2g training optimization

1 © Nokia Siemens Networks

BSS Optimisation WorkshopDenpasar BaliOct 21-25, 2013

NSN – TSEL


Idle Parameter Optimization

Power Control Parameter

Handover Control parameter

Radio Resource Administration

Radio resource Management

KPI case

Measurement processing


Radio Resource Administration


TDMA frame= 8 timeslots( 0.577ms * 8 = 4.615 ms)

01

34

5

76

01

23

45

76

01

23

45

200 kHz

Physical channel e.g. allocated to onesubscriber with FR voiceand no frequency hopping

frequency

time

TDMA frame2

2 2 2

Basic TDMA Structure


Base StationSubsystem

Logical Channelsfor transport of specific content

Physical Channelstransport medium

MS

mapping

Physical channel parametersARFCNTime slot numberFrequency hopping algorithm

GSM Channel Organization


SCH

FCCH

PCH

BCCH

AGCH

RACH

SDCCH

SACCH

FACCH

Stand alone Dedicated Control Channel

Frequency Correction Channel

Synchronisation Channel

Broadcast Control Channel

Paging Channel

Slow Associated Control Channel

Fast Associated Control Channel

Paging Channel

Random Access Channel

Access Grant Channel

BCH

CCCH

DCCH

TCH

DL

DL

DL

UL

CommonChannels

DedicatedChannels

UL/DL

UL/DL

CBCH Cell Broadcast Channel

Logical Channels

FR/HR Full rate / Halft rate TCH

EFR Enhanced Full rate TCH

AMR FR/HR Adaptive multirate TCH (FR/HR)


f s ff s f s

Downlink51 TDMA frames = 235 ms

-

Uplink

BCCH CCCH

f s f s

CCCH CCCH

r r f r r rr r r r fr r r r r rr r r r fr r r r rr f r r

1 51

CCCH CCCH CCCH CCCH CCCH CCCH

r rr r rr r r r r r r rr r r r r rr rr r r

f = FCCH, s = SCH, r = RACH TDMA frame- = dummy burst

51 TDMA frames = 235 ms

1 51

Signalling Channel Mapping(BCCH +CCCH/9)


f s ff s f s

Downlink51 TDMA frames = 235 ms

-

Uplink

BCCH CCCH

f s f s

CCCH CCCHSDCCH 0

SDCCH 1SDCCH 2

SDCCH 3SACCH

0/2 SACCH1/3

r r f r r rr r r r fr r r r r rr r r r fr r r r rr f r r

1 51

SACCH2/0 SACCH

3/1

SDCCH 0SDCCH 1SDCCH 3

SDCCH 2

f = FCCH, s = SCH, r = RACH TDMA frame- = dummy burst


1 51

Signalling Channel Mapping(BCCH + SDCCH/4 + SACCH/C4)


...


1 26

t t tt t t t ft tt t t tt t t tt ft t t ttts i

Full Rate Traffic Channel Configuration (UL & DL)

Half Rate Traffic Channel Configuration (UL & DL)


1 26

t

T T

t t

T

tf

t t

T T T T

t t

T

t

Tf

T

t

T

tt

T

s

S

t = full rate TCH, s = SACCH/T, i = idle TDMA frame

t = half rate TCH, s = SACCH/T (first user)T = half rate TCH, S = SACCH/T (second user) TDMA frame

Traffic Channel Mapping


f

f

i = idle TDMA frame

f


iii

iii

SDCCH 0SDCCH 1

SDCCH 2SDCCH 3

SDCCH 4SDCCH 5

SDCCH 6SDCCH 7

SDCCH 1SDCCH 2

SDCCH 3SDCCH 4

SDCCH 5SDCCH 6

SDCCH 7SDCCH 0

Downlink

Uplink

SACCH0/4 SACCH

1/5

SACCH2/6 SACCH

3/7

SACCH6/2 SACCH

7/3

SACCH4/0SACCH

5/1


1 51

1 51

Signalling Channel Mapping(SDCCH/8 +SACCH/C4)


Signalling Channel Mapping

New improved CCCH features in RG10•BSS20738 CS Paging Coordination in NMO II•BSS21538 Extended CCCH

– Extended CCCH can be allocated to timeslot 2,4,6

•BSS101411 Extended BCCH– For example Uncombined BCCH


Channel configuration defined by parameter channelType

TCHF (0) = full rate traffic channelTCHH (1) = half rate traffic channelTCHD (2) = dual rate traffic channelSDCCH (3) = standalone (SDCCH/8)MBCCH (4) = broadcast control channelMBCCHC (5) = BCCH + SDCCH/4MBCCB (7) = BCCH + SDCCH/3 with CBCHSDCCB (8) = SDCCH/7 with CBCHNOTUSED (9) = timeslot has no radio definition or Abis allocationERACH (10) = random access channel of extended areaEGTCH (14) = EGPRS packed data traffic channel for extended areaLRTCH (15) = long reach traffic channel

Channel MappingParameter Setting

Note: • Some values not allowed in certain tsl (e.g. TSL0 can’t have value 8)• PBCCH is not supported in S13 and onwards

MO Class TR/RTSLParameter channelxType (CHx) where x = 0…7


Mobile terminating call -> MSC performs paging

MS identifies paging message with the IMSI/TMSIMS listens to own paging group only

SEG-BTS parameters

MSC parameters

Repaging Interval (INT) 0.5s…10s Time between consecutive pagingattempts

Repaging Attempts (AT) 0…5 Number of paging repetitions

Buffering

BTS stores up to 8 paging messages of the MSC in page group bufferBTS sends paging messages to MS according noOfMultiframesBetweenPaging

Paging Channel (PCH) Parameters

MO Class

Abbreviated Name

Range And Step

Description Default value

BSC - MML Name

BTS noOfMFramesBetweenPaging

2...9, step 1

Defines the number of multiframes between two transmissions of the same paging message to the MSs of the same paging group.

4 MFR


Mobile sends channel requests to BTS separated by random time intervals in case of no answer!

Parameters

Random time interval between consecutive retransmissions

t = S + random [0,.. numberOfSlotsSpreadTrans – 1] RACH slots

S depends on numberOfSlotsSpreadTranssignalling channel mapping (CCCH + SDCCH combined or not in one multi frame)

numberOfSlotsSpreadTrans = 10

signalling channel mapping = not combined S = 58

Therefore t = 58..to..67 RACH slotstime channel requests

RACH Parameters

MO Class

Abbreviated Name

Range And Step Description Default value

BSC - MML Name

BTS maxNumberRetransmission

1,2,4,7 Maximum number of retransmissions on the RACH that the MS can perform.

4 RET

BTS nbrOfSlotsSpreadTrans

MML Range: 3..12, 14, 16, 20, 25, 32, 50

The number of TDMA frames over which retransmission is spread on the RACH (random access channel)

10 SLO


Network gives the MS dedicated resources

Downlink CCCH blocks

• PCH can be used for AGCH messages• AGCH cannot be used for PCH messages

Reservation of CCCH blocks for AGCH

noOfBlocksForAccessGrant (AG) 0..7 possible number, if CCCH and SDCCH are not combined1..7 possible number, if CBCH is used in non combined configuration0..2 possible number, if CCCH and SDCCH are combined

Preference of AGCH messages on PCH

noOfBlocksForAccessGrant 0 PCH can be used only, if no paging messages have to be send

= 0 AGCH messages have higher priority than PCH ones

Number of paging groups

N = (number of CCCH blocks – noOfBlocksForAccessGrant) * noOfMultiframesBetweenPaging

AGCH Parameters


Combined CCCH / SDCCH configuration

noOfBlocksForAccessGrant = 1 2 CCCH blocks for PCH

3 MSs paged per paging message 3 pages per block2 blocks per multi frame 3 * 2 = 6 pages per multiframe

Number of pages per hour 3600 s / 0.235 s * 6 = 91915

Avg of 2 pages required per MS 91915 / 2 = 45957 MSs per hour

BTS 3 MS

Paging_Request

BTS 3 MS

Paging_Request

Paging CapacityExample


Cell with 325 subscribers1 call per subscriber once in a hour1 location update (LU) per subscriber once in 2 hours

Duration of call assignment = 4 s 4 s / 3600 s = 1.11 mErl on SDCCH per subscriber325 subscribers 325 * 1.11 mErl = 0.3607 Erl on SDCCH

Reservation time for LU = 5s 5 s / 7200 s = 0.69 mErl on SDCCH per subscriber325 subscribers 0.2242 Erl on SDCCH

Total SDCCH traffic 0.3607 Erl + 0.2242 Erl = 0.5849 ErlBlocking probability = 1% 4 SDCCHs required SDCCH combined with

CCCH can be used (MBCCHC)

SDCCH Signalling CapacityExample with call Establishment & Location Update


Same cell with 325 subscribersAdditional SMS traffic of 1 mErl per subscriber

325 subscribers 325 * 1 mErl = 0.325 Erl on SDCCH

Total SDCCH traffic 0.5849 + 0.325 Erl = 0.9099 ErlBlocking probability = 1% 5 SDCCHs required not combined with

CCCH (MBCCH)

