQS3 CQS4 CQS5 CQS6 CQS7 CQS8 CQS9 CQS10 CQS11 CQS12 CQS13 CQS14 CQS15 CQS16CQS375

1 measurement report⇔⇔⇔⇔

1 SACCH mfr

� CQS: Call Quality Sample

� VQ_AVERAGE = Number of consecutive SACCH measurements from which the reported Level and Quality notes (UL and DL) are averaged. The resulting averages represent the level and quality of the corresponding Call Quality Sample, i.e. the portion of the call over which level and quality have been measured.

� AV_RXLEV_xx_VQ = Average xx level measured over a Call Quality Sample (VQ_AVERAGE SACCH)

� AV_RXQUAL_xx_VQ = Average xx quality measured over a Call Quality Sample (VQ_AVERAGE SACCH)


1.242

6.4.1 GeneralitiesClassification of a CQS and Noisy Call identification

quality

Level (dBm)

7

0

-110 -47VQ_RXLEV

bad quality + good level

interfered CQS

bad quality & level

bad coverage CQS

VQ_RXQUAL

CQS

How to qualify the quality of a call? By looking at the repartition of the CQS!!:

� VQ_RXLEV = radio level threshold to classify a CQS as bad coverage CQS.

� VQ_RXQUAL = radio quality threshold to classify a CQS as bad coverage CQS.

� VQ_INTF_THRESHOLD = Ratio of bad CQS (interference or bad coverage) to classify a Call as Noisy.

� A call is classify as:

� Noisy xx Interference if Ratio of xx interfered CQS > VQ_INTF_THRESHOLD

� Noisy xx Coverage if Ratio of xx bad coverage CQS > VQ_INTF_THRESHOLD

� Noisy xx Undefined if Ratio of (xx interfered CQS + xx bad coverage CQS) > VQ_INTF_THRESHOLD





6.4.2 Call quality parameters


1.244

6.4.2 Call quality parametersRMS parameters

Call quality statistics

Parameters used to determine if a call is noisy (according to RXQUAL) and of bad voice quality (according to FER)

� VQ_AVERAGE: averaging window size on measurement results to obtain Call Quality Samples (CQSs) (0 SACCH mfr to 128 Smf)

� VQ_RXLEV: radio level threshold to specify a bad coverage CQS for noisy call statistics (-110 to -65 dBm)

� VQ_RXQUAL: radio quality threshold to specify a bad quality (RXQUAL) CQS for noisy call statistics (0 to 7)

� VQ_RXQUAL_VS_RXFER: radio quality threshold to specify a bad or a good quality CQS correlated to bad or good FER measurements for noisy call statistics (0 to 7)

� All these parameters are included in the RMS PM Type 31 result files as RMS counters:

� RMSpc = PAR_VQ_AVERAGE

� RMSpd = PAR_VQ_RXLEV

� RMSpe = PAR_VQ_RXQUAL

� RMSpf = PAR_VQ_RXQUAL_VS_RXFER

� Call Quality Sample (A CQS) will be qualified as “of bad level” if the Average RxLevel is lower than VQ_RXLEV

� A CQS will be qualified as “of bad quality” if the Average RxQuality is greater than VQ_RXQUAL

� For FER counters, VQ_RXQUAL_VS_RXFER is used instead of VQ_RXQUAL to qualify a CQS as “of bad quality” if the Average FER is also checked (compared to VQ_xx_RXFER).

� Note: For CQS, the averaging process is non-sliding.


1.245

6.4.2 Call quality parametersRMS parameters

call quality statistics

� VQ_GOOD_RXFER: Frame Erasure Rate threshold to specify a good FER CQS for noisy call statistics (0 to 20%)

� VQ_BAD_RXFER: FER threshold to specify a bad FER CQS for noisy call statistics (0 to 20%)

� VQ_INTF_THRESHOLD: Call Quality Samples threshold to characterize a call as noisy (0 to 100%)

� VQ_FER_THRESHOLD: Call Quality Samples threshold to characterize a call as “of bad or good” voice quality (0 to 100%)


� RMSpg = PAR_VQ_GOOD_RXFER

� RMSph = PAR_VQ_ BAD_RXFER

� RMSpi = PAR_VQ_INTF_THRESHOLD

� RMSpj = PAR_VQ_FER_THRESHOLD





6.4.3 Call quality counters


1.247

6.4.3 Call quality countersRMS counters (1/4)

�� VQ_NOISY_UL_INTERFERENCEVQ_NOISY_UL_INTERFERENCE

RMS10 = Number of calls suffering from interference problem on the uplink path

�� VQ_NOISY_UL_INTERFERENCEVQ_NOISY_UL_INTERFERENCE is incremented whenever a call verifies: 100*(INTERFERED_UL_SAMPLES / NUM_UL_SAMPLES) > VQ_INTF_THRESHOLD

with INTERFERED_UL_SAMPLES = nb of times where AV_RXQUAL_UL_VQ > VQ_RXQUALand AV_RXLEV_UL_VQ>VQ_RXLEV

� Call Quality Statistics counters are related only to speech channels.

Considering:AV_RXQUAL_UL_VQ: average on VQ_AVERAGE measurements of RXQUAL_UL

AV_RXLEV_UL_VQ: average on VQ_AVERAGE measurements of RXLEV_UL

NUM_UL_SAMPLES: total number of averages calculated on UL measurements during the call on the considered TRX


1.248

�� VQ_NOISY_UL_INTERFERENCEVQ_NOISY_UL_INTERFERENCE

RMS10 = Number of calls suffering from interference problem on the uplink path

�� VQ_NOISY_DL_INTERFERENCEVQ_NOISY_DL_INTERFERENCERMS11 = Number of calls suffering from interference problem on the downlink path

�� VQ_NOISY_UL_COVERAGEVQ_NOISY_UL_COVERAGERMS12 = Number of calls suffering from bad coverage problem on the uplink path

�� VQ_NOISY_DL_COVERAGEVQ_NOISY_DL_COVERAGERMS13 = Number of calls suffering from bad coverage problem on the downlink path


� RMS10 = VQ_NOISY_UL_INTERFERENCE is incremented whenever a call verifies: 100*(INTERFERED_UL_SAMPLES / NUM_UL_SAMPLES) > VQ_INTF_THRESHOLD

with INTERFERED_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL and AV_RXLEV_UL_VQ>VQ_RXLEV

consideringAV_RXQUAL_UL_VQ: average on VQ_AVERAGE measurements of RXQUAL_UL

AV_RXLEV_UL_VQ: average on VQ_AVERAGE measurements of RXLEV_UL

NUM_UL_SAMPLES: total number of averages calculated on UL measurements during the call on the considered TRX

� RMS11 = VQ_NOISY_DL_INTERFERENCE is incremented whenever a call verifies: 100*(INTERFERED_DL_SAMPLES / NUM_DL_SAMPLES) > VQ_INTF_THRESHOLD

with INTERFERED_DL_SAMPLES = nb of times when AV_RXQUAL_DL_VQ > VQ_RXQUAL and AV_RXLEV_DL_VQ>VQ_RXLEV

consideringAV_RXQUAL_DL_VQ: average on VQ_AVERAGE measurements of RXQUAL_DL

AV_RXLEV_DL_VQ: average on VQ_AVERAGE measurements of RXLEV_DL

NUM_DL_SAMPLES: total number of averages calculated on DL measurements during the call on the considered TRX

� RMS12 = VQ_NOISY_UL_COVERAGE is incremented whenever a call verifies: 100*(BAD_COVERAGE_UL_SAMPLES / NUM_UL_SAMPLES) > VQ_INTF_THRESHOLD

with BAD_COVERAGE_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL and AV_RXLEV_UL_VQ<=VQ_RXLEV

� RMS13 = VQ_NOISY_DL_COVERAGE is incremented whenever a call verifies: 100*(BAD_COVERAGE_DL_SAMPLES / NUM_DL_SAMPLES) > VQ_INTF_THRESHOLD

with BAD_COVERAGE_DL_SAMPLES = nb of times when AV_RXQUAL_DL_VQ > VQ_RXQUAL and AV_RXLEV_DL_VQ<=VQ_RXLEV


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�� VQ_NOISY_UL_UNDEFINEDVQ_NOISY_UL_UNDEFINEDRMS14 = Number of calls suffering from both problems of interference and bad coverage on the uplink path

� These calls are not counted in VQ_NOISY_UL_COVERAGE or VQ_NOISY_UL_INTERFERENCE

�� VQ_NOISY_DL_UNDEFINEDVQ_NOISY_DL_UNDEFINEDRMS15 = Number of calls suffering from both problems of interference and bad coverage on the downlink path

� These calls are not counted in VQ_NOISY_DL_COVERAGE or VQ_NOISY_DL_INTERFERENCE


� RMS14 = VQ_NOISY_UL_UNDEFINED is incremented whenever a call verifies: 100*(BAD_COVERAGE_UL_SAMPLES / NUM_UL_SAMPLES) <= VQ_INTF_THRESHOLDand 100*(INTERFERED_UL_SAMPLES / NUM_UL_SAMPLES) <= VQ_INTF_THRESHOLDand 100*(BAD_QUALITY_UL_SAMPLES / NUM_UL_SAMPLES) > VQ_INTF_THRESHOLD

with BAD_COVERAGE_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL and AV_RXLEV_UL_VQ<=VQ_RXLEV

INTERFERED_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUALand AV_RXLEV_UL_VQ > VQ_RXLEV

BAD_QUALITY_UL_SAMPLES = INTERFERED_UL_SAMPLES + BAD_COVERAGE_UL_SAMPLES= nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL

� RMS15 = VQ_NOISY_DL_UNDEFINED is incremented whenever a call verifies: 100*(BAD_COVERAGE_DL_SAMPLES / NUM_DL_SAMPLES) <= VQ_INTF_THRESHOLDand 100*(INTERFERED_DL_SAMPLES / NUM_DL_SAMPLES) <= VQ_INTF_THRESHOLDand 100*(BAD_QUALITY_DL_SAMPLES / NUM_DL_SAMPLES) > VQ_INTF_THRESHOLD

withBAD_COVERAGE_DL_SAMPLES = nb of times when AV_RXQUAL_DL_VQ > VQ_RXQUAL and AV_RXLEV_DL_VQ<=VQ_RXLEV

INTERFERED_DL_SAMPLES = nb of times when AV_RXQUAL_DL_VQ > VQ_RXQUAL and AV_RXLEV_DL_VQ > VQ_RXLEV

BAD_QUALITY_DL_SAMPLES = INTERFERED_DL_SAMPLES + BAD_COVERAGE_DL_SAMPLES= nb of times when AV_RXQUAL_DL_VQ > VQ_RXQUAL


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�� VQ_NOISY_UL_BAD_FERVQ_NOISY_UL_BAD_FER

RMS16 = Number of calls with bad quality measurements and with bad FER measurements on the uplink path

� Bad quality means bad RXQUAL whatever RXLEV is

�� VQ_NOISY_UL_GOOD_FERVQ_NOISY_UL_GOOD_FERRMS17 = Number of calls with bad quality measurements but with good FER measurements on the uplink path

�� VQ_ABNORMAL_BAD_FERVQ_ABNORMAL_BAD_FERRMS18 = Number of calls with fair quality measurements but with bad FER measurements on the uplink path


� RMS16 = VQ_NOISY_UL_BAD_FER is incremented whenever a call verifies: 100*(BAD_QUALITY_UL_SAMPLES / NUM_UL_SAMPLES) > VQ_INTF_THRESHOLDand 100*(BAD_QUAL_BAD_FER_UL_SAMPLES / BAD_QUALITY_UL_SAMPLES) > VQ_FER_THRESHOLD

withBAD_QUALITY_UL_SAMPLES = INTERFERED_UL_SAMPLES + BAD_COVERAGE_UL_SAMPLES= nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL

BAD_QUAL_BAD_FER_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL_VS_RXFER and AV_RXFER_UL_VQ > VQ_BAD_RXFER

consideringAV_RXFER_UL_VQ: average on VQ_AVERAGE measurements of FER

� RMS17 = VQ_NOISY_UL_GOOD_FER is incremented whenever a call verifies: 100*(BAD_QUALITY_UL_SAMPLES / NUM_UL_SAMPLES) > VQ_INTF_THRESHOLDand 100*(BAD_QUAL_GOOD_FER_UL_SAMPLES / BAD_QUALITY_UL_SAMPLES) > VQ_FER_THRESHOLD

with BAD_QUALITY_UL_SAMPLES = INTERFERED_UL_SAMPLES + BAD_COVERAGE_UL_SAMPLES= nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL

BAD_QUAL_GOOD_FER_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ > VQ_RXQUAL_VS_RXFER and AV_RXFER_UL_VQ <= VQ_GOOD_RXFER

� RMS18 = VQ_ABNORMAL_BAD_FER is incremented whenever a call verifies: 100*(FAIR_QUAL_BAD_FER_UL_SAMPLES / FAIR_QUALITY_UL_SAMPLES) > VQ_FER_THRESHOLD

withFAIR_QUALITY_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ < VQ_RXQUAL_VS_RXFER

FAIR_QUAL_BAD_FER_UL_SAMPLES = nb of times when AV_RXQUAL_UL_VQ<VQ_RXQUAL_VS_RXFER and AV_RXFER_UL_VQ>VQ_BAD_RXFER





6.5.1 Generalities


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6.5.1 Generalities TRX hardware problem

Suspecting a TRX hardware problem

� Average Path Balance


� Vector of the Number of Measurement Results per Path Balance bandRMPBV = RMS_PathBalance_sample

� Average Path Balance valueRMPBAN = RMS_PathBalance_avg

� A Templates modification is needed to have more details.


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6.5.1 Generalities Vector counter

� The real number of Measurement Results in which Path balance is in PATH BALANCE band j is equal to:

� S(PATH BALANCE band j) x Max / 254

� TPR_PATH_BALANCE(j) x MAX_PATH_BALANCE / 254

RMS7a=TPR_PATH_BALANCETPR_PATH_BALANCE RMS7b=MAX_PATH_BALANCEMAX_PATH_BALANCE

� The vector counter system is used to provide:

� Path balance repartition

� Radio Link counter (Consecutive Frame Erasure) repartition

� C/I repartition

� AMR FR/HR/DL/UL usage repartition

� TA repartition (improved) B8


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6.5.1 Generalities Cell coverage problem

Suspecting a cell coverage problem

� Distribution of samples per RxQual value and RxLev band

� Distribution of samples per RxLev band

� A coverage problem is observed when a significant amount of the traffic of a cell is suffering from both low level and bad quality (RxQual).

� To confirm the distribution of samples per RXLEV band, should also be considered to know the proportion of calls which are experiencing a low signal level.

� If a lot of samples of low level and bad quality are observed for only a sub-part of the TRXs (can be one only) then a BTS hardware problem or a problem on the aerials should be suspected.

� If all the TRXs are experiencing a lot of samples of low level and bad quality then a coverage problem shall be suspected.


� Matrix of Number of Measurement Results per DL RxQual value and per DL RxLev bandRMQLDSAM = RMS_DL_RxQuality_RxLevel_sample

� Vector of Percentage of Samples per DL RxLev bandRMQLDLVDV = RMS_DL_RxLevel_distrib

� Vector of Percentage of Samples per DL RxQual bandRMQLDQUDV = RMS_DL_RxQuality_distrib


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6.5.1 Generalities Matrix counter

TPR_RXQUAL_UL_RXLEV_ULTPR_RXQUAL_UL_RXLEV_UL TMR_RXQUAL_UL_RXLEV_ULTMR_RXQUAL_UL_RXLEV_UL

� This counter RMS3a=TPR_RXQUAL_UL_RXLEV_UL is a matrix

� represented on the left side

� This counter RMS3b=TMR_RXQUAL_UL_RXLEV_UL is a vector

� represented on the right side

� The real number of Measurement Results in which UL RxQual is equal to i and UL RxLev is in RXLEV band j, is equal to :

� S(RXQUAL i, RXLEV band j) x Max j / 254

� TPR_RXQUAL_UL_RXLEV_UL(i,j) x TMR_RXQUAL_UL_RXLEV_UL(j) / 254





6.5.2 Radio quality parameters


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6.5.2 Radio quality parametersRMS parameters (1/3)

Radio quality statistics

parameters used to define intervals for RXLEV, Path Balance, Radio Link Counter and Consecutive Frame Erasure statistics

� MEAS_STAT_LEV1 to MEAS_STAT_LEV9: 9 thresholds on the received radio level value defining 10 RXLEV bands

� -110 ≤ MEAS_STAT_LEV(i+1) ≤ MEAS_STAT_LEV(i) < -47 dBm

� MEAS_STAT_PATH_BAL1 to MEAS_STAT_PATH_BAL9: 9 thresholds on the radio signal propagation loss difference between UL and DL defining 10 Path Balance bands

� -110 < MEAS_STAT_PATH_BAL(i) ≤ MEAS_STAT_PATH_BAL(i+1) ≤ +110 dB


� RMSpt5 = TAB_PAR_MEAS_LEV = Table of 9 parameters MEAS_STAT_LEVi

� RMSpt4 = TAB_PAR_MEAS_PATH_BALANCE = Table of 9 parameters MEAS_STAT_PATH_BALi

� The Path Balance is computed by the BTS from each Measurement Result message as the difference between:

� Path loss on the uplink: received level by the BTS - MS power level

� Path loss on the downlink: received level by the MS - BS power level

� where the BTS power level is computed as the BTS nominal power minus by the BTS power relative level.

� Therefore the Path balance is computed as follows:

� Path Balance = (RXLEV_UL - MS_TXPWR) - (RXLEV_DL - [BTS_MAX_OUTPUT_POWER - abs(BS_TXPWR)])

� where

� RXLEV_UL is the received signal levels measured by the BTS on the uplink path (in dBm).

� MS_TXPWR is the MS transmitted power converted by the BTS from the MS power level into dBm value according to the frequency band of the TRX.

� BS_TXPWR is the BTS transmitted power offset defined relatively to the maximum absolute output power of the BTS (negative value in dB).

� BTS_MAX_OUTPUT_POWER is the maximum power of the BTS after Combiner (in dBm).

� RXLEV_DL is the received signal levels measured by the MS on the downlink path (in dBm).

� NOTE: Additional asymetric DL loss (external combiner) or UL gain (TMA) are not taken into account in the computation, so they must be considered when interpreting the RMS results.


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� TA_STAT: threshold on the timing advance value defining a priori the range of the cell (0 to 64 bits)

� MEAS_STAT_S1 to MEAS_STAT_S9: 9 thresholds on the BTS Radio Link Counter S value defining 10 S bands

� 0 < MEAS_STAT_S(i) ≤ MEAS_STAT_S(i+1) ≤ 128 SACCH mfr

� S: counter managed by the BTS on a per call basis

� S = RADIOLINK_TIMEOUT_BS if good radio conditions

� S decremented if bad radio conditions

� The BSS triggers a call drop when S = 0


� RMSpt3 = TAB_PAR_MEAS_STAT_S = Table of 9 parameters MEAS_STAT_Si

� RMSpb = PAR_TA_STAT

� Recall on the Uplink Radio Link Supervision procedure:

� For each active dedicated radio channel in a cell, a counter “S” called Radio Link Counter is:

� decremented by 1 by the BTS each time an SACCH measurement from the mobile cannot be decoded

(SACCH_BFI=1).

� incremented by 2 by the BTS each time a valid SACCH measurement is received from the mobile

(SACCH_BFI=0).

� Initial value of S = RADIOLINK_TIMEOUT_BS (cell parameter)

� if S reaches N_BSTXPWR_M, a radio link recovery is triggered (BTS and MS power increased at their maximum).

� if S reaches 0, a Radio Link Failure is triggered (channel drop).

� Therefore the value of S gives a measure of the “quality” of the radio uplink.


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� MEAS_STAT_BFI1 to MEAS_STAT_BFI9: 9 thresholds on the number of consecutive speech frames with BFI set to 1 defining 10 BFI bands

� 0 < MEAS_STAT_BFI(i) ≤ MEAS_STAT_BFI(i+1) ≤ 25 speech frame

� The BTS decodes 24 speech frames (sf) from 1 uplink SACCH multi-frame:

and 1 SACCH frame (or block)

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

S

A

C

C

H

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

SACCH mfrTDMA: 4,616ms

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

S

A

C

C

H

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

S

A

C

C

H

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

S

A

C

C

H

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

Sf 1 Sf 2 Sf 3 Sf 4 Sf 5 Sf 6 Sf 7 Sf 8 Sf 9 Sf 10 Sf 11 Sf 12 Sf 13 Sf 14 Sf 15 Sf 16 Sf 17 Sf 18 Sf 19 Sf 20 Sf 21 Sf 22 Sf 23 Sf 24


� RMSpt2 = TAB_PAR_MEAS_STAT_BFI = Table of 9 parameters MEAS_STAT_BFIi

� Consecutive Frame Erasure (CFE):

� MEAS_STAT_BFIi parameters define 9 intervals of cumulated numbers of consecutive speech frames which have a Bad

Frame Indicator value set to 1 (it means that the speech frame is considered as erroneous by the BTS).

As the TC will erase speech frames for which a Bad Frame Indicator flag (BFI) has been set to the value 1 by the BTS, a

BFI is used in the RMS counters description whereas the CFE is used in the RMS indicators defined in the RNO tool.

� Note: By default, a BFI relates to a speech frame. When considering SACCH measurement, SACCH_BFI should be used.