SDCCH Signalling CapacityExample including SMS


Base Station Identity Code BSIC = Network Colour Code NCC + Base Station Colour Code BCC

bsIdentityCode Setting of BSIC

NCC 0..7, distinguishes between PLMNsBCC 0..7, distinguishes between clusters

BSIC + frequency channel unique identity of adjacent cell

f1f2f3

f1

f1

bcc = 1

bcc = 2

bcc = 3

Base Station Identity Code


200 kHz

890 915 935 960

1 2 3 4 124123 1 2 3 4 124123

duplex distance

Absolute radio frequency carrier number ARFCN

uplink direction downlink direction

Example: GSM 900

Defining Frequency carrier number


Frequency to be used by TRX (must be unique within a BTS)

initialFrequency (FREQ) 1…1023 Setting of ARFCNs

GSM 800: 128 .. 251 GSM 900: 1..124 and 975..1023, 0 GSM 1800: 512..885 GSM 1900: 512..810

f1f2

f3f4

f5f6

f7

f1f2

f3f4

f5f6

f7

f1f2

f3f4

f5f6

f7

Frequency Reuse


Frequency

Time

F1

F2

F3

Call is transmitted through several frequencies to• average the interference (interference diversity)• minimise the impact of fading (frequency diversity)

Frequency hopping techniques

hoppingMode (HOP) BB,RF,NBB = base band hopping (1)RF = RF hopping (2)N = no frequency hopping at all (0)

Principle of Frequency Hopping


Baseband Hopping

TRX 1

TRX 2

TRX 3

0 1 72 Timeslot

TRX 4

BCCH

f 1

f 2

f 3

f 4

HSN1 (BB hopping group 1 and RF hopping)Timeslot 0 hops over TRXs 2-4 onlyBCCH does not hop

HSN2 (BB hopping group 2)Timeslots 1-7 hop over all TRXs

TRXs do not hopPhysical channels moved from one TRX to another

Hopping sequencehoppingSequenceNumber (HSN) 0..63

0 = cyclic hopping1..63 = pseudorandom hopping

Base Band Hopping


RF HoppingStandard technique

TRX 1

TRX 2

TRX 3

0 1 72 Timeslot

TRX 4

BCCH f1 – no hopping

f2,f3..fn – hopping accordingmobile allocation list One hopping sequencenumber only

All TRXs hop except TRX1 (provides BCCH)Up to 63 frequencies available defined by mobile allocation list -> better hopping gain

mobileAllocationList Setting of ARFCN values usedMobileAllocation (MAL) 0,1...2000 0 = BTS detached from any list

1..2000 = indicates list which shall be used


Standard technique

9 hopping hopping frequencies MAI = 0..8But 3 frequencies available for every TRX only

Freeform hopping

For every sector samemobile allocation listhopping sequence numberframe number (frame synchronization)

For every sector differentstarting points for hopping sequencepossible by mobile allocation index offset

maioOffset (MO) 0..62

setting of MAIO

9 hopping hopping frequencies MAI = 0..89 frequencies available for every TRX

RF HoppingFreeform Hopping

MAIO Offset MAI

TRX-1 (BCCH) -

TRX-2 0

TRX-3 1

TRX-4 2

TRX-5 (BCCH) -

TRX-6 3

TRX-7 4

TRX-8 5

TRX-9 (BCCH) -

TRX-10 6

TRX-11 7

TRX-12 8

Sector-3 6

Sector-1 0

Sector-2 3


Freeform hopping

• Not adequate for MA list with consecutive ARFCN values• Avoids co-channel interference but not adjacent channel interference

Flexible MAIO management

MAIO increases with constant step size from one TRX to the next one

maioStep (MS) 1..62

maioOffset = 0, 6, 12 for sector 1, 2, 3maioStep = 218 frequencies required (2 * number of hopping TRXs)

RF HoppingFlexible MAIO Management

MAIO Offset

MAIO Step MAI

TRX-1 (BCCH) -

TRX-2 0

TRX-3 2

TRX-4 4

TRX-5 (BCCH) -

TRX-6 6

TRX-7 8

TRX-8 10

TRX-9 (BCCH) -

TRX-10 12

TRX-11 14

TRX-12 16

Sector-3 2

0

6

12

Sector-1 2

Sector-2 2


BCCH

Band allocation:

MA listConsecutive ARFCN

Only BCCH frequency planning required

Flexible MAIO managementMAIO Offset + MAIO Step

BCCH

Band allocation:

MA listNon-adjacent ARFCN

Freeform hoppingMAIO Offset

MA list and BCCH frequency planning required

RF Hopping (Tight Frequency Reuse)


Changing Frequency Plan

BSIC / TSCFrequenciesFrequency hopping settingIntelligent underlay overlay TRX settings

• Plan downloaded to BSC/BTSs via MML or GUI• File-based plan provisioning• Immediate Plan activation method


Idle Mode Operation


• When the MS is switched ON• When there is no dedicated connection

When?

• To camp on the best suitable cell

Why?

• For MS to receive system info from the NW on DL• For MS to be able to initiate a call whenever needed• For the NW to be able to locate the MS when there is a MT call/SMS

Why to camp on a specific cell?

• PLMN selection• Cell selection & re-selection• Location updates

Idle Mode Tasks

Idle Mode OperationI

MS switched ON

Search RF channels to find BCCH carrier

Check that the PLMN & cell is allowed

MS camps on the best

suitable cell

See slide 10 for detail


Value

LAI (locationAreaId)

• NCC (Network Colour Code) 0 … 7• BCC (BTS Colour Code) 0 … 7

BSIC (bsIdentityCode)

CI (cell-ID 0 … 65535

Parameter

TSC (trainingSequenceCode) 0 … 7

• MCC (Mobile Country Code) 0 … 999• MNC (Mobile Network Code) 0 … 99,

0… 999 (optional 3-digit MNC)• LAC (Location Area Code) 1 … 65533

CGI (Cell Global Identity) MCC + MNC + LAC + CI

ID’s and ID Codes


Campednormally

(adopted from TS 43.022 V5.1.0 chap. 6)

Connectedmode

Normal cell selection

Stored listcell selection

Choose cell Normal

cell re-selection

go here whenever anew PLMN is selected

BA list storedfor PLMN

no BA list storedfor PLMN 1

no suitable cell found

suitable cell foundsuitable cell found

trigger

Suitable cellre-selected

no suitablecell found

suitable cell found

leaveidle

mode

return to idlemode

no suitable cell found

no suitablecell found• IMSI unknown

• Illegal MS• PLMN not allowed

2

2

States and State Transition for Cell Selection


Any cellselection

Camped on

any cell

Choose cell

cell foundno suitable

cell found

suitable cell found

leaveidle

mode

return to idlemode

Connected mode (emergency call

only)

Anycell re-

selection

trigger

cellre-selected

no suitablecell found

go here when no SIM in MS SIM inserted in MS 1

2

cell foundon selected

PLMN

(adopted from TS 43.022 V5.1.0 chap. 6)

States and State Transition for Cell Selection


Normal Cell SelectionSearch all the RF channels, take samples during

3-5 s and calculate averages. And put them in ascending order with respect to signal level.

Then tune to the strongest RF channel.

Search for the frequency correction burst in that carrier in order to verify if it is a BCCH carrier

Camp on the cell

Try to synchronize to the carrier and read the BCCH data

Is it a BCCH carrier?

Is it a correct PLMN ?

Is the cell barred?

Is C1>0

Tune to the next highest RF channel which is not

tried before

No

No

NoNo

Yes

Yes

Yes

Yes


I am outside

I am inside, but have not enough

power

C1 = A – max(B,0)= RLA_C – RXLEV_ACCESS_MIN – max(MS_TXPWR_MAX_CCH – P , 0)

RLA_C = avg received RxLev on BCCHP = MS max output power

max(B,0)

0..63 0..31

Pathloss Criterion C1 for Cell Selection and Reselection


Cell1LAC1

C1 ( Cell1) C1 (Cell2)

A B C

A= 4 dBB= 6 dBC= 8 dB

Cell2LAC2

In case the neighbouring cells belong to different Location Area, a hysteresis is applied with C1 criteria• minimizing ping-pong cell reselections• cellReselectHysteresis (HYS)(BTS) (0…14 dB)

Cell Selection with C1


C1 + CELL_RESELECT_OFFSET – (TEMPORARY OFFSET * H(PENALTY_TIME - T))for PENALTY_TIME 640 s

< C1 if temporary offset big for PENALTY_TIME = 640 sC2 =

serving cell:• C2:

List of 6 strongest carriers:• C2:• C2: • C2:• C2: • C2: • C2:

0 .. 126 dBstep size: 2 dB

0, 10, 20, 30, 40, 50, 60, dB

20 .. 640 sstep size: 20 s

PENALTY_TIME

TEMPORARY OFFSET

CELL_RESELECT_OFFSET

C1

C2

T

new candidate= formerly non-

serving cell

CELL_RESELECT_OFFSET

C1

C2

T

new candidate= former serving cell

no TEMPORARY OFFSET

Pathloss Criterion C2


cell 1

cell 2

cell 3

C2

time5 seconds

cellreselection

5 seconds

CELL_RESELECT_HYSTERESIS (HYS)