6.5.3 Radio quality counters


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6.5.3 Radio quality counters RMS counters (1/7)


�� TPR_RXQUAL_UL_RXLEV_ULTPR_RXQUAL_UL_RXLEV_UL: matrix of 8x10 elements UL(RXQUAL i, RXLEV band j), each element is made up of:

� Samplesij: norm of number of measurement result samples in which UL RxQual is equal to i and UL RxLev is reported in RXLEV band j

� MS PWR levelij: average value of MS power (in dBm) from pwr levels reported in these samples

� Timing Advanceij: average value of TAs reported in these samples

�� TMR_RXQUAL_UL_RXLEV_ULTMR_RXQUAL_UL_RXLEV_UL: vector of 10 elements ULRXQUAL(RXLEV band j), each element is made up of:

� the maximum value of the 8 real numbers of samples in which UL RxQual is equal to i (i=0 to 7) and UL RxLev is reported in RXLEV band j

RMS3a=TPR_RXQUAL_UL_RXLEV_UL RMS3b=TMR_RXQUAL_UL_RXLEV_UL

The real number of Measurement Results in which UL RxQual is equal to i and UL RxLev is in RXLEV band j, is equal to: S(RXQUAL i, RXLEV band j) x Max j / 254 TPR_RXQUAL_UL_RXLEV_UL(i,j) x TMR_RXQUAL_UL_RXLEV_UL(j) / 254


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�� TPR_RXQUAL_DL_RXLEV_DLTPR_RXQUAL_DL_RXLEV_DL: matrix of 8x10 elements DL(RXQUAL i, RXLEV band j), each element is made up of:

� Samplesij: norm of number of measurement result samples in which DL RxQual is equal to i and DL RxLev is reported in RXLEV band j

� BS PWR levelij: average value of BS power (in dBm) from pwr levels reported in these samples

� Timing Advanceij: average value of TAs reported in these samples

�� TMR_RXQUAL_DL_RXLEV_DLTMR_RXQUAL_DL_RXLEV_DL: vector of 10 elements DLRXQUAL(RXLEV band j), each element is made up of:

� the maximum value of the 8 real numbers of samples in which DL RxQual is equal to i (i=0 to 7) and DL RxLev is reported in RXLEV band j

RMS4a=TPR_RXQUAL_DL_RXLEV_DL RMS4b=TMR_RXQUAL_DL_RXLEV_DL

The real number of Measurement Results in which DL The real number of Measurement Results in which DL The real number of Measurement Results in which DL The real number of Measurement Results in which DL RxQualRxQualRxQualRxQual is equal to i and DL is equal to i and DL is equal to i and DL is equal to i and DL RxLevRxLevRxLevRxLev is in RXLEV band j, is in RXLEV band j, is in RXLEV band j, is in RXLEV band j, is equal to:is equal to:is equal to:is equal to:S(RXQUAL i, RXLEV band j) x Max j / 254 S(RXQUAL i, RXLEV band j) x Max j / 254 S(RXQUAL i, RXLEV band j) x Max j / 254 S(RXQUAL i, RXLEV band j) x Max j / 254 TPR_RXQUAL_DL_RXLEV_DL(i,j) x TMR_TPR_RXQUAL_DL_RXLEV_DL(i,j) x TMR_TPR_RXQUAL_DL_RXLEV_DL(i,j) x TMR_TPR_RXQUAL_DL_RXLEV_DL(i,j) x TMR_RXQUAL_DL_RXLEV_DL(j) / 254_DL_RXLEV_DL(j) / 254_DL_RXLEV_DL(j) / 254_DL_RXLEV_DL(j) / 254


1.264



�� TPR_PATH_BALANCETPR_PATH_BALANCE: vector of 10 elements UL/DL(PATH BALANCE band j), each element is made up of:

� the norm of number of measurement result samples for which the computed Path Balance is in PATH BALANCE band j

�� MAX_PATH_BALANCEMAX_PATH_BALANCE:

� the maximum value of the 10 real numbers of samples for which the computed Path Balance is in PATH BALANCE band j (j=1 to 10)

RMS7a=TPR_PATH_BALANCE RMS7b=MAX_PATH_BALANCE

The real number of Measurement Results in which Path balance is in PATH BALANCE band j, is equal to: S(PATH BALANCE band j) x Max / 254 TPR_PATH_BALANCE(j) x MAX_PATH_BALANCE / 254


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�� TPR_RADIO_LINKTPR_RADIO_LINK: vector of 10 elements UL(S band j), each element is made up of:

� the norm of number of measurement result samples for which the Uplink Radio Link Counter is in S band j

�� MAX_RADIO_LINKMAX_RADIO_LINK:

� the maximum value of the 10 real numbers of samples for which the Uplink Radio Link Counter is in S band j (j=1 to 10)

RMS6a=TPR_RADIO_LINK RMS6b=MAX_RADIO_LINK

The real number of Measurement Results in which Uplink Radio Link Counter is in S band j, is equal to: S(S band j) x Max / 254 TPR_RADIO_LINK(j) x MAX_RADIO_LINK / 254


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�� TPR_BFI_RXLEV_ULTPR_BFI_RXLEV_UL: matrix of 10x10 elements UL(BFI i, RXLEV band j), each element is made up of:

� the norm of number of SACCH multi-frames in which the number of consecutive speech frames with BFIs set to 1 is in BFI band i and UL RxLev reported in the corresponding measurement results is in RXLEV band j

�� TMR_BFI_RXLEV_ULTMR_BFI_RXLEV_UL: vector of 10 elements ULBFI(RXLEV band j), each element is made up of:

� the maximum value of the 10 real numbers of SACCH multi-frames in which the number of consecutive speech frames with BFIs set to 1 is in BFI band i (i=0 to 9) and UL RxLevreported in the corresponding measurement results is in RXLEV band j

RMS5a=TPR_BFI_RXLEV_UL RMS5b= TPM_BFI_RXLEV_UL

The real number of Measurement Results in which the number of consecutive speech frames with BFIs set to 1 is in BFI band i and UL RxLev is in RXLEV band j, is equal to: S(BFI i, RXLEV band j) x Max j / 254 TPR_BFI_RXLEV_UL(i,j) x TMR_BFI_RXLEV_UL(j) / 254


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� The BTS increments the BFI (or CFE) counter as soon as consecutive speech frames cannot be decoded

� isolated speech frames with BFIs set to 1 are not counted

� sequences of not decoded speech frames are cumulated

SACCH mfr

CFE

0 0 0 0 0 0 0 0 1 2 3 3 3 3 4 4 4 5 6 6 6 6 6 7 7

BFI

Sf 1 Sf 2 Sf 3 Sf 4 Sf 5 Sf 6 Sf 7 Sf 8 Sf 9 Sf 10 Sf 11 Sf 12 Sf 13 Sf 14 Sf 15 Sf 16 Sf 17 Sf 18 Sf 19 Sf 20 Sf 21 Sf 22 Sf 23 Sf 24 SACCH f.

0 0 0 1 0 0 0 1 1 1 1 0 0 1 1 0 1 1 1 0 1 0 1 1 0

RxLev UL

10 11 9 12 12 11 11 10 3 2 0 8 9 5 3 7 2 1 2 7 3 8 2 3 5

Av_RxLev_UL= - 110 + INT[(10+11+9+12+12+11+11+10+3+2+0+8+9+5+3+7+2+1+2+7+3+8+2+3+5)/25]

= -104 dBm


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�� PERC_TA_GT_TA_STATPERC_TA_GT_TA_STAT:

� percentage of measurement results reported with a Timing Advance value > TA_STAT parameter

�� MAX_TAMAX_TA:

� maximum value of Timing Advance among all TA values reported in the measurement results used for RMS

� Corresponding RMS counter numbers:

� RMS36 = PERC_TA_GT_TA_STAT

� RMS37 = MAX_TA




6.6 C/I statistics




6.6 C/I statistics

6.6.1 C/I Generalities


1.271

6.6.1 C/I Generalities Storage and computation methods

� In order to provide an efficient storage, the "vector method" already seen for previous RMS statistics will be used for C/I counters

� C/I expressed in logarithmic scale (dB)

� (C/I)dB = CdBm - IdBm = 10 log10(CmW) - 10 log10(ImW) = 10 log10(C/I)mW




6.6 C/I statistics

6.6.2 C/I Parameters


1.273

6.6.2 C/I parameters RMS parameters

C/I statistics

parameters defining intervals for C/I statistics

� MEAS_STAT_C_I1 to MEAS_STAT_C_I9: 9 thresholds on the Carrier/Interference ratio defining 10 C/I bands

� -63 < MEAS_STAT_C_I(i) ≤ MEAS_STAT_C_I(i+1) ≤ +63 dB

� EN_BALANCED_CI: boolean indicating if the C/I value reported by the BTS is balanced or not

� NEIGB_CELL_ID: (BCCH,BSIC) of the neighboring cell for which the C/I statistics per neighboring cell are reported

� Frequency ARFCN: ARFCN of the frequency for which the C/I statistics per MAFA frequency are reported

Annex 2


� RMSpt1 = TAB_PAR_MEAS_STAT_C/I = Table of 9 parameters MEAS_STAT_C_Ii

� RMSpa = PAR_EN_BALANCED_CI

� RMSp80 = NEIGB_CELL_ID

� RMSp90 = Frequency ARFCN

� For C/I statistics per neighboring cell:

� The C/I ratio is computed by the BTS from each Measurement Result message as the difference between:

� the downlink signal level measured by the MS on the serving TCH channel = C (dBm)

� the downlink signal level measured by the MS on the neighboring BCCH channel = I (dBm)

� Two computation formulae may be used taking into account a corrective factor in case DL Power Control is used in the serving cell:

� If EN_BALANCED_CI = False

� then C/I (dB) = RXLEV_DL (dBm) - RXLEV_NCELL (dBm)

� else C/I (dB) = RXLEV_DL + abs(BS_TXPWR - BS_TXPWR_MAX) - RXLEV_NCELL

� The expression (RXLEV_DL + abs(BS_TXPWR - BS_TXPWR_MAX)) can be seen as a kind of normalized received power level in case the BTS would always have used the maximum allowed transmit power level on the TCH channel.

� For C/I statistics per MAFA frequency:

� The C/I ratio is computed by the BTS from each Extended Measurement Report message in the same way as the C/I ratio per neighboring cell.




6.6 C/I statistics

6.6.3 C/I Counters


1.275

6.6.3 C/I counters RMS counters

C/I statistics per neighboring cell

�� TPR_CINTPR_CIN: vector of 10 elements C/In(C/I band j), each element is made up of:

� the norm of number of measurement result samples for which the computed Carrier/Interference ratio is in C/I band j

�� MR_CINMR_CIN:

� maximum value of the 10 real numbers of samples for which the computed Carrier/Interference ratio is in C/I band j (j=1 to10)

TPR_CINTPR_CIN and MR_CINMR_CIN counters are provided for up to 42 neighboring cells

RMS8a=TPR_CIN RMS8b=TMR_CIN

For each reported neighboring cell (BCCH/BSIC):

the Real number of Measurement Results for which the computed Carrier/Interference ratio is in C/I band j, is

equal to:

S(C/I band j) x Max / 254

TPR_CIN(j) x TMR_CIN / 254

For each declared/reported neighboring cell, the identification of this cell shall be done as follows:BCCH_ARFCN and BSIC. The BCCH ARFCN is deduced in the BTS from the BCCH frequency index and the list of indexed frequencies (sent by the BSC at the beginning of the RMS job). The RMS results report shall include all reported neighboring cells. Some of them correspond to known cells at the BSS level (i.e. their BSIC matches what is expected at the BSC side) but some of them are unknown (their BSIC does not match). However, the BTS will handle the same for both cases.The list of frequencies to be monitored by the mobile is limited to 33 but due to ‘resurgence’, the same frequency can be reported several times (each time with a different BSIC). If the number of reported cells is above the dimensioning limit (maximum 42 CI-vectors are reported), the extra new reported frequencies are not taken into account anymore. In the result report, the related overflow indicator is set accordingly.


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6.6.3 C/I counters RMS counters

C/I statistics per MAFA frequency

�� TPR_CIFTPR_CIF: vector of 10 elements C/If(C/I band j), each element is made up of:

� the norm of number of Extended Measurement Results samples for which the computed Carrier/Interference ratio is in C/I band j

�� MR_CIFMR_CIF:

� maximum value of the 10 real numbers of samples for which the computed Carrier/Interference ratio is in C/I band j (j=1 to10)

TPR_CIFTPR_CIF and MR_CIFMR_CIF counters are provided for up to 21 frequencies (serving cell BCCH + 20 MAFA frequencies)

RMS9a=TPR_CIF RMS9b=TMR_CIF

For each reported MAFA frequency (ARFCN): For each reported MAFA frequency (ARFCN): For each reported MAFA frequency (ARFCN): For each reported MAFA frequency (ARFCN): the Real number of Extended Measurement Results for which the cothe Real number of Extended Measurement Results for which the cothe Real number of Extended Measurement Results for which the cothe Real number of Extended Measurement Results for which the computed Carrier/Interference ratio is in mputed Carrier/Interference ratio is in mputed Carrier/Interference ratio is in mputed Carrier/Interference ratio is in C/I band j, is equal to: C/I band j, is equal to: C/I band j, is equal to: C/I band j, is equal to: S(C/I band j) x Max / 254 S(C/I band j) x Max / 254 S(C/I band j) x Max / 254 S(C/I band j) x Max / 254 TPR_CIF(j) x TMR_CIF / 254TPR_CIF(j) x TMR_CIF / 254TPR_CIF(j) x TMR_CIF / 254TPR_CIF(j) x TMR_CIF / 254

For each reported MAFA frequency, the identification of this frequency shall be done as follows: Frequency ARFCN .

In case of a frequency reported via an Extended Measurement Reporting, no BSIC is required: the frequency ARFCN is not directly linked to a BCCH frequency. The ARFCN value of the frequency is deduced in the BTS from the place of the measurement in the EXTENDED_ MEASUREMENT_REPORT and from the ordered frequency list in the Extended Measurement Order. This list is built by the OMC-R and passed via BSC to BTS at the beginning of the RMS job.

The maximum number of frequencies in the order (EMO) is the maximum defined in GSM (=21). Hence the maximum in the report is 21 also. When in exceptional cases, more results are available (future expansion in GSM), only the first 21 are reported.

The BCCH frequency of the serving cell shall always be part of the EMO-frequency list.




6.7 RMS indicators usage


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6.7 RMS indicators usage Voice quality problem

Suspecting a Voice Quality problem RMS indicators

� Percentage of Noisy calls

� FER is more reliable than RXQUAL to assess VQ

� Noisy calls indicators can also be computed from FER measurements

� Noisy calls with bad or good FER

� Calls not detected as noisy but with bad FER

Voice Quality indicators are

based on calls

Noisy calls are associated

with a cause of

bad coverage, interference or

with an undefined cause

� The fact that FER measurements are more reliable than RXQUAL ones to assess the VQ is even more true when using Slow Frequency Hopping. In this case, RXQUAL values are not anymore correlated to Voice Quality as perceived by the end user.

� FER measurements are available for the uplink path only.


� Number of Noisy calls suffering from problem of bad coverage on the uplink pathRMVQULVN = RMS_call_noisy_UL_bad_coverage

� Number of Noisy calls suffering from problem of interference on the uplink pathRMVQUIFN = RMS_call_noisy_UL_interference

� Number of Noisy calls suffering from problem of interference and bad coverage considered together on the uplink pathRMVQUUKN = RMS_call_noisy_UL_undefined

� Rate of Noisy calls suffering from problems of interference or/and bad coverage on the uplink pathRMVQUNOR = RMS_call_noisy_UL_rate

� Note: The 4 indicators above can be provided for Noisy calls suffering of VQ problems on the dowlink path.

� Rate of Noisy calls but with good FER measurements on the uplink pathRMVQFEGR = RMS_call_noisy_good_FER_rate

� Rate of Noisy calls and also with bad FER measurements on the uplink pathRMVQFEBR = RMS_call_noisy_bad_FER_rate

� Rate of calls with fair quality measurements but with bad FER measurements on the uplink pathRMVQFEAR = RMS_call_abnormal_bad_FER_rate

� This last indicator can be used in order to tune the RMS VQ parameters used to characterize a call as Noisy.


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6.7 RMS indicators usage Cell coverage problem

Suspecting a cell coverage problem

� Distribution of samples per RxQual value and RxLev band

� Distribution of samples per RxLev band

Not acceptable

coverage limit:

Too low level

Too bad quality

� A coverage problem is observed when a significant amount of the traffic of a cell is suffering from both low level and bad quality (RxQual).

� To confirm the distribution of samples per RXLEV band, should be also considered to know the proportion of calls which are experiencing a low signal level.

� If a lot of samples of low level and bad quality are observed for only a sub-part of the TRXs (can be one only) then a BTS hardware problem or a problem on the aerials should be suspected.

� If all the TRXs are experiencing a lot of samples of low level and bad quality then a coverage problem shall be suspected.



� Vector of Percentage of Samples per DL RxLev bandRMQLDLVDV = RMS_DL_RxLevel_distrib

� Vector of Percentage of Samples per DL RxQual bandRMQLDQUDV = RMS_DL_RxQuality_distrib


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6.7 RMS indicators usage Cell coverage problem

Suspecting a cell coverage problem RMS indicators

� Average TA values per RxQual value and RxLev band

Not acceptable

coverage limit:

Too low level

Too bad quality

Acceptable coverage limit:

Sufficient level and good quality

% of TA value over TA threshold

has also to be considered

� In order to know if the coverage problem is due to a big amount of traffic at the cell border or rather to indoor calls, the average TA value per RXQUAL value and RXLEV band as well as the Percentage of TA values over the TA threshold should be observed.

� Matrix of Average TA per UL RxQual value and per UL RxLev bandRMQLUTAM = RMS_UL_RxQuality_RxLevel_TimingAdvance

� Rate of Measurements Results whose TA is greater than the TA thresholdRMTAGTR = RMS_TimingAdvance_greater_threshold_rate

� Maximum TA value of all values reported in Measurement Results RMTAMXN = RMS_TimingAdvance_max


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6.7 RMS indicators usage RMS Exercise 1

� Give the list of the RMS counters and parameters used in the 3 previous slides

Time allowed:

10 minutes


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6.7 RMS indicators usage RMS exercise 2

� What does this graph represent?

� Interpret this graph

Time allowed:

10 minutes


� Vector of the Number of Measurement Results per Path Balance bandRMPBV = RMS_PathBalance_sample

� Average Path Balance valueRMPBAN = RMS_PathBalance_avg

� A fair average Path Balance at Cell level can hide a bad value for one TRX.


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6.7 RMS indicators usage Cell interference problem

Suspecting a cell interference problem

� Number of samples per RxQual value and RxLev band

Average DL RxQuality = 0.34

RMS results show no problemof radio link quality in this cell

Average RxQual value per RxLev

band has also to be considered



� Vector of Average DL RxQual per RxLev bandRMQLDQUAV = RMS_DL_RxQuality_avg_per_RxLevel

� Average DL RxQualityRMQLDQUAN = RMS_DL_RxQuality_avg


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Average RxQual value per RxLev band has also to be considered

Average DL RxQuality = 2.81

Time allowed:

10 minutes



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Time allowed:

15 minutes � Interpret this graph


� Matrix of the Number of Measurements Results per CFE band (or BFI band) and per UL RxLev band RMFEM = RMS_UL_ConsecutiveFrameErasure_RxLevel_sample

� Vector of the Average number of Consecutive Frame Erasure per UL RxLev bandRMFEBFAV = RMS_UL_ConsecutiveFrameErasure_avg_per_RxLevel

� Vector of the Average UL RxQual per RxLev bandRMQLUQUAV = RMS_UL_RxQuality_avg_per_RxLevel


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Time allowed:

10 minutes


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� Compute the RMS counters and indicators in the file

Time allowed:

10 minutes




6.8 Additional information


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6.8 Additional information RMS counters (1/3)

Counters used for:

� post-processing the RMS results provided per TRX

� TOT_SEIZ_TCH: number of TCH channels successfully seized by the MS

� TOT_MEAS: number of Measurement Results used for RMS

� TOT_MEAS_L1INFO_NOL3INFO: number of Measurement Results used for RMS statistics for which Layer 1 info is present but Layer 3 is missing

� TOT_MEAS_DTX_UL: number of Measurement Results used for RMS statistics for which DTX UL was used in the corresponding SACCH mfr

� TOT_MEAS_DTX_DL: number of Measurement Results used for RMS statistics for which DTX DL was used in the corresponding SACCH mfr

� TOT_EMR: number of Extended Measurement Results used for RMS statistics


� RMS31 = TOT_SEIZ_TCH

� RMS32 = TOT_MEAS

� RMS33 = TOT_MEAS_L1INFO_NOL3INFO

� RMS34 = TOT_MEAS_DTX_UL

� RMS35 = TOT_MEAS_DTX_DL

� RMS38 = TOT_EMR

� Note:

� If during an SACCH measurement, DTX is applied on the uplink path (DTX_UL =1), the counters on consecutive BFIs(RMS5a, RMS5b) shall not be incremented and the corresponding measurement result shall not be taken into account in these RMS counters.

� If during an SACCH measurement, DTX is applied on the uplink path (DTX_UL = 1), the FER measurement does not take place.