LAC = A LAC = B

cell reselection &location update

Cell Reselection Based on Pathloss Criterion C2


Cell "A" Cell "B" Cell "C" Cell "D"

cellReselectOffset 0 dB 20 dB 0 dB 0 dB

temporaryOffset 0 dB 30 dB 0 dB 30 dB

penaltyTime 20 s 20 s 20 s 40 s

Micro 900 "D"Macro 1800 "B"

Macro 900 "A"

Macro 900 "C"Road

Parameters

=30 Cell "A" (Serving Cell)=25 Cell "B"=5 Cell "C"=50 Cell "D"

=30 + 0 (H(x)=0, serving cell) Cell "A"=25 + 20 - 30*H(20 - T) Cell "B"=5 + 0 - 0*H(20 - T) Cell "C"=50 + 0 - 30*H(40 - T) Cell "D"

C1

C2 = C1 + cellReselectOffset - temporaryOffset*H(penaltyTime-T)

C2

Time T: (0 - 19 s)C2 =30 Cell "A"C2 =15 Cell "B"C2 =5 Cell "C"C2 =20 Cell "D"

Time T: (20 - 39 s)C2 =30 Cell "A"C2 =45 Cell "B"C2 =5 Cell "C"C2 =20 Cell "D"

Time T: (> 40 s)C2 =30 Cell "A"C2 =45 Cell "B"C2 =5 Cell "C"C2 =50 Cell "D"

Cell Reselection Based on Pathloss Criterion C2


When shall I select a new cell?

Pathloss Criterion C1 C1 0 for a period of 5 s

Pathloss Criterion C2 • neighbour‘s C2 value >

current cell‘s C2 value (same LA)• neighbour‘s C2 value >

current cell‘s C2 value + HYS (new LA)

for a period of 5 s.Downlink Signalling Failure

DSC 0

RACH Failure MAX RETRANS + 1 times

Authentication Failure notification by upper layers

Cell has been barredCELL_BAR_ACCESS & CELL_BAR_QUALIFY

Cell Reselection Events


BTS

BCCH (...,BS_PA_MFRMS,...)

MS

Downlink radio link failure detected!

DSCinit := roundBS_PA_MFRMS

90

paging message successfully

decoded?

DSC 0

DSC := min (DSC+1, DSCinit) DSC := DSC - 4

yes no

no

yesCell

UpdateDSC = Downlink Signalling failure Counter

2..9 multi-frame periods

DSC := DSCinit

DL Signalling Failure


Location Update Procedure

BSS MSC VLR HLR

REQUEST SUBSCRIBER INFO

ALL OK - HLR UPDATE

MS

LOCATION UPDATE REQUEST

SEND SUBSCRIBER ID

REQUEST SUBSCRIBER ID

SEND SUBSCRIBER INFO

AUTHENTICATION

AUTHENTICATION RESPONSE


Paging LocUp

# of cells in Loc. area

signallingtraffic

optimum numberof cells in Loc. area

function of user density,cell size, call arrival rate ...function of

user mobility

Trade-off between Location Update and Paging Traffic


Location Updates

• MS location & status flag => MSC / VLR• Mobile Station switched ON mode

– IMSI Attach / Detach– Same Location Area => No Location Update– Different Location Area => Location Update

• Change of the Location Area– Location Area under the same MSC / VLR– Location Area under another MSC / VLR => HLR will be updated

• Service is rejected (MS unknown in VLR)• Time-Periodic LU (MS -> MSC/VLR)

MO Class

Abbreviated Name

Range And Step

Description Default value

BSC - MML Name

BTS allowIMSIAttachDetach

Yes/No Defines whether IMSI attach/detach is used in the cell. Yes ATT

BTS timerPeriodicUpdateMs

0...25.5 h, step 0.1 h

Defines the interval between periodic MS location updates. The value 0 means that the periodic location update is not used.

0.5 h PER


IDLE MODE OPERATION Idle Mode Controls

Parameter Value

Access Parameters

notAllowedAccessClasses 0 ... 9, 11 ... 15emergencyCallRestricted Yes/No

msTxPwrMaxCCH 13 ... 43 (dBm)rxLevAccessMin -110 ... -47 (dBm)

msMaxDistanceInCallSetup 0 ... 255radiusExtension 0 ... 67 (Km)

cellBarred Yes/Noplmn-permitted 0 ... 7cellReselectHysteresis 0 ... 14 (dB)

Mobility Parameters

cellReselectOffset (REO) 0 ... 126 (dB)

cell reselection parameter index (PI) (N/Y)


IDLE MODE OPERATION Idle Mode Controls definitions • RxLevAccessmin : With this parameter you define the minimum power level an MS has to receive before it is allowed to access the cell. • MsTxPwrMaxCCH : With this parameter you define the maximum transmission power an MS may use when accessing a CCH in the cell.• notAllowedAccessClasses With this parameter you define the MS access classes that are not allowed to access a cell.• Emergency Call Restricted With this parameter you define if an emergency call in the cell is allowed to all MSs or only to the MSs which belong to

one of the classes between 11 to 15. Value ’Y’ means the latter case.• MsMaxDistancein CallSetup With this parameter you define the maximum distance between the BTS and the MS in call setup. The maximum distance

is expressed as an access delay. Within the range of 0...62, one step correlates to a distance of 550 meters. If the access delay of the channel request message exceeds the given maximum, the call attempt is rejected. When the parameter is given a value from 63 to 255, call attempts are never rejected

• radiusExtention With this parameter you define the radius extension of an extended cell


Radio Resource management


Channel request (RACH)MS NETWORK

Immediate assignmentImmediate assignment (AGCH)

Service request (SDCCH)

Service request

Authentication request (SDCCH)

Authentication response (SDCCH) Authentication

Ciphering mode command (SDCCH)

Ciphering mode complete (SDCCH) Ciphering mode setting

Setup (SDCCH)

Call initiationCall proceeding (SDCCH)

Assignment command (SDCCH)

Assignment complete (FACCH) Assignment of traffic channel

Alert (FACCH)

Call confirmation

Connect (FACCH)

Connect acknowledged (FACCH) Call accepted

Signalling (Mobile Originating Call)

Idle parameter

Dedicated parameter


Page request (PCH)MS NETWORK

Immediate assignmentChannel request (RACH)

Page response (SDCCH)

Service request

Authentication request (SDCCH)

Authentication response (SDCCH) Authentication

Ciphering mode command (SDCCH)

Ciphering mode complete (SDCCH) Ciphering mode setting

Setup (SDCCH)

Call initiationCall confirmation (SDCCH)

Assignment command (SDCCH)

Assignment complete (FACCH) Assignment of traffic channel

Alert (FACCH)

Call confirmation

Connect (FACCH)

Connect acknowledged (FACCH) Call accepted

Immediate assignment (AGCH)

Signalling (Mobile Terminating Call)

Idle parameter

Dedicated parameter


DisconnectMS NETWORK

Call clearingRelease

Channel release

Release

Release complete

DisconnectMS NETWORK

Call clearingRelease

Channel release

Release

Release complete

Network initiated

MS initiated

Signalling (Call Release)


MS capabilities

Channel rate : full, half, dual, multi rateSpeech codecs : normal FR, normal HR, EFR, AMR FR, AMR HR, doubleHR(OSC)

MSC demands

A interface circuit allocated for call

BTS demands

Speech codec capabilitiesTCH configurationCurrent resourcesHomogeneous use of TRXs and radio time slotsLarge free groups of radio time slots for high loaded HSCSD BTS

Standard TCH Allocation (General Criteria)


TCH Allocation 2 TRX=16 channels

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

12:0

0:00

AM

2:00

:00

AM

4:00

:00

AM

6:00

:00

AM

8:00

:00

AM

10:0

0:00

AM

12:0

0:00

PM

2:00

:00

PM

4:00

:00

PM

6:00

:00

PM

8:00

:00

PM

10:0

0:00

PM

RTSL

SDCCH

BCCH

PEAK_PERMANENT_GPRS_CH

AVE_GPRS_CHANNELS

AVE_TCH_BUSY_FULL

0 1 2 3 4 5 6 7TRX1 BCCH SDCCH SDCCH V/D V/D V/D V/D V/DTRX2 SDCCH SDCCH V/D V/D V/D V/D D D

TIM

E

AV

E_S

DC

CH

(SD

CC

H/8

)

AV

E_B

US

Y_S

DC

CH

PE

AK

_BU

SY

_SD

CC

H

AV

E_A

VA

IL_F

ULL

_TC

H

AV

E_T

CH

_BU

SY

_FU

LL

PE

AK

_BU

SY

_TC

H

TCH

_PE

AK

_BU

SY

_FU

LL

TCH

_PE

AK

_BU

SY

_HA

LF

SD

CC

H_C

ON

G_T

IME

(sec

)

TCH

_FR

_RA

DIO

_CO

NG

ES

TIO

N_T

IME

(sec

)

TCH

_HR

_RA

DIO

_CO

NG

ES

TIO

N_T

IME

(sec

)