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Counters used for:

� interpreting the RMS results provided per TRX

� TRE_BAND: frequency band of the TRX

� BS_TX_PWRMAX: effective maximum output power of the BTS on any channel of the TRX as an offset from the maximum absolute outputpower (in dB)

� MS_TX_PWRMAX: effective maximum output power of the MS using any channel of the TRX (in dBm)

� IND_TRE_OVERLOAD: boolean indicating if the TRE handling the TRX function has experienced a data loss due to a processor overload during the RMS campaign

� IND_RMS_RESTARTED: boolean indicating if the RMS job has been restarted on the concerned TRE during the RMS campaign due to a modification of the RMS parameter values or a TRE reset

� Corresponding RMS counter numbers: RMS20 = TRE_BAND

� RMSpw1 = BS_TX_PWRMAX

� RMSpw2 = MS_TX_PWRMAX

� RMS21 = IND_TRE_OVERLOAD

� RMS22 = IND_RMS_RESTARTED


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Counters used for:

� interpreting the C/I RMS results provided per TRX

� IND_CI_PARTIAL_OBSERVATION: made up of 2 booleans indicating

that:

� C/In computation has been restarted due to the modification of the list of neighboring cells during the RMS campaign

� C/If computation has been restarted due to the modification of the list of MAFA frequencies during the RMS campaign

� IND_CI_OVERFLOW: boolean indicating that the upper limit of 42 C/I

sets of counters has been exceeded (each new reported neighboring cell

(BCCH, BSIC) has not been taken into account in RMS statistics)


� RMS23 = IND_CI_PARTIAL_OBSERVATION

� RMS24 = IND_CI_OVERFLOW


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7 Traffic indicatorsSession presentation

� Objective: to be able to describe BSS traffic indicators used for radio resource dimensioning

� Program:

7.1 Call mix definition

7.2 Basis of traffic theory

7.3 TCH resource allocation indicators

7.4 Resource occupancy indicators

7.5 Traffic model indicators

7.6 Preemption indicators




7.1 Call mix definition


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7.1 Call mix definitionGSM transactions

� In a GSM Network, there are a lot of different transactions :

� location update: periodic, new updating, ~imsi_attach, ~imsi_detach

� Hand Over (intra-cell, internal, external, etc.)

� SMS (Short Message Service, originating or terminating)

� SS (Supplementary Service)

� Paging

� and also Originating and Terminating calls, etc.

� and so on (data, SMS-CB, etc.)

� In a GSM network, telecom procedures involve different kinds of resource in the BSS:

� Location Update: RACH, AGCH, SDCCH and SCCP

� Originated Call: RACH, AGCH, SDCCH, TCH and SCCP

� Terminated Call: PCH, RACH, AGCH, SDCCH, TCH and SCCP

� Handover: TCH, SCCP

� etc.


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7.1 Call mix definitionGSM transactions

� One can quantify the number of each transaction per hour

� For example, for one cell, one can measure:

� 900 calls (600 TCs, 300 OCs)

� 3600 LUs (any type)

� 1350 HOs (900 internal, 450 external)

� 100 SMSs

� 5 SSs

� 6000 pagings

With the following characteristics

� mean call duration on TCH: 50 seconds

� mean SDCCH duration: 3.2 seconds

� A Call mix can be defined through:

� data given by the Marketing team.

� data measured from the living network.

� Before network design, a Call Mix is assessed from Marketing Studies or observations from other networks.

� After commercial opening, a Call Mix is measured from the real traffic.

� Caution: Call duration means here TCH duration. The duration of a call from call setup to call release is an NSS notion.


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7.1 Call mix definitionExample

� Set of such measurements is called "call mix"

� sometimes improperly called "traffic model"

� Usually presented in the following way:

� Calls /hour : 900 (2/3 TC)

� LU/call : 4

� HO/Call : 1.5 (2/3 internal, 1/3 external)

� SMS/Call : 11 %

� SS/call : 5 %

� Paging/hour : 6000

� mean call duration on TCH : 90 seconds

� mean SDCCH duration : 4.2 seconds

� After commercial opening, the number of calls per hour will be measured from traffic counters.

� Usually the Marketing team will provide:

� on a per geographical area or morphostructure basis:

� the traffic per km2 (in Erlang),

� the traffic per subscriber (in mErl).

� the number of calls per hour.


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7.1 Call mix definitionVariation

� A call mix is varying a lot:

� from a cell to another

�TCH traffic (induced by subscribers)

� number of LU/call and HO/call (induced by network design)

� from one hour to another

� by default: busy hour

� from one year to another

�modification of traffic intensity and distribution

� On some university campus, an SMS/call is often higher than the average.


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7.1 Call mix definitionUsage

� Interests of call mix: Input data for dimensioning

� Cell and BSC resources dimensioning

�RTCH, SDCCH, TTCH, BTS, BSC and MSC CPU processor

� Some examples of "risky" call mix

� too many LU/Calls: SDCCH congestion, TCU load, MSC overload

� too many HO/calls: speech quality, call drop, DTC load

� too many calls: TCH congestion

� too many pagings: DTC processor load, PCH congestion

� A Call Mix will be used at Radio Network Design and Radio Network Planning stages in order to define the capacity of the network(number of sites, TRXs per site, radio configuration, number of Abis-PCM, A-PCM).

� When the network is in operation, a Call Mix is used in order to anticipate network extension or re-dimensioning.


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7.1 Call mix definitionAdvises

� Some advises

� LU/CALL: 1 is "good", 2 is "bad", 4 and more can be dangerous

� beware of the Network or BSC averages which can hide critical cells

� HO/Call: less critical (1 is good)

� 2 or 3 is not a direct problem, but the trend has to be monitored

� Call: to be checked with an Erlang table (seen in next session)


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7.1 Call mix definitionExercise

Training exercise

� Compute the call mix of a cell according the following information

� 256 call/hour

� 1300 LU/hour

� 450 HO/hour

� Is it complete?

� What are the risks of such a call mix?




7.2 Basis of traffic theory


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7.2 Basis of traffic theory Erlang definition

� ERLANG: unit used to quantify traffic (intensity)

� T = (resource usage duration) / (total observation duration) [ERLANG]

� Example:

� For 1 TCH, observed during 1 hour

� one can observe 2 calls: 1 of 80 seconds and 1 of 100 seconds

�T = (80+100)/3600 = 0.05 ERLANG


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7.2 Basis of traffic theory Erlang from call mix

CALL MIX => ERLANG

� Call mix example:

� 350 call/hour

� 3 LU/call

� TCH mean call duration: 85 seconds

� SDCCH mean duration: 4.5 seconds

� Computation of Carried Erlang

�TCH = (350*85)/3600: 8.26 ERLANGS

�SDCCH = [ (350+350*3) * 4.5 ] / 3600 = 1.75 Erlang


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7.2 Basis of traffic theory Erlang B law

� In a Telecom system, the call arrival frequency is ruled by the POISSON law

� Erlang B law: relationship between:

� offered traffic

� number of resources

� blocking rate

call/second

0

1

2

3

4

5

6

7

8

9

10

1 5 9

13

17

21

25

29

33

37

41

45

49

53

57

61

65

69

73

77

81

85

89

93

97

call/second

0

1

2

3

4

5

6

7

8

9

10

1 5 9

13

17

21

25

29

33

37

41

45

49

53

57

61

65

69

73

77

81

85

89

93

97


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� The call request arrival rate (and leaving) is not stable

� number of resources = average number of requests * mean duration

� is sometimes not sufficient => probability of blocking

� => Erlang B law

� Pblock: blocking probability

� N: number of resources

� E: offered traffic [Erlang]

� Good approximation when the blocking rateis low (< 5 %)

7.2 Basis of traffic theory Erlang B law

Telecom system

OfferedCarried

Rejected

P b lo ckN

k

N

k

k

N

E

E=

=∑

!

!0

� The Erlang B law is not fully accurate since it assumes that:

� the subscriber requests are not queued which is not always the case (TCH queued in the BSC),

� the subscriber does not repeat his call request if rejected, which is almost never the case.

� Therefore the higher the blocking rate the worse is the approximation of the Erlang B law.

� The Erlang C law modelizes better the TCH resource usage of the BSS since it takes into account the queuing.

� However the Erlang C law is never used since parameters like size of the queue and time spent into the queue have to be tuned.


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7.2 Basis of traffic theory Erlang B formulae

� There are two different ways to use this law

� Using Abacus

� Using SW (here Excel)

�Pblock = f (T, Nc)

�Offered = f (Nc, Pblock)

�Channels = f (T, Pblock)


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7.2 Basis of traffic theory Erlang B abacus


1.309

� Example: 1 cell with 8 TRXs, with 60 TCH channels

� Maximum blocking rate: 2 %

�Erlang law: 50 Offered Erlang

� 83 % of TCH resources used to reach 2% of blocking

7.2 Basis of traffic theory Erlang B example


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� But be careful, the Erlang B law is not linear:

� In B4, we use for example a combined BCCH with a micro BTS.

� 4 SDCCHs, Pblock = 2% => T = 1.1 E

� 25% resources used to reach 2% blocking

� In B5, if we decide to provide SMSCB (Cell Broadcast information), 1 SDCCH stolen for CBCH

� 3 SDCCH, Pblock = 2% => T = 0.6 E

� 25 % resources less => 50 % Traffic less!!

7.2 Basis of traffic theory Non linearity of Erlang B


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� Given an Offered traffic, compute the number of TRXs (and SDCCH) needed to carry it => What is the accepted blocking rate?

� default blocking rate

� RTCH: 2 %

� SDCCH: 0.5 %

� (for BSC TTCH: 0.1%)

7.2 Basis of traffic theory Cell dimensioning

� The Erlang B law is less relevant for SDCCH dimensioning since SDCCH traffic cannot be modelized like TCH traffic. Indeed SDCCH is not only due to subscriber traffic but also to Location Update, SMS, IMSI Detach, etc.

� For SDCCH dimensioning, some typical configurations are used according to the number of TRXs in the cell, the LA plan.


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� Cell dimensioning from call mix (bid, architecture)

� to handle an offered traffic of 12 Erlangs (RTCH), compute the number of channels, then the number of TRXs

�Channels (12;2%) = 19

� example: 3 TRXs, 21 TCHs, 1 BCCH, 2 SDCCHs/8

7.2 Basis of traffic theory Dimensioning "a priori"


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� Cell dimensioning from measurement (re-planning)

� one is measuring a traffic of 15 Erlangs, with a blocking rate of 10 %

� how to dimension the cell?

�Offered traffic = 15 / (1-10%) = 16.7 Erlangs!!!!

�Channels (16.7;2%) -> 25 TCHs -> 4 TRXs needed

7.2 Basis of traffic theory Dimensioning "a posteriori"


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� Forecast traffic

� traffic forecasting must be computed according to the offered traffic

�not directly on the measured traffic

� In order to plan the necessary actions soon enough, one must compute regularly the date when the traffic of a cell will become critical

� Critical traffic

� critical traffic: when the offered traffic will induce 2% of blocking

� traffic capacity of a cell = critical traffic of this cell

7.2 Basis of traffic theory Forecast / Critical traffic


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7.2 Basis of traffic theory Exercise

� Training exercise: complete the form to get less than 2% of blocking

cellcellcellcell call call call call mix infomix infomix infomix info Erlang TCHErlang TCHErlang TCHErlang TCHOffered Offered Offered Offered traffictraffictraffictraffic

traffic traffic traffic traffic forecastforecastforecastforecast proposed proposed proposed proposed configconfigconfigconfig

12, 743 450 call/hourmean TCH call duration : 80secblocking rate TCH : 0.8%

10,08 Erlang TCH 30 % offered trafficincrease

13,1 Erlang TCH - > 20 TCH3 TRX

12,675 330 call/hourmean TCH call duration 129secblocking rate 4%

30 % offered trafficincrease

12,865 600 call/hourmean TCH call duration 96secblocking rate 8 %

30 % offered trafficincrease




7.3 TCH resource allocation indicators


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7.3 TCH resource allocation indicators Radio Allocation and Management

� Radio resource allocation and management aim at:

� managing pools of TCH resources by:

� evaluating the load and traffic situation of one cell

� adapting the handling of resources according to these evaluations

� Allocating dedicated radio resources by:

� determining the type of resource to be provided for a request and checking the availability of such resource

� selecting the best resource according to several criteria


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7.3 TCH resource allocation indicators TCH allocation process

TCH request

TCH rejected TCH queued

TCH allocation

TCH selection

channel type (FR,HR,DR)

speech version (FR, HR, EFR, AMR FR, AMR HR)request type (NA or HO)

cell channel type capability

cell codec type capabilitycell load

TCH free?

Queuing?

no yes

no yesTCH pool (FR,DR,HR) selecting criteria

� Inputs for TCH allocation function:

� requirements from the MSC:

channel type (mandatory) is one of the following:

list of preferred speech version (optional):

� GSM full rate speech version 1 = FR

� GSM full rate speech version 2 = EFR

� GSM full rate speech version 3 = AMR FR

� GSM half rate speech version 1 = HR

� GSM half rate speech version 3 = AMR HR

� capabilities of the cell:

� FR TCHs only if only FR TRXs / FR+HR TCHs if some DR TRXs

� codec supported among: FR, EFR, AMR FR, HR, AMR HR

FR Full Rate only

HR Half Rate only

DR FR P NCA Dual Rate Full Rate Preferred No Changes Allowed after first channel allocationas a result of the request

DR FR P CA Dual Rate Full Rate Preferred Changes Allowed after first channel allocation as aresult of the request

DR HR P NCA Dual Rate Half Rate Preferred No Changes Allowed after first channel allocationas a result of the request

DR HR P CA Dual Rate Half Rate Preferred Changes Allowed after first channel allocation as aresult of the request

DR SV P NCA Dual Rate No Changes of channel rate Allowed after first channel allocation as aresult of the request

DR SV P CA Dual Rate Changes of channel rate Allowed after first channel allocation as aresult of the request


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7.3 TCH resource allocation indicators TCH pools

� 3 pools of TCH resources are managed per cell:

� Full Rate TCH pool containing the free resources of FR TRXs

� Dual Rate TCH pool containing the free resources of DR TRXs

� Half Rate TCH pool containing the free HR resources of DR TRXs whose mate HR TCH is busy

� FR channels can be allocated on both FR and DR TRXs whereas HR can only be allocated on DR TRXs


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7.3 TCH resource allocation indicators Cell load influence

� TCH allocation with list of preferred speech versions

� cell load = False

� preferred SV list kept as given by the MSC

� cell load = True

� preferred SV list reordered: HR SV 1st, FR SV 2nd

� TCH allocation without list of preferred speech versions

� if DR HR Preferred request

� try to allocate HR TCH

� if DR FR Preferred request

� try to allocate HR TCH if cell load = True

� try to allocate FR TCH if cell load = False


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7.3 TCH resource allocation indicators HR allocation and release

Example of pool management: HR allocation and release

� HR pool preferred � DR pool selected if HR pool empty

DR HR

Request for a TCH HR Release of a TCH HR

BTS dual rateBTS dual rate

+1 TCH HR (2)

-1 TCH DR

(1)

(2)(2)

(1) : Pool HR not empty

(2) : Pool HR empty

DR HR

-1TCH HR (1)

+ 1TCH DR

(2)

(1)

(1)

(1) : Associated HR free

(2) : Associated HR busy

+1TCH HR (2)

- 1 TCH HR (1)

FR FR


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7.3 TCH resource allocation indicators FR / HR allocation

� FR / HR allocation discrimination for DR HR request

� cell load AV_LOAD() computed from

� load samples = (NB_BUSY_TS / NB_TS) * 100

� non-sliding window (LOAD_EV_PERIOD) averaging process

∑ −

1- RIODLOAD_EV_PE

0 =i

i)e(kLoad_sampl RIODLOAD_EV_PE

1 = AV_LOAD(k)

100%

AV_LOAD()

THR_FR_LOAD_U_SV1

= 80%

THR_FR_LOAD_U_SV3=60%

timeTHR_FR_LOAD_L_SV1=50%

THR_FR_LOAD_L_SV3=40%

� Load samples are computed by the BSC every TCH_INFO_PERIOD = 5 seconds.

� LOAD_EV_PERIOD is the averaging window size for cell load computation. It is equal to 12 but it can be changed at the OMC-R level on a per cel basis.

� Therefore the cell load process has a periodicity of 1mn by default (TCH_INFO_PERIOD*LOAD_EV_PERIOD).

� The allocation of Half rate resources is decided upon the load evaluation in the serving cell.

� AMR HR (HR SV3) offers a better speech quality than HR SV1. The Alcatel BSS offers thus the possibility to define a set of thresholds specific for AMR. If the load increases, AMR HR capable MSs can be the first to be allocated in HR (HR SV3) for load reasons, and if the load still increases, then all the MSs HR capable can be allocated in HR (HR SV1 & HR SV3) for load reasons.

� That is why two variables of load are defined: LOAD_SV3 and LOAD_SV1.

� Each load variable is calculated through its own threshold set: the thresholds related to the variable LOAD_SV3 (THR_FR_LOAD_U_SV3 and THR_FR_LOAD_L_SV3). They are less restrictive than the ones related to the variable LOAD_SV1 (THR_FR_LOAD_U_SV1 and THR_FR_LOAD_L_SV1).

� As a consequence, if the load of the cell increases, then the variable LOAD_SV3 will first equal TRUE, and if the load still increases, the variable LOAD_SV1 will then equal TRUE.

� The variable LOAD_SV1 corresponds to a level of load where it is important to put as many MSs on half rate TCH as possible: HR SV3 or HR SV1.

� The same computation is done to compute LOAD_SV3 with the thresholds: THR_FR_LOAD_U_SV3 and THR_FR_LOAD_L_SV3 with the following relations:

� THR_FR_LOAD_L_SV3 ≤ THR_FR_LOAD_U_SV3

� THR_FR_LOAD_U_SV3 ≤ THR_FR_LOAD_U_SV1

� THR_FR_LOAD_L_SV3 ≤ THR_FR_LOAD_L_SV1

Previous stateAV_LOAD

LOAD_SV1 = FALSE LOAD_SV1 = TRUE

AV_LOAD ≤ THR_FR_LOAD_L_SV1 LOAD_SV1 = FALSE LOAD_SV1 = FALSE

THR_FR_LOAD_L_SV1 <

AV_LOAD ≤

THR_FR_LOAD_U_SV1

LOAD_SV1 = FALSE LOAD_SV1 = TRUE

THR_FR_LOAD_U_SV1 < AV_LOAD LOAD_SV1 = TRUE LOAD_SV1 = TRUE


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7.3 TCH resource allocation indicators TCH pool selection

� TCH allocation without list of preferred speech versions

� FR request: FR pool � DR pool

� HR request: HR pool � DR pool

� DR FR Preferred request:

� cell load=False: FR pool � DR pool � HR pool

� cell load=True: HR pool � DR pool � FR pool

� DR HR Pref. request: HR pool � DR pool � FR pool

� TCH allocation with a list of preferred speech versions

� FR SV: FR pool � DR pool

� HR SV: HR pool � DR pool


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7.3 TCH resource allocation indicators TCH selection

� The TCH is chosen from the selected pool according to the following criteria:

� The Best quality of service for TCH calls is performed by selecting the TCH resources according to the following ordered criteria:

1. Exclusion of TS reserved for GPRS

� In the PDCH groups defined by the BSC to support GPRS traffic, the TS consecutive to the already allocated PDCHs (or the TS on the left side of the PDCH group if no PDCH is allocated) shall be put in the lowest selection priority so that GRPS connections can be more easily established.

2. TS with the highest Trx Preference Mark

� According to the frequency plan, the coverage and interference probability of a cell (or according to measurements), the operator may know which TRX should be a priori favored for TCH selection. For that purpose, it is possible for operators to give a preference mark to each TRX of a cell. This mark is given through the parameters TRX_PREF_MARK (TPM) changeable at OMC-R side per TRX. The range of TRX_PREF_MARK will be from 0 (lowest priority) to 7 (highest priority). The TCH selection function favours the channels with the highest TPM.

3. TS with the biggest Mobile Allocation

� Considering that the number of frequencies is a key factor for the average quality of channels, the TCH selection function favors the TS with the biggest MA (i.e. with the most frequencies in their frequency hopping sequence). This selection criterion is enabled/disabled via the flag EN_MA_SELECTION changeable at the OMC-R side on a per cell basis.

4. TS from the best Interference Band

� Considering that the uplink received level measured by the BTS on an idle channel is a means to assess the quality when in connected mode, the TCH selection function favors the TS belonging to the best Interference Band (IB). Five IBs are defined through 5 parameters INTFBD1 to INTFBD5 where INTFBD(i)< INTFBD(i+1) and INTFBD5 = -47 all changeable at the OMC-R side on a per BTS basis.

5. TS with the highest TS index on the TRX with the highest TRX id

� This last criterion allows to separate the TCH and PDCH allocations so as to avoid CS and PS conflicts on a given TRX. Furthermore, it aims at optimizing radio resource allocations to provide the best throughput for GPRS traffic.

� If more than one TRX is considered, select the TRX with the highest TRX-id.

� If more than one timeslot is candidate, select the candidate TS having the highest timeslot index (at the right side of the TRX).


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7.3 TCH resource allocation indicators MS access

� MS access types distribution (NA only)B8: Accessibility in type 110

� TCH requests from FR only MSTCNARQMN= MC701A

� TCH requests from DR MSTCNARQBN= MC701B

� TCH requests from DR+EFR MSTCNARQTN= MC701C

� TCH requests from AMR MSTCNA3RQTN= MC701D

� TCH requests from Data callsTCNARQDN= MC701E

B8 (See comments)

Modified in B8


� Traffic Load and Traffic Model > TCH traffic > Speech version and Channel type

� These indicators can only be computed if PM Type 1 is activated in B7.

� In B8, the counters needed for these indicators are added to type 110.

� The following indicators are also computed:

� Ratio of TCH normal assignment requests from FR mobiles over all TCH normal assignment requests from all mobile types = TCNARQMTO = MC701A / (MC701A+MC701B+MC701C+MC701D+MC701E)

� Ratio of TCH normal assignment requests from DR mobiles over all TCH normal assignment requests from all mobile types = TCNARQBTO = MC701B / (MC701A+MC701B+MC701C+MC701D+MC701E)

� Ratio of TCH normal assignment requests from DR+EFR mobiles over all TCH normal assignment requests from all mobile types = TCNARQTTO = MC701C / (MC701A+MC701B+MC701C+MC701D+MC701E)

� Ratio of TCH normal assignment requests from AMR mobiles over all TCH normal assignment requests from all mobile types = TCNA3RQTTO = MC701D / (MC701A+MC701B+MC701C+MC701D+MC701E)

� Ratio of TCH normal assignment requests for Data calls over all TCH normal assignment requests from all mobile types = TCNARQDTO = MC701E / (MC701A+MC701B+MC701C+MC701D+MC701E)

� Number of handover intracell attempts with cause 27: "FR to HR channel adaptation due to a good radio quality" on a TCH channel= HCSTAMFN = MC448B

� Number of handover intracell attempts with cause 26: "HR to FR channel adaptation due to a bad radio quality" on a TCH channel= HCSTAMHN = MC448A


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7.3 TCH resource allocation indicators Speech coding version

� Speech coding Version capabilities distribution (NA only)B8: Accessibility in type 110

� TCH allocations with FR SV1TCNACAFN= MC702A

� TCH allocations with HR SV1 TCNACAHN= MC702B

� TCH allocations with FR SV2 (EFR) TCNACAEN= MC702C

� TCH allocations with FR SV3 (AMR FR) TCNA3CAFN= MC704A

� TCH allocations with HR SV3 (AMR HR) TCNA3CAHN= MC704B

� TCH allocations for data call TCNACADN= MC705

B8 (See comments)

Modified in B8

These 2 counters are

new in B8.