AV

E_G

PR

S_C

HA

NN

ELS

PE

AK

_GP

RS

_CH

AN

NE

LS

PE

AK

_PE

RM

AN

EN

T_G

PR

S_C

H

12:00:00 AM 32 5.0 18 6.3 4.0 9 9 0 0 8.48 0 4.7 8 2

1:00:00 AM 32 3.1 13 6.8 3.4 9 9 0 0 1.41 0 4.2 9 2

2:00:00 AM 32 1.7 12 5.2 2.9 7 7 0 0 0 0 5.8 9 23:00:00 AM 32 1.5 12 6.2 1.4 7 7 0 0 0 0 4.8 9 24:00:00 AM 32 1.6 10 8.0 1.7 5 5 0 0 0 0 3.0 9 25:00:00 AM 32 8.8 32 5.7 0.8 6 6 0 559 0 0 5.3 9 26:00:00 AM 32 5.2 18 4.3 1.1 6 6 0 0 0 0 6.7 9 27:00:00 AM 32 6.5 23 8.5 2.6 8 8 0 0 0 0 2.5 6 28:00:00 AM 32 4.8 20 6.6 2.2 7 7 0 0 0 0 4.4 9 29:00:00 AM 32 4.3 20 6.8 2.4 8 8 0 0 0 0 4.3 9 2

10:00:00 AM 32 5.2 32 7.5 2.6 9 9 0 2 0.21 0 3.5 9 211:00:00 AM 32 5.9 18 6.3 2.9 9 9 0 0 8.98 0 4.7 9 212:00:00 PM 32 5.9 19 6.8 3.9 9 9 0 0 13.52 0 4.2 8 2

1:00:00 PM 32 7.3 24 6.4 3.4 9 9 0 0 8.96 0 4.6 9 22:00:00 PM 32 6.8 30 6.2 3.9 9 9 0 0 44.05 0 4.8 8 23:00:00 PM 32 7.1 21 6.7 4.7 9 9 0 0 64.18 0 4.3 9 24:00:00 PM 32 7.7 23 6.6 3.9 9 9 0 0 25.61 0 4.4 8 25:00:00 PM 32 8.5 23 6.7 3.9 9 9 0 0 34.51 0 4.3 9 26:00:00 PM 32 10.7 27 8.3 5.9 9 9 0 0 320.58 0 2.7 7 27:00:00 PM 32 11.1 28 8.4 5.6 9 9 0 0 217.77 0 2.6 9 28:00:00 PM 32 10.4 30 7.8 5.5 9 9 0 0 284.15 0 3.2 8 29:00:00 PM 32 9.3 26 7.5 5.3 9 9 0 0 217.65 0 3.5 8 2

10:00:00 PM 32 8.3 22 7.5 5.2 9 9 0 0 185.36 0 3.5 9 211:00:00 PM 32 5.8 21 6.8 4.6 9 9 0 0 89.61 0 4.2 9 2

How can be optimized?


Channel allocation ( For each TS)

Each TRX – have its own Quality both DL and UL and TRX with bad quality (UL and DL) will result bad KPI on respective TRX

Placing each Time Slot (BCCH, SDCCH, TCH and PDTCH) properly will result good KPI (SDSR, DCR, HOSR TBF Completion rate)

Shitting SDCCH, BCCH can improve SDSR and DCR


Measurement of uplink receive level on idle channels = uplink interference

Averaging over interferenceAveragingProcessAverPeriod (AP) = 1..32 SACCH periods

Classification into interference bands based on interferenceAveragingProcess (BO1..BO4) = -110..-47 dBm

BSC tries to allocate TCH from best interference band (can be requested by MSC) If not available, BSC tries to take TCH from next band

0 71 2 3 4 5 6

rxLevUL = -75 dBm BO5 –47 (fixed)

BO0 –110 (fixed)

BO4 -90BO3 -95

BO1 -105BO2 -100

Standard TCH Allocation(Interference Bands)


Priority for TCH from BCCH TRX

BCCH transmitted permanently -> no additional interference in networkPlanned to be least interfered channels

Priority for TCH from other TRX

BCCH TRX does not hop in case of RF hopping -> hopping gain only for other TRX

Parameter

trxPriorityInTCHAlloc (TRP) 0 = no priority1 = priority for BCCH TRX2 = priority for other TRX3 = priority for BCCH TRX for non-AMR users, priority for other TRX for AMR users

Prioritized TCH Allocation (TRP)Whole band , 50 channels 1 ch=200kHz

BCCH, 30 channels TCH, 20 channels

All 50 channels for BCCH and TCH

Case1

Case2


Enables to differentiate Rx level requirement for:• MS camping to the network /RxLev Access Min• MS accessing to TCH /RX level based TCH access

RX level based TCH allocation method• RX Level measured by the MS is used to determine whether the BTS is

acceptable for TCH allocation• TCH allocation for emergency calls is not restricted due to low RX level

Provides better drop call meters and better performance of MSs• MSs having too low Rx levels are not allowed to camp the networkBy separating camping and TCH access thresholds the operator will be able to provide the maximum camping footprint

RX level based TCH Allocation (RXP)

Note! RG20 feature – Energy optimized TCH allocation


Allows to define minimum C/N ratios separately for each call type (AMR FR, AMR HR, EFR/FR, HR and 14.4 data)Parameter values ‘RX level based TCH access’:

0: RX level based TCH access is not used (C/N definitions not in use)1: RX level based TCH access is used in call setup2: RX level based TCH access is used in call setup and in handovers

Downlink RX Level

-> TCH Access

Soft blocking C/N FR: 0…63dB/ def: 12dB

Soft Blocking C/N HR: 0…63dB/ def: 14dB

Soft blocking C/N AMR FR: 0…63dB/ def: 7dB

Soft blocking C/N AMR HR: 0…63dB/ def: 12dB

Soft blocking C/N 14.4 : 0…63dB/ def: 14dB

RX level based TCH Allocation (RXTA)


Priorities

No TCH available for call set up / handover -> request put into queueDifferent kinds of requests can have different priorities

queuePriorityUsed (QPU) Y/N enables use of priorities

queueingPriorityCall (QPC) 1..14 priority for call set up requestqueuePriorityNonUrgentHo (QPN) 1..14 priority for non urgent handover (power budget,

umbrella, slow moving MS, traffic reason)request

queueingPriorityHandover (QPH) 1..14 priority for urgent handover (all other) request

Queue length and time

maxQueueLength (MQL) 0..100% percentage of number of TCHs handled by BTS timeLimitCall (TLC) 0..15 s time a call set up request is kept in the queue

0 = queuing is disabledtimeLimitHandover (TLH) 0..10 s time a handover request is kept in the queue

0 = queuing is disabled

Queuing (Parameters)


Conditions

Timers set to values > 0User of priorities enabledQueue not full with requests of equal or higher priority than the current one

Queuing of call set up requests

Reservation of SDCCH resources-> SDCCH easily overbooked-> blocking of services like SMS or location update

Queuing (Entering the Queue)


Handover request queued by target BTS

Handover timers hoPeriodPBGT and hoPeriodUmbrella stopped Measurement processing and averaging continues as usual

Intra BSC handover Inter BSC handover

Queuing possibility checked for all possible target cells Order according conventional ranking

Target BTS given by MSC by handover request message

Queuing (Handover)


With TCH allocation

Release of busy TCH Check of queue from top to bottom for best matching request If TCH allocation possible, request removed from queue

Without TCH allocation

Queuing timer expiresRequest of higher priority enters full queue

Queuing (Leaving the Queue)


Directed Retry Timer maxTimeLimitDirectedRetry expires

call cleared, even if still in queue

Queuing timer expires

target cell evaluation continues, if directed retry timer is still running

Queuing (Together with Directed Retry)


BTS does not receive measurement report on SACCH for running call for the first time

Counter initialised with value of radioLinkTimeout (4,8,..64 SACCH periods)

SACCH not received again

Counter decremented by 1

SACCH received again

Counter incremented by 2 (but not beyond initial value)

Counter has value 0

Call release due to radio link time out

Example: short tunnel

Dropped Call ControlRadio Link Timeout


• RLT is based on SACCH deletion but SACCH is though not using a dynamic codec like voice in AMR, which means:

• Using the EFR RLT value an AMR customer can have the call dropped because RLT = 0 when still the FER is good

• RLT is not anymore reliable with the same value in AMR than in EFR• Due to the fact that the FER performance is different when comparing AMR

calls to EFR calls, the Radio Link Timeout need to be defined separately for AMR

• The Radio Link Timeout parameters for AMR are ARLT and AHRLT. The principle of these is the same than in the RLT but it is used only for the AMR capable mobile stations. ARLT & AHRLT are not supported in Talk Family base stations.