In B7, only one

without details: MC704



� These indicators can only be computed if PM Type 1 is activated in B7.

� In B8, the counters needed for these Indicators are added to type 110.

� The following indicators are also computed:

� Ratio of TCH allocations with FR SV1 over all TCH allocations during normal assignment = TCNACAFTO = MC702A / (MC702A+MC702B+MC702C+MC704A+MC704B+MC705)

� Ratio of TCH allocations with HR SV1 over all TCH allocations during normal assignment = TCNACAHTO = MC702B / (MC702A+MC702B+MC702C+MC704A+MC704B+MC705)

� Ratio of TCH allocations with EFR over all TCH allocations during normal assignment = TCNACAETO = MC702C / (MC702A+MC702B+MC702C+MC704A+MC704B+MC705)

� Ratio of TCH allocations with AMR FR over all TCH allocations during normal assignment = TCNA3CAFTO = MC704A / (MC702A+MC702B+MC702C+MC704A+MC704B+MC705)

� Ratio of TCH allocations with AMR HR over all TCH allocations during normal assignment = TCNA3CAHTO = MC704A / (MC702A+MC702B+MC702C+MC704A+MC704B+MC705)

� Ratio of TCH allocations for Data calls over all TCH allocations during normal assignment = TCNACADTO = MC705 / (MC702A+MC702B+MC702C+MC704A+MC704B+MC705)

� Rate of successful TCH allocations with AMR SV over all AMR MS requests= TCNA3SUR = (MC704A+MC704B) / MC701D


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7.3 TCH resource allocation indicators Distributions

� FR/HR calls distribution (NA+HO)

� FR TCH allocation ratioTCAHCAFO = MC370A / (MC370A+MC370B)

� HR TCH allocation ratioTCAHCAHO = MC370B / (MC370A+MC370B)

� NA/HO distribution

� Normal Assignment TCH allocation ratioTCNACAO = MC703 / (MC703 + [MC15A+MC15B])

� Handover TCH allocation ratio TCHOCAO = [MC15A+MC15B] / (MC703 + [MC15A+MC15B])

� TCH allocation distribution per TRX

� Number of TCH allocations for Normal AssignmentTCNACAN = MC703


� Traffic Load and Traffic Model > TCH traffic > Resource occupancy

� MC370A = Number of FR TCH allocations (FR+EFR+AMR FR)

� MC370B = Number of HR TCH allocations (HR+AMR HR)

� MC703 = Number of TCH allocations for Normal Assignment.

� MC15A = Number of TCH allocations for Internal Directed Retry.

� MC15B = Number of TCH allocations for Handover (intra cell, internal, external).

� TCNACAN indicator is also available as the MAX value of the day on the A9156 RNO tool.

� Some of these indicators are also available for SDCCH:

� SDCCH allocation distribution per TRX through the number of SDCCH allocations

� SDAHCAN = MC390

� SDCCH Assignment/HO distribution through the ratio of SDCCH allocations for Assignment

� SDNACAO = MC148 / MC390




7.4 Resource occupancy indicators


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7.4 Resource occupancy indicatorsTCH resource

� TCH resource occupancy

� TCH traffic in ErlangTCTRE= (MC380A+MC380B) / 3600

� TCH mean holding time (TCH average duration)TCTRMHT= (MC380A+MC380B) / (MC370A+MC370B)

� FR TCH traffic in Erlang TCTRE= MC380A / 3600

� FR TCH mean holding timeTCTRFMHT= MC380A/ MC370A

� HR TCH traffic in Erlang TCTRE= MC380B / 3600

� HR TCH mean holding timeTCTRHMHT= MC380B/ MC370B

B8 (See comments)

New B8

A split of the counters 380a and b

provides information about multiband


� Traffic Load and Traffic Model > TCH traffic > Resource occupancy

� MC380A = Cumulated FR TCH duration per TRX

� MC380B = Cumulated HR TCH duration per TRX

� The following indicators can also be computed:

� TCTRME = Multiband MS TCH traffic in Erlang = MC381 / 3600

� TCTRSE = Single band MS TCH traffic in Erlang = ([MC380A+MC380B] - MC381) / 3600

� MC381 = Cumulated (FR+HR) TCH duration of Multiband mobiles per TRX

In B8, a split of counters (MC380a and MC380b) is added to make the distinction between traffic in different frequency bands: here after the corresponding stored indicators (type 110):

� TCTRFTTGT = Time (in seconds) during which the TCH radio timeslot or dynamic SDCCH/8 timeslot in the GSM frequency band is busy in FR usage = MC380C

� TCTRHTTGT = Time (in seconds) during which the TCH radio timeslot or dynamic SDCCH/8 timeslot in the GSM frequency band is busy in HR usage = MC380D

� TCTRFTTDT = Time (in seconds) during which the TCH radio timeslot or dynamic SDCCH/8 timeslot in the DCS/PCS frequency band is busy in FR usage = MC380E

� TCTRHTTDT = Time (in seconds) during which the TCH radio timeslot or dynamic SDCCH/8 timeslot in the DCS/PCS frequency band is busy in HR usage = MC380F

B8


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7.4 Resource occupancy indicatorsSDCCH / ACH resource

� SDCCH resource occupancy

� SDCCH traffic in Erlang SDTRE= MC400 / 3600

� SDCCH mean holding time (SDCCH average duration)SDTRMHT= MC400 / MC390

� ACH resource occupancy

� ACH traffic in ErlangC750 / 3600

� ACH mean holding time (ACH average duration) QSTRN =C750 / C751


� Traffic Load and Traffic Model > SDCCH traffic > Resource occupancy

� MC400 = Cumulated SDCCH duration per TRX

� MC380 = Number of SDCCH allocations per TRX

� C750 and C751 are 2 counters introduced from B7 in type 18. Both are provided per TTCH (A channel):

� C750 = TIME_A_CHANNEL_BUSY: Time (in seconds) during which the A channel is busy (allocated).

� C751 = NB_A_CHANNEL_ALLOC: Number of allocations of the A channel.




7.5 Traffic model indicators


1.332

7.5 Traffic model indicatorsSDCCH establishment

� SDCCH establishment cause distribution

� Ratio of MT callsTMMTO= MC01 / SDCCH ASSIGN SUCCESS

� Ratio of MO normal and emergency callsTMMTO= MC02H / SDCCH ASSIGN SUCCESS

� Ratio of LU normal (resp. follow-on)TMMOLUR = MC02A (resp. MC02D) / SDCCH ASSIGN SUCCESS

� Ratio of IMSI detachTMMOLUDR= MC02G / SDCCH ASSIGN SUCCESS

� Ratio of Short Message ServiceTMMOSMSR= MC02B / SDCCH ASSIGN SUCCESS

� Ratio of Supplementary ServiceTMMOSSR= MC02C / SDCCH ASSIGN SUCCESS

� Ratio of Call re-establishmentTMMOCRR= MC02E / SDCCH ASSIGN SUCCESS


� Traffic Load and Traffic Model > SDCCH traffic > Traffic model

� SDCCH ASSIGN SUCCESS = Total number of SDCCH establishments for network access = MC01 + MC02

� These indicators allow to get call mix data from the network.


1.333

7.5 Traffic model indicatorsMobiles penetration

� E-GSM mobiles penetration

� Ratio of E-GSM MS access over all MS accesses (except LU)TMMSEGR = MC706 / ([MC01+MC02]-[MC02A+MC02D+MC02G])

� Multiband mobiles penetration

� Ratio of Multiband MS access over all MS accesses (except LU)TMMSMBR = MC850 / ([MC01+MC02]-[MC02A+MC02D+MC02G])

� AMR mobiles penetration

� Ratio of TCH allocation for AMR MS over all TCH allocationsTCTR3CATTO = MC704A+ MC704B / MC703

� TFO calls ratio

� Ratio of successful TFO establishment over all TCH allocations

QSTRCCTR = MC170 / MC703

� Handover per Call

� Number of Handovers (intra cell,internal,external) per Normal Assignment

TMHOCO = (MC717A+MC717B) / MC718

B8

New B8

(See comments)


� Traffic Load and Traffic Model > SDCCH traffic > MS penetration rate


� [MC01+MC02]-[MC02A+MC02D+MC02G] = Total number of initial accesses for call establishment (except location update)

� MC706 = Number of initial accesses for call establishment (except location update) of MS supporting the E-GSM band

� MC850 = Number of initial accesses for call establishment (except location update) of MS supporting two frequency bands (ex: GSM900 and DCS1800)

� MC703 = Total number of TCH allocations (FR+HR) for Normal Assignment

� MC704A = Number of TCH allocations (FR) for Normal Assignment of AMR mobiles only

� MC704B = Number of TCH allocations (HR) for Normal Assignment of AMR mobiles only

� MC704 (Allocation AMR FR+HR) is removed in B8

� MC170 = Number of TCH calls for which a TFO has been successfully established

B8


1.335

7.6 Preemption indicatorsPreemption principle

� Preemption attributes (in Assignment or HO Request):

� pci : preemption capability indication

� indicates if the call can preempt another call (pci=1) or not

� pvi : preemption vulnerability indication

� indicates if the call is preemptable (pvi=1) or not

� priority level: 1=highest priority / 14=lowest priority

� Preemption rules:� A TCH request with pci=1 and priority level=p1 will preempt an on-going

call with pvi=1 and priority level=p2, p2 lower than p1 (whatever pci

value)

� the on-going call with the lowest priority level value shall be elected first

and if several calls have the same lowest p2 value, one of them with pci

bit set to 0 is preferred

� On Preemption capable TCH Request occurrence:

1. The TCH is established through Preemption if a lower priority level on-going call is preemptable. In this case, the on-going call is released and the freed TCH is served to the new request.

2. If no preemption is possible:

� If queuing is possible: the TCH request is queued and either a Directed Retry or a Fast Traffic HO can be performed.

� If queuing is not possible: the TCH request is rejected and an ASSIGNMENT or HANDOVER FAILURE "no radio resource available" message is sent to the MSC.


1.336

7.6 Preemption indicatorsPreemption counters

� MC921A = Number of TCH Requests with the capability to preempt another call with lower priority (pci=1)

� MC921B = Number of preemption capable TCH Requests (pci=1) served with TCH resource (with or without using the preemption feature).