Dropped Call ControlRadio Link Timeout


Radio link timeout occurs callReestablishmentAllowed (RE) set to Y

Receive level of BCCH measured for serving and adjacent cell Averaged over 5 s

Strongest cell considered

BCCH decoded C1 cell selection criterion fulfilled Cell not barred

Cell belongs to selected PLMN

Attempt to re-establish call

Successful within 20s *

call re-established

Not successful within 20s * call released

Example: long tunnel

Dropped Call ControlCall Reestablishment

* MAX WAIT TIME OF RE-ESTAB REQ is a modifiable timer in MSC


NPT parameter related (Idle Parameter)


Measurement Processing


MeasurementReport

Standard

• Rx level• Rx quality• Level & BSIC of up to 6 neighbours• 3G cells

Enhanced

Standard + following:• DL frame erasure rate• DTX bit error probability• Real time difference serving – adjacent cell• 3G cells• Control over reporting priority

Measurements

Idle mode

• MS listens to BCCH

Dedicated mode

• MS sends DL measurement report on SACCH• BTS performs UL measurements

Introduction


P (dBm) P (dBm) LEVNo offset 10 dB offset

-110 -100 0-109 -99 1-108 -98 2 . . . . . . . . .-49 -39 61-48 -38 62-47 -37 63

Activation of offset to code high levelsscaleOrd (SCO)(SEG)(0,1,2)(0)

0 = no offset used1 = offset used in general 2 = MS decides automatically about offset

Coding of Rx Level


BER (%) BER (%) QUAL

RANGE MEAN< 0.2 0.14 00.2-0.4 0.28 10.4-0.8 0.57 20.8-1.6 1.13 31.6-3.2 2.26 43.2-6.4 4.53 56.4-12.8 9.05 6> 12.8 18.1 7

Coding of Rx Quality

Average window = 4Quality samples 0,0,7,0WRONG!!: (0+0+7+0)/4 = 1.75 (wrong!!)RIGHT: (0.14+0.14.+18.1+0.14)/4 = 4.63 (right!!) => corresponds to Qual5


BEP BER (%) QUAL

VALUE RANGE22..31 < 0.2 019..21 0.2-0.4 116..18 0.4-0.8 213..15 0.8-1.6 310..12 1.6-3.2 4 7..9 3.2-6.3 5 4..6 6.3-12.6 6 0..3 > 12.6 7

Mapping of BEP to RX Quality


X axis: frame erasure rate (< 1%, 1-5 %, 5-10 %, 10-15 %, > 15 %)Y axis: RX quality (0..7)Z axis: Percentage of measurements for each FER category

Frame Erasure Rate for Handover / Power Control DecisionfepInPcHoUse (FPHO)(BSC)(Y,N)(N)

Mapping of FER to RX Quality


• Decoding of BCCH

• for serving (camped) cell every 30 s• for adjacent cells every 5 min

• Pre-synchronization and decoding of BSIC

• for adjacent cells every 30 s• Adjacent cell list

• Updating every 60 s• BCCH decoding of new cell in 30 s

MS Measurement ExecutionIdle Mode


• Measures RX level and quality for serving cell

• Detects whether DTX is used

26 FRAME MULTIFRAME = 120 ms

TDMA FRAMES

TCH SACCH IDLE

• Measures frequencies of adjacent cells

• BSIC decoding for at least one adjacent cell

• Pre-synchronization on SCH

TDMA FRAMES 4.615 ms

SACCH PERIOD = 480 ms

RX TX RX TX RX TXMEAS MEASMEAS

MS Measurement ExecutionDedicated Mode I


Power Control


• Longer service time of battery• Realization of power class• Supported by default on UL

Reduced interference on DL/UL

Activation of DL power control

powerCtrlEnabled (PENA) Y,N

Power control independent

• for DL and UL• for each call

Power Control Motivation


30 dB Range

Power classdependentrange

Attenuations

Power Values

Maximum MS output power

msTxPwrMaxGSM (PMAX1) 5..39 dBm GSM 900 TCHmsTxPwrMaxGSM1x00 0..36/32,33 dBm GSM 1800/1900 TCH (PMAX2)msTxPwrMaxCCH (TXP1) 5..39 dBm GSM 900 CCHmsTxPwrMaxCCH1x00 0..30 dBm GSM 1800 CCH(TXP2) 0..32 dBm GSM 1900 CCH

Minimum MS output power

minMSTxPower (PMIN) 5..39 dBm GSM 9000..36 dBm GSM 18000..32 dBm GSM 1900

Maximum BTS output power (by minimum attenuation)

bsTxPwrMax (PMAX1) 0..30 dB GSM 900bsTxPwrMax1x00 (PMAX2) 0..30 dB GSM 1800/1900

Minimum MS output power (by maximum attenuation)

bsTxPowerMin 0..30 dB

Power Control ParameterOutput Power Limits


Fixed increment step size

• pcIncrStepSize (INC) 2,4,6 dB

Fixed decrement step size

• pcRedStepSize (RED) 2,4,6 dB

Desired power level can be achieved in 1 or 2 commands

Yes

Fixed step size

No

Variable step size

Power Control ParametersPower Change Step Sizes


UL Level

UL Quality <Av_RXQUAL_UL>

<Av_RXLEV_UL>

DL Level

DL Quality <Av_RXQUAL_DL>

<Av_RXLEV_DL>

POWER CONTROLUPLINK

THRESHOLD COMPARISON

POWER CONTROLDOWNLINK

Power control interval

powerCtrlInterval (INT) 0..31 s

Power Control StrategyMeasurement Averaging


threshold

Actual average samples

Nx samplesLess than Px samples exceed thresholdNo power change triggered

Nx samplesPx samples are equal to or exceed thresholdPower change triggeredSignal level thresholds

pcUpperThresholdLevelDL/UL (UDR/UUR) -110..-47 dBmpcLowerThresholdLevelDL/UL (LDR/LUR) -110..-47 dBm

Signal quality thresholds

pcUpperThresholdQualDL/UL (UDR/UUR) 0..7pcLowerThresholdQualDL/UL (LDR/LUR) 0..7

Number of average samples (for each threshold)

Nx 1..32Px 1..32

Power change step size estimation

Power Control StrategyTriggering


Exceeded threshold Action Reason

pcUpperThresholdLevelDL BTS power decrease Signal levelpcLowerThresholdLevelDL BTS power increase Signal levelpcUpperThresholdLevelUL MS power decrease Signal levelpcLowerThresholdLevelUL MS power increase Signal level

pcUpperThresholdQualDL BTS power decrease Signal qualitypcLowerThresholdQualDL BTS power increase Signal qualitypcUpperThresholdQualUL MS power decrease Signal qualitypcLowerThresholdQualUL MS power increase Signal quality

Power Control StrategyScenarios


AMR Power Control

Exceeded threshold Action ReasonAMR Power Control FR PC Lower Threshold DL Rx Qual

BTS power increase Poor DL signal quality

AMR Power Control FR PC Lower Threshold UL Rx Qual

MS power increase Poor UL signal quality

AMR Power Control FR PC Upper Threshold DL Rx Qual

BTS power decrease Good DL signal quality

AMR Power Control FR PC Upper Threshold UL Rx Qual

MS power decrease Good UL signal quality

AMR Power Control HR PC Lower Threshold DL Rx Qual

BTS power increase Poor DL signal quality

AMR Power Control HR PC Lower Threshold UL Rx Qual

MS power increase Poor UL signal quality

AMR Power Control HR PC Upper Threshold DL Rx Qual

BTS power decrease Good DL signal quality

AMR Power Control HR PC Upper Threshold UL Rx Qual

MS power decrease Good UL signal quality

AMR FR

AMR HR

Details in chapter on AMR


POC

Quality

Signal level

Increasedue to bad Signal level

DecreaseDue to goodSignal level

Increase due to Bad quality

Decrease due to good quality

Qual 0

Qual 7

-110 dB-47 dB

LowerLevel

UpperLevel

UpperQuality

LowerQuality

No action

Ping pong effect


POC

Quality

Signal level

Increasedue to level

DecreaseDue to level

Increase due to quality

Decrease due to quality

Qual 0

Qual 7

-110 dB-47 dB

LowerLevel

UpperLevel

UpperQuality

LowerQuality

6dB

No action


POC and HOC (UL)

Quality

Signal levelQual 0

Qual 7

-110 dB-47 dB

UL Level HOThreshold

No action

UL Quality HOThreshold

When UL quality HO is triggered• Should MS be sent full power?•What about UL level


Power Control Summary

Lower Level Upper Level

Upper Quality

Lower Quality

No actionPower decreasedue to level

Power increasedue to quality

Power increasedue to levelor quality

Power increasedue to quality

Power decreasedue to levelor quality

Power increasedue to level

Power decreasedue to quality6 dB

Power increasedue to level

Qual 0

Qual 7

-110 dBm -47 dBm


pcLowerThresholdsLevelDL/UL

Power control triggeredUL: Power increase of MSDL: Power increase of BTS

RXLEV_DL/UL > pcLowerThresholdLevelDL/UL - 2 powerIncrStepSize

Yes

Fixed step size

PWR_INCR_STEP = powerIncrStepSize

No

Variable step size

PWR_INCR_STEP = pcLowerThresholdLevelDL/UL – RXLEV_UL/DL

Actual receive level RXLEV_DL/UL

Power Increase Due to Signal LevelFor MS & BTS


pcUpperThresholdsLevelDL

Power control triggeredPower decrease

Yes

Fixed step size

PWR_DECR_STEP = powerDecrStepSize

No

Variable step size

PWR_DECR_STEP = Min (RXLEV_DL – pcUpperThresholdLevelDL, 10)

Actual received level RXLEV_DL

RXLEV_DL < pcUpperThresholdLevelDL + 2 powerDecrStepSize OR

variableDLStepUse (VDLS) = No

Power Decrease Due to Signal LevelFor BTS


pcUpperThresholdsLevelUL

Power control triggeredPower decrease

Yes

Fixed step size

PWR_DECR_STEP = powerDecrStepSize

No

Variable step size

PWR_DECR_STEP = RXLEV_UL – pcUpperThresholdLevelUL

Actual received level RXLEV_UL

RXLEV_UL < pcUpperThresholdLevelUL + 2 powerDecrStepSize

Power Decrease Due to Signal LevelFor MS


pcLowerThresholdsQualDL/UL

Power control triggeredUL: Power increase of MSDL: Power increase of BTS

Actual receive quality RXQUAL_DL/UL

Variable step size based on actual quality

PWR_INCR_STEP = (1 + Max (0,QUAL)) * powerIncrStepSize

QUAL = RXQUAL_DL/UL – pcLowerThresholdQualDL/UL

Step size based on actual level

Take algorithm for power increase due to signal level

Take largest step size

Power Increase Due to Signal QualityFor MS & BTS


pcUpperThresholdsQualDL/UL

Power control triggered

Actual received quality RXQUAL_DL/UL

Actual RXLEV_DL/UL – pcLowerThresholdLevelDL/UL < 6 dB

Yes No

No power decrease

Avoid ping pong effect

Power decrease

Take algorithm for power decrease due to signal level(different for MS & BTS power decrease)

Power Decrease Due to Signal QualityFor MS & BTS with No Power Optimization


NPT parameter related (POC Parameter)

Should be greater than HOC


Handover Control


Intra cellOnly other carrier / timeslot

Inter cellIntra BSC

Inter BSCIntra MSC

Inter MSC

Inter PLMNGlobal Cell ID requiredMCC + MNC + LAC + CI

Germany Czech Republic

Intra PLMNSimple Cell ID requiredLAC + CI

Handover Types


Multi Layer Network Types

Coverage Layer: Gives access to the networkCapacity Layer: Provides additional capacity and allows traffic distribution

Macro cells

Micro cells Intelligent Underlay OverlayDifferent frequencies for high / low power TRx

Normalfrequency

Super reusefrequency

GSM 900 cellGSM 1800 cell


threshold

Actual average samples

Nx samplesLess than Px samples >= thresholdNo handover triggered

Nx samplesPx samples are >= thresholdhandover triggered

Signal interference thresholdshoThresholdsInterferenceDL/UL (IDR/IUR) -110..-47 dBm

Signal quality thresholdshoThresholdsQualDL/UL (QDR/QUR) 0..7

Signal level thresholdshoThresholdLevelDL/UL (LDR/LUR) -110..-47 dBmhoThresholdRapidLevelUL (RPD) -110..-47 dBm

MS speed thresholdsupper/lowerSpeedLimit (USL/LSL) 0..255 (unit = 2km/h)

Number of average samplesNx 1..32Px 1..32

Target cell selection

Handover StrategyTriggering

Trigger Point – When the set threshold has been met or exceeded Px times of Nx times


More than one handover criterion fulfilled -> process of higher priority performedHandover and power control criteria fulfilled -> handover performed

1) Interference (uplink or downlink)2) Intra-segment inter-band because of downlink level (from higher to lower frequency band) 3) Uplink quality4) Downlink quality5) AMR unpacking (uplink level and also uplink unpacking quality triggers)6) Uplink level7) AMR unpacking (downlink level and also downlink unpacking quality triggers)8) Downlink level9) Coverage based inter-system handover to WCDMA RAN10) IMSI-based inter-system handover to WCDMA RAN11) IMSI-based handover12) DTM-based handover to WCDMA RAN13) Inter-system handover to WCDMA RAN14) MS-BS distance (maximum or minimum)15) Turn-around-corner MS16) Rapid field drop17) Slow/fast-moving MS18) Umbrella19) Power budget20) DTM-based handover to a GSM DTM cell21) BSC-initiated TRHO22) IUO23) Intra-segment HO based on load24) AMR packing because of good uplink and downlink quality25) AMR unpacking because of bad uplink or downlink quality26) PC because of lower quality thresholds (uplink and downlink)27) PC because of lower level thresholds (uplink and downlink) 28) PC because of upper quality thresholds (uplink and downlink)29) PC because of upper level thresholds (uplink and downlink)

Handover Strategy(Priorities)

Exercise:Whu UL has many times higher priority than DL?


HO due to UL/DL QualityIF

AV_RXQUAL_DL_HO >=HoThresholdsQualDL

THENHandover cause Downlink quality

IFAV_RXQUAL_UL_HO >=

HoThresholdsQualULTHEN

Handover cause Uplink quality

Target cells is listed based on below criteria1. AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0,Pa)

2.AND IFEnableHoMarginLevQual(n)= Yes

THENAV_RXLEV_NCELL(n) > AV_RXLEV_DL_HO + (BsTxPwrMax - BS_TXPWR)

+ HoMarginQual(n)3. ELSE

PBGT(n) > HoMarginPBGT(n) (2)

Order of preference of target cellsPRIORITY(n) = HoPriorityLevel(n) - HoLoadFactor(n)

HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded.

Interval between handovers and handover attempts

Listing set of target cell

Priority of target cell

Timer of source cell


HO due to UL/DL LEVELIF

AV_RXLEV_DL_HO<=HoThresholdsLevDL

THENHandover cause Downlink level

IFAV_RXLEV_UL_HO<=HoThresholdsLevUL

THENHandover cause Uplink level

Target cells is listed based on below criteria1. AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0,Pa)

2.AND IFEnableHoMarginLevQual(n)= Yes

THENAV_RXLEV_NCELL(n) > AV_RXLEV_DL_HO + (BsTxPwrMax - BS_TXPWR)

+ HoMarginLev(n) 3. ELSE

PBGT(n) > HoMarginPBGT(n) (2)


HoLoadFactor value is taken into account when BTSLoadThreshold is exceeded.

GUARD_TIME = 2 * HoPeriodPBGT (Ho Due PBGT)GUARD_TIME = 2 * HoPeriodUmbrella (HO Due to Umbrella)

Listing set of target cell

Priority of target cell

Timer of source cell


HO due to Fast/Slow moving MSMS speed in relation to cell size:

IFMsSpeedDetectionState= 0

AdjCellLayer(n) = LowerFastMovingThreshold(n)> 0

Measured MS speed:IF

AV_MS_SPEED <= LowerSpeedLimitTHEN

MS is slow-movingIF

AV_MS_SPEED >= UpperSpeedLimitTHEN

MS is fast-moving

AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX (0, Pa)

THENRXLEV_CNT(n) = RXLEV_CNT(n) + 2

ELSERXLEV_CNT(n) = RXLEV_CNT(n) - 1

IFRXLEV_CNT(n) >=

FastMovingThreshold(n)THEN

Handover cause Slow-moving MS

Target cell evaluation:AdjCellLayer(n) = Lower/Upper

ANDAV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1')

Handover to low layer cell is not possible if maximum power capability of MS exceeds gsm/dcsMicrocellThreshold

IFMsSpeedDetectionState= 0

THENHandover Cause Fast/Slow-moving MS

ELSEScale averaging parameters


HO due to Fast/Slow moving MS (Count)Target cell evaluation:

AdjCellLayer(n) = Lower/UpperAND

AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1')Handover to low layer cell is not possible if maximum power capability of MS exceeds

gsm/dcsMicrocellThreshold


HoLoadFactor value is taken into account whenBTSLoadThreshold is exceeded



HO due to Umbrella

IFEnableUmbrellaHO= Yes

HoPeriodUmbrella - interval between the umbrellahandover threshold comparisons

Umbrella handover and target cell evaluation:AV_RXLEV_NCELL(n) > HoLevelUmbrella(n) (1')

AND( [(P >= macro_thr) AND (pwr(n) >= macro_thr)]

OR[(P <= micro_thr) AND (pwr(n) <= micro_thr)]

OR[(P < macro_thr) AND (pwr(n) < macro_thr) AND

(P > micro_thr) AND (pwr(n) > micro_thr)] )


Order of preference of target cellsPRIORITY (n) = HoPriorityLevel(n) - HoLoadFactor(n)

HoLoadFactor value is taken into account whenBTSLoadThreshold is exceeded.


Umbrella handover to 1800 cell

A

B

900 ‘Macro’

hoLevelUmbrella = -85 dBmgsmMacrocellThreshold = 33 dBmdcsMacrocellThreshold = 33 dBm

Threshold RX level handover –95 dBm

Threshold umbrella handover –85 dBm

PTCH (msTxPwrMax(n)) = 30 dBm -> micro cellPMAX = 30 dBm -> handover to micro cell onlyhoThresholdLevelDL = -95 dBm

1800 ‘Micro’

RX level handoverback to 900 cell

Umbrella +FMT HandoverExample

After FMT>1 (example)


HO due to PBGT

IFEnablePowerBudgetHO= Yes

HoPeriodPBGT - interval between the power budgetthreshold comparisons

Power budget and target cell evaluation:AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1)

ANDPBGT(n) > HoMarginPBGT(n) (2)

PBGT(n) = (B - AV_RXLEV_DL_HO -(BsTxPwrMax - BS_TXPWR)) - (A - AV_RXLEV_NCELL(n))


Order of preference of target cellsPRIORITY (n) = HoPriorityLevel(n) - HoLoadFactor(n)

HoLoadFactor value is taken into account whenBTSLoadThreshold is exceeded.