� MC921C = Number of preempted calls

� MC921D = Number of preemption capable TCH Request (pci=1) successfully served in a neighboring cell with the help of the directed retry procedure

� MC921E = Number of preemptable calls successfully established (pvi=1)


� GLOBAL Quality of service INDICATORS> RTCH > Preemption feature


1.337


� Preemption capable TCH Request rejection rate

� TCPPFLCR = (MC921A-MC921B-MC921D) / MC921A

� Ratio of preemption capable TCH Request which led to a successful Directed Retry

� TCPPDSUCR = MC921D / MC921A

� Ratio of preemptable calls established over all calls

� TCPPSUVO = MC921E / (MC718+MC717A+MC717B)


� GLOBAL Quality of service INDICATORS> RTCH > Preemption feature


1.338

Thank you for answering

the self-assessment of the objectives sheet

Introduction to QoS and Traffic Load monitoring / B8Evaluation

� Objective: to be able to interpret:

� Global indicators, in order to assess the general quality of the network

� Detailed indicators, in order to detect / identify / locate the main malfunctions

� Handover indicators, in order to quantify the efficiency and the reason for HO

� Directed retry indicators, in order to quantify the efficiency of a directed retry

� Indicators provided by the new RMS feature to ease radio optimization and fault detection

� Traffic indicators, in order to detect/predict overload and compute adequate cell dimensioning as well as to understand how RTCH resources are used in the network


1.339

Radio Measurement Reporting

ANNEX 1



1.340

� Radio measurement mechanisms

� MS connected (TCH or SDCCH)

� The serving cell gives to the MS the list of the neighboringcells to listen

� Every SACCH, the MS reports to the serving cell: measurement report message

� Received level of 6 best cells (which can change)

� DL level and quality of serving cell


Meast

Report


1.341

� Radio measurement mechanisms

� For each MS connected to the BTS (TCH or SDCCH)


BSC

DL measurements UL+DL measurements

� The UL received level and quality are measured every SACCH

� The Timing advance (TA) is computed

� The UL information is gathered into a measurement report

� this is the message result sent by the BTS to the BSC

Meast

Report

Meast

Result


1.342

� Measurement Result message


L1 Info

L3 Info

Measurement

Report

From the MS

Back

� Basically, the MEASUREMENT RESULT message is composed of:

� L1 info: SACCH Layer 1 header containing MS_TXPWR_CONF and TOA.

� L3 info: MEASUREMENT REPORT from the MS. This message contains the downlink measurements and neighboringcell measurements.

� Uplink measurements performed by the BTS.

� BTS power level used.

� SUB frames correspond to the use of DTX

� if the mobile is in DTX, the rxlevsub or rxqualsub is used to avoid measuring the ts where there is nothing to transmit in order not to false measurements.

� else rxlevfull is used that is to say all TSs are measured.

� MS TXPOWER CONF: what is the actual power emitted by the MS.

� TOA is the timing advance.

� SACCH BFI: bad frame indicator; 2 values 0 or 1; 0 means that the BTS succeeded in decoding the measurement report from the MS.

� How the neighboring cells are coded:

� BCCH1 index in BA list /BSIC1; BCCH2 index in BA list/BSIC2. Why? Because when the mobile is connecting to a new cell, it does not receive LAC/CI (too long) but the list of BCCH frequencies of the neighboring cells (in Band Allocation: BA list). When it reports the radio measurements, it gives the index of the BCCH frequency in the BA list instead of BCCH ARFCN due to the length in case of 1800 frequency coding. Besides the mobile may report a BCCH index / BSIC which does not correspond to a neighboring cell. Of course the BSC will not trigger any handover except if this BCCH index / BSIC couple correspond to a neighboring cell.


1.343

Extended Measurement Reporting

ANNEX 2


(MAFA)


1.344


� The Extended Measurement Reporting is a feature allowing the BSS to request an MS to measure and report up to 21 frequencies of the band that are not included in its BA list

� Such phase 2+ mobiles must support the optional MAFA feature (Mobile Assisted Frequency Allocation)


1.345

MS BTS BSC MSC

TCH ASSIGNMENT PHASE (OC or TC)< -----------------------------------

ASSIGNMENT REQUEST

< --------------------------------------------------------

PHYSICAL CONTEXT REQUEST

-------------------------------------------------------- >

PHYSICAL CONTEXT CONFIRM

< --------------------------------------------------------

CHANNEL ACTIVATION (TCH)

(EMO included)

-------------------------------------------------------- >

CHANNEL ACTIVATION ACKNOWLEDGE

.

.

TCH establishment.

--------TCH---------> .

ASSIGNT COMPLETE ------------------------------------------------------- >

ASSIGNMENT COMPLETE ----------------------------------- >

<------SACCH-------- ASSIGNMENT COMPLETE

--------SACCH------>

<------SACCH--------

--------SACCH------>

<-------SACCH--------

EMO

(MAFA freq. List)

--------SACCH------>

EMR

(MAFA freq. RxLev)

<------SACCH--------

--------SACCH------>

� Extended Measurement Reporting mechanisms


� The Extended Measurement Order includes the MAFA frequencies the MS is asked to measure

� EMO sent once to the MS on SACCH after TCH seizure

� Extended Measurement Results include the average signal level measured on each MAFA frequency over one SACCH mf duration

� EMR received once per call on SACCH

Back

� When the BTS receives a CHANNEL ACTIVATION with the Extended Measurement Order (EMO) included, it shall send this information on the SACCH to the corresponding mobile only once.

� When the BTS has to send this information, it shall replace the sending of system information 5, 5bis, 5ter or 6 by this information. At the next SACCH multi-frame, the BTS shall resume the sending of this system information by the replaced one.

� The EMO shall be sent after 2 complete sets of SYS_INFO5 and 6, i.e. after the 2nd SYSINFO 6 after the reception of SABM. This guarantees the MS has received a complete set.

� Then, the BTS normally receives from the MS an EXTENDED MEASUREMENT RESULT with the level of the frequencies to monitor. The BTS shall make the correlation between these levels and the frequencies contained in the latest EMO information, after having decoded them, according to the order of the ARFCN. The ‘EXTENDED_MEASUREMENT_RESULT’ is NOT forwarded to the BSC, instead a ‘MEASUREMENT_RESULT’ with indication ‘no_MS_results’ is sent to the BSC.

� In particular, the BTS shall identify the level of the BCCH frequency of the serving cell (which shall always be part of the frequencies to monitor) and apply it as the RXLEV_DL in the Radio Measurement Statistics. The other frequencies will be considered in the same way as BCCH frequency of neighboring cells: they will be linked to the neighboring level and C/I statistics.


1.346

ANNEX 3

GSM BSS Protocol Stacks



1.347

� Signaling Links

A-Interface MT-Link signaling #7 System with SCCPMSC BSC

BSC BTSAbis Interface RSL with LAPD Protocol

BTS MSAir-Interface (CCCH/SACCH/FACCH) with LAPDm Protocol

BSC OMC-ROML Link with X25 connection LAPB Protocol



1.348

The reference Model

7 Application

6 Presentation

4 Transport

5 Session

2 Data Link

3 Network

1 Physical

User of Transport Service

Transport ServiceNetworkService



1.349

� Layer 1

� Physical; Responsible for the transparent transmission of information across the physical medium (HDB3, PCM, AMI)

� Layer 2

� Data Link; Responsible for providing a reliable transfer between the terminal and the network (#7, LAPD,etc.)

� Layer 3

� Network; responsible for setting up and maintaining the connection across a network (CM, MM, RR, Message routing, etc.)



1.350

� Layer 4

� Transport; responsible for the control of quality of service (Layer of information)

� Layer 5

� Session; Handles the coordination between the user processes (Set up transfer of information)

� Layer 6

� Presentation; responsible for ensuring that the information is presented to the eventual user in a meaningful way (Type format. Ex. ASCII)

� Layer 7

� Application; provides user interface to lower levels

(Operating System)



1.351

BTSPSTNISDN

Air Intfc Abis Intfc A Intfc B .. F Intfc

MS BSC MSC

CM

MM

RR

LAPDm

digit

radio

RR BSSAP

LAPDm LAPD

digit

radio64 kb/s 64 kb/s 64 kb/s 64 kb/s

LAPD

RR

BTSM

BSSAP

CM

MM

BSSAP

SCCP

MTP

SCCP

MTPLAYER 2

LAYER 1

LAYER 3


� BSS protocol stacks


1.352


SSCS

SSTM 3

SSTM 2

SSCS

SSTM 3

SSTM 2

SSGT

MAP

SSGT

MAP

SSCS

SSTM 3

SSTM 2

PCM TS

DTAP

SSCS

SSTM 3

SSTM 2

PCM TS

DTAP

LAPDLAPDm LAPD

SS (SMS)SS (SMS)

BSSMAP

MM

CC

BSSMAPRR

RR

RR' BTSMBTSM

LAPDm

(SMS)

SSCC

MM

(Relay)

MS BTS BSC MSC / VLR NSS(ex. : HLR)

Um A bis A (D)

1

2

3

(Relay

64 kbit/s

or PCM TS64 kbit/s

or PCM TSPCM TS PCM TS

PhycalLayer

� BSS protocol stacks (detailed)

PhycalLayer


1.353

� Signaling on the A Interface

� Uses #7 with Signaling Connection Control Part (SCCP) with a new Application Base Station Application Part (BSSAP). BSSAP is divided into Direct Transfer Application Part (DTAP) and Base Station Subsystem Management Application Part (BSSMAP)

DTAP

BSSMAP

SCCP

MTP 1-3

User Data

Layer 1-3

BSSAP



1.354

� BSSMAP

� Contains the messages, which are exchanged between the BSC and the

MSC and which are evaluated from the BSC.

� In fact all the messages, which are exchanged as RR (Radio Resource

Management Services between the MSC, BSC and MS). Also control Information concerning the MSC and BSC.

� Example: Paging, HND_CMD, Reset

� DTAP

� Messages which are exchanged between an NSS and an MS

transparent. In this case, the BSC transfers the messages without

evaluation transparent. Mainly Messages from Mobility Management

(MM) and Call control (CC)



1.355

� Relationship between DTAP, CC, MM, BSSMAP, RR

MSBSS MSC

Call Control (CC) DTAP

Radio Resource (RR)BSSMAP


Back


1.356

ANNEX 4

B8 Improvements summary

B8 Improvements summaryB8


1.357

� Location Services (LCS)

� SDDCH Dynamic allocation

� Counters Improvement

� Inter PLMN HO

� 3G to 2G HO (and 2G to 2G only)

� Dual band HO (New type: 32)

� LapD congestion counter

� QOS Followup

� TCH assignment failure BSS PB now detailed

� HO Attempts for Fast Traffic added in type 110

� AMR counters added in type 110

� MS penetration (per speech version and channel type) was type 1 counters now available in type 110

� HO Causes: type 26 extended from 1 to 40 cells

� Directed retry: type 29 becomes a standard (for PMC)

B8 Improvements summaryB8

qos_b8

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