Serving cell: AHO candidate target cells: B, C, D

All cells have the following parameter set:rxLevMinCell= -99 dBmmsTxPwrMax= 33 dBmbtsTxPwrMax= 42 dBmhoMarginPBGT= 6 dB

Target cell ‘hoPriorityLevel’:B priority: 4C priority: 3 D priority: 3

Target cell ‘HOLoadFactor’:B load factor: 2C load factor: 1D load factor: 1

Target cell B is considered overloaded

BTS BTS

BTS

BTSBSC

A B

C

D

Which cell (B/C/D) will be chosen as target for the Power Budget HO?

AV_RXLEV_NCELL (B)= -80 dBmAV_RXLEV_NCELL (C)= -83 dBmAV_RXLEV_NCELL (D)= -85 dBm

Serving cell A:AV_RXLEV_DL_HO= -92 dBmBTS_TX_PWR= 42 dBm

Exercise Solution

Power Budget HandoverExercise


enablePowerBudgetHo = Yes & enableUmbrellaHo = YesPower budget handover to cells of the same layerUmbrella and FMT handover to cells of different layer

Combined Umbrella & Power Budget HOOverview

macrocells

microcells

RR

PBGT,RR

PBGT,RRUMBR+FMT

UMBR umbrella HORR radio reason HOPBGT power budget HO


UPPER layer (macro)

SAME layer (serving layer)

LOWER layer (micro)

Predefinition of layer possible by adjCellLayer (ACL)Three layers visible relative to serving cellUsed for target cell evaluation• Combined umbrella and power budget • Handover based on MS speed• Fast moving MS handling in macro cell

N (no predefinition)

Combined Umbrella & Power Budget HOAdjacent Cell Classification


HO due to Directed RetryIF

DirectedRetryUsed = YesHandover from SDCCH of serving cell to TCH of adjacent cell due to congestion

minTimeLimitDR – Target cell evaluation startedMaxTimeLimitDR - Target cell evaluation stopped

Target Cell evaluationIF

DirectedRetryMethod = 1THEN

AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1)AND

AV_RXLEV_NCELL(n) > DRThresholdELSE

AV_RXLEV_NCELL(n) >RxLevMinCell(n) + MAX (0,Pa)



No TCH available during call set up in serving cell -> handover to TCH of other cell

Must be enabled withdrInUse (DR) Y/N

Thresholds to be exceeded by target cell according condition (1a)drMethod (DRM) 0/1 Defined type of thresholdrxLevMinCell -110..-47 dBm Used if drMethod = 0drThreshold (DRT) -110..-47 dBm Used if drMethod = 1 and

drThreshold > rxLevMin CellTimers (to be counted from TCH assignment)minTimeLimitDirectedRetry (MIDR) 0..14 s No target cell evaluation

allowedmaxTimeLimitDirectedRetry (MADR) 1..15 s Target cell evaluation allowed

SDCCHTCH

congested TimeAssignmentRequest

minTimeLimitDR

maxTimeLimitDR

DR not allowed DR allowed

Directed RetryParameters


HO due to Rapid Field Drop

IFHoThresholdsRapidLevUL/Px > 0

IFPx number of RXLEV_UL measurement < HoThresholdsRapidLevUL

THENHandover cause Rapid field drop

Target cell evaluationIF

ChainedAdjacentCell(n) = YesAND

AV_RXLEV_NCELL(n) > RxLevMinCell(n) + MAX(0, Pa) (1)

Order of preference of target cells:The target cells are ranked according to radio link properties

(equation 1).


Chained Cell

1st

2nd

Serving cell

hoThresholdRapidLevUL = -93 dBmhoThresholdRapidLevUlN = 2chainedAdjacentCell = Y

Threshold rapid field drophandover –93 dBm

Handover triggered

Serving Cell

Rapid Field Drop HandoverExample


NPT parameter related (HOC Parameter)

Should be lower than POC


NPT parameter related (ADCE Parameter)


KPI case


Optimization Principle

service quality

cell coverage cell capacity

Optimizationand Tailoring

Optimization process is a way to do changes in a network so that those network have

maximum on Capacity, Coverage and Quality

Excessive value RxLevAmi will improve KPI but coverage

and quality will reduce

Site with height >40m with total tilt =2 will have wide coverage but KPI will bad

Site with FRL/FRU = 100% will have max capacity but have

lower Quality


KPI- Rules, SDCCH BlockingSDCCH Blocking

>X%

Is dynamic sddch active

Is dynamic sdcch reaching max values

in some moment

Is combined sdcch used

yes

yes

Check unavailability in the cells,

averarage available sdcch

Availability OK

Check sdcch blocking. Can sdcch capacity be added

without tch blocking

SDCCH blocking is high

yes

No

Yes, remove combined sdcch

No, check parameterValues and make

corrections

No, activateDynamic sdcch

Yes, make corrections

Case closedNo

Yes, add sdcch capacity

Add TRX and add Sdcch capacity

sdcch Blocking is still high

No

Yes

Is high sdcch traffic due to Location updates. If yes, can LU area be optimized? Check also PRAU parameter, can the value

be increased?

noYes, Optimize LU

area border

no

ND_211ND_130Cngt_2Blck_5

Blck_5b

ND_139,ND_131ND_130, uav_22

csf_1a,csf_11Ava_45a

ND_211c1154

ND_211c2032

NetAct PlannerP_nbcs_cc_pm

ND_211

If SDCCH block high please check:1.TCH/SDCCH availability2.LOC design (SDCCH traffic profile)3.Parameter (CRO, CRH, RxLevAmi)


KPI- Rules, SDCCH Drop

SD DCR > 2% andSD DCRnum > 10

Drops due to RF Reasons

Drops due to Abis ReasonsNo

Drops due to A-interface Reasons

No Drops due to other ReasonsNo

Case ClosedNo

RF Abis A Other

Yes Yes Yes Yes

Yes

No

ND_166

If SDCCH drop high please check:1.DL/UL Quality2.CRO/CRH, TRP setting3.TA profile – overshooting possibility4.SDCCH TS location


KPI- Rules, SDCCH Drop due to RF/Abis


KPI- Rules, SDCCH Drop due to Aif


KPI- Rules, SDCCH Drop (A)

A>X%

A interface problems. Alarms are checked and A interface trace is

done

Investigate alarms.If problems

are not solved, activate A trace

Any improvements

Any problems found. Trace

was long enough

Make corrections

Check ET lines in the BSC and

transcoders /TCSM. Any problems

Repair ET lines

Still A drops or problems

No

Activate

No

No

Yes

Yes

Alarms Are

Solved

Yes

Trace was not long

enough

Case Closed

Yes

No

Trace was Long enough. Not

An problem was found

Investigate log files. Check DX

causes, see document Call

related DX causes in BSC

No

alarms


KPI- Rules, SDCCH Drop (other)

Other

Lapd fails BTS fails Netw ActFails

User Act, bcsu, resets

Still lots of other drops

Check all the alarms

signalling fails or PCM fails.

Check transmissio / parameters

Yes

No

TRX or BTS fails. Check

that BTS/ TRX are working

properly

Yes

No

Configuration problems,

check configurations

Yes

No

Resets or act fail channel

failures

Yes

No

Case Closed No

Yes


KPI- Rules, TCH Block


TCH SEIZURES FOR NEW CALLtch_norm_seiz /c1009+tch_seiz_due_sdcch_con /c1099 (S5)+msc_i_sdcch_tch /c4044 +bsc_i_sdcch_tch /c4057+cell_sdcch_tch /c4074-tch_succ_seiz_for_dir_acc /c1165 (S7)

-tch_re_est_assign /c57032 (S7)

TCH DROPS AFTER SEIZURETCH_RADIO_FAIL /c1013+TCH_RF_OLD_HO /c1014+TCH_ABIS_FAIL_CALL /c1084+TCH_ABIS_FAIL_OLD /c1085+TCH_A_IF_FAIL_CALL /c1087+TCH_A_IF_FAIL_OLD /c1088+TCH_TR_FAIL /c1029+TCH_TR_FAIL_OLD /c1030+TCH_LAPD_FAIL /c1046+TCH_BTS_FAIL /c1047+TCH_USER_ACT /c1048+TCH_BCSU_RESET /c1049+TCH_NETW_ACT /c1050+TCH_ACT_FAIL_CALL /c1081

-tch_re_est_assign /c57032 (S7)

DROPS

CALLS

100 * %

STARTED CONVERSATIONSconver_started /c57015- msc_i_tch_tch /c4043

CONVERSATION DROPSdropped_calls /c57007

TCH DROPS AFTER ASSIGNMENTtch_new_call_assign /c57033+tch_ho_assign /c57034

-tch_norm_release /c57035-tch_ho_release /c57036

-tch_re_est_assign /c57032

TCH ASSIGNMENTS FOR NEW CALLtch_new_call_assign /c57033

-tch_re_est_assign /c57032

TCH RELEASEDisconnect from MS

RF CHN RELEASERf_channel_release_ack from BTS

CONVERSATION STARTED conn_ack to BTS

TCH ASSIGNED Assignment_complete from BTS

TCH SEIZED BSC allocates a TCH as a response toTCH request (Channel Activation)

Dcr_8hDcr_5a

Dcr_3j

KPI- Rules, TCH Drop Call Ratios

http://nea.ntc.nokia.com/cgi-bin/cgiwrap/neva/counters?001009






KPI- Rules, TCH Drop due to RF/Abis


KPI- Rules, TCH Drop due to RF Old


How unnecessary HO happened??

GSM

DCS

RxLev = -80dBmCRO=0

RxLev = -95dBmCRO=23HO threshold = 20

On idle mode received level for GSM is -80 dBm while DCS can be (-95 dBm + (2 x 23) -49dBm

On dedicated mode user will move from DCS to GSM due to DCS level already too low

Unecessary HO can lead to DCR due to RF Old and HO fail (ex. Due to GSM blocking)


How unnecessary HO happened??

GSM/DCS A GSM/DCS B

Call establish on cell A, then received level drop below HO threshold. User will move from cell A to cell B

After user serve by cell B, cell B will ask user to do handover as received level on cell B already below HO threshold.

RxLev = -95dBmHO threshold = 20RxLevmin from A to B = 12

RxLev = -92dBmHO threshold = 20RxLevmin from A to B = 12


KPI- Rules, TCH Drop due to Aif


KPI- Rules, TCH Drop due to Transcoder


KPI- Rules, TCH Drop

DCR > X% andDCRnum > XX

Drops due to RF Reasons

Drops due to Abis ReasonsNo

Drops due to A-interface Reasons

NoDrops due to Transcoder Reasons

No Drops due to other ReasonsNo

Case Closed No

RF Abis A TR Other

Yes Yes Yes Yes Yes

Yes

No

ND_163


KPI- Rules, TCH Drop (Other)

Other

Lapd fails BTS fails Netw ActFails

User Act, bcsu, act fails

Still lots of other drops

Check all the alarms

signalling fails or PCM fails.

Check transmissio / parameters

Yes

No

TRX or BTS fails. Check

that BTS/ TRX are working

properly

Yes

No

Configuration problems,

check configurations

Yes

No

Resets or act fail channel

failures

Yes

No

Case Closed No

Yes


KPI- Rules, coverage problems (dlq_2a and ulq_2a)

Here are some examples how different kind of problems can be found

Like Normal distribution HW Problem, TRX/combiner etc is brokenQ0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7

CL10 10645 8516 6813 5450 4360 3488 2791 2232 CL10 5323 4258 3406 2725 2180 1744 4563 9765CL15 47043 37634 30108 24086 9865 7543 5643 2345 CL15 11761 9409 7527 6022 9383 1886 65432 7675CL20 56204 44963 35971 28776 6574 10324 345 65 CL20 14051 11241 8993 7194 18271 2581 65438 63562CL30 200863 160690 128552 102842 17654 9876 145 28 CL30 33772 27017 21614 17291 75037 2469 18765 14523CL40 12785 10228 8182 6546 456 112 24 23 CL40 3196 2557 2046 1636 4938 28 3659 2648CL63 4583 1123 583 452 261 76 26 2 CL63 1146 281 146 113 3378 19 100 174

HW problem, Q4 amount of samples is strange Interference problemQ0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7

CL10 5323 4258 3406 2725 2180 1744 1395 1116 CL10 5323 4258 3406 2725 2180 1744 1395 1116CL15 23522 18817 15054 12043 18765 3772 2822 1173 CL15 23522 13234 10588 8470 13234 10588 8470 6776CL20 28102 22482 17985 14388 36542 5162 173 33 CL20 28102 2123 1699 1359 2123 1699 1359 1087CL30 67544 54035 43228 34582 150073 4938 73 14 CL30 67544 3634 2908 2326 3634 2908 2326 1861CL40 6393 5114 4091 3273 9876 56 12 12 CL40 6393 4091 3273 2618 4091 3273 2618 4532CL63 2292 562 292 226 6756 38 13 1 CL63 9987 7543 4323 3454 2275 1187 876 654

HW Problem, TRX/combiner etc is brokenQ0 Q1 Q2 Q3 Q4 Q5 Q6 Q7

CL10 200863 160690 128552 102842 17654 9876 7865 6543CL15 16543 13234 10588 8470 6776 2822 1173 234CL20 2654 2123 1699 1359 1087 173 33 65CL30 4543 3634 2908 2326 1861 73 14 28CL40 5114 4091 3273 2618 2095 12 12 23CL63 24 54 8 87 7 0 0 0

1

2

3

1. Lots of Q4 samples. Distribution is not OK HW problem. Site reset will help2. Lots of bad signal level samples. TRX/Combiner is broken. If no HW problem

Site is totally in wrong place, site is like transferring traffic to another cell ( cause level HO). Typically a HW problem

3. Lots of Q6 and Q7 samples. Distribution is not OK, no Q5 samples HW problems. Site reset or broken TRX

4. Typical normal interference problem.

Here are some examples how different kind of HW problems can be found

4


KPI- Rules, Interference analysis DL /UL

Rx Quality x Rx Level

Coverage Problem:Bad quality and Low Rx Level

Interference Problem:Bad quality and High Rx Level

Good Quality

High Rv Level

HW Problem:Bad Quality for all Rx Levels

NWD report 204 model

HW ProblemAll samples below -100dBmCL10 <-100dBm

Same level – quality distribution for both UL and DL


KPI- Rules, Interference, UL

q0 q1 q2 q3 q4 q5 q6 q7-100dBm 10645 8516 6813 5450 4360 3488 2791 2232-95dBm 47043 37634 30108 24086 9865 7543 5643 2345-90dBm 56204 44963 35971 28776 16574 5676 845 65-80dBm 200863 160690 128552 102842 17654 3653 145 28-70dBm 1234 987 790 632 505 404 323 259-47dBm 24 19 15 12 10 8 6 5

MS power control can be seen here. If Power is reduced → no bad UL problems. BSC border is increasing good level samples


Bad interference problems. By POC parameter interference can be decreased, how power is adjusted etc. Also optimum MS power feature improves UL interference, no full power is sent after HO.


Bad quality sample due to signal level problems. Diversity should be checked, also possibilities to use LNA to improve UL signal level. Antenna place should be also checked if there are some obstacles near the antenna.


KPI- Rules, Interference, UL, examples

UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7 DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7-100dBm 251992 30668 20552 18417 18156 18286 16983 12478 27862 5537 5529 6069 6109 6107 5389 4119-95dBm 123653 1151 403 692 519 351 221 72 89094 4236 3853 3576 2893 2264 1372 584-90dBm 62938 247 144 288 353 129 62 29 142228 2732 2550 2356 1510 1114 774 404-80dBm 27005 51 65 149 177 82 40 16 222462 1523 1355 1552 716 812 1081 343-70dBm 2831 3 9 28 87 10 6 0 44504 91 123 151 81 101 191 88-47dBm 751 0 4 10 25 1 0 0 5994 49 17 17 12 29 65 10

Huge amount of UL bad samples. Cells is not working properly, it is like transferring traffic, UL quality/ UL level HO’s are triggering immediately. These kind of cells must be investigated.

UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7-100dBm 490 137 368 605 1014 1378 1830 2586-95dBm 8410 3768 3225 3023 2767 2304 1561 1859-90dBm 38512 5249 3066 2323 1692 1570 1191 1268-80dBm 219137 4600 2453 2311 1470 1724 1864 1221-70dBm 509591 2504 1812 3050 1271 1465 1649 337-47dBm 244302 582 711 1363 1713 873 671 87

UL_q0 UL_q1 UL_q2 UL_q3 UL_q4 UL_q5 UL_q6 UL_q7-100dBm 70004 5020 3500 2564 2232 1946 2190 2579-95dBm 80339 392 286 461 328 250 275 92-90dBm 106883 233 318 602 199 146 234 64-80dBm 246892 227 314 860 298 338 395 60-70dBm 254875 155 298 935 203 135 166 15-47dBm 23288 21 27 103 109 11 41 0

Some UL interference in good signal level. UL power control is not working properly. Ul power control is good indicator, if power is adjusted, there are no big problems in UL direction

There is no UL interference, or just a little. MS is adjusting power properly, there are only little samples in good UL signal level.



KPI- Rules, Interference, DL

Bad interference problem → signal level good (<-80dBm) and sometimes no better cell available. If better cell available and quality samples are 4 or worse → HO (reason quality or interference, depends on the parameter) Interference is causing drops.

Really bad interference problem → signal level is really good (<-70dBm) and usually no better cell available → no HO → samples can be seen in the table. Interference is causing drops.

Situation is “network is working properly” If there are quality 4 or worse samples → quality HO. Most of the samples are q4 samples. If lots of q5..q7 samples → interference problem and interference must be analyzed / removed. If quality HOs but no q5..q7 samples → better cell is available → no interference problems. In these signal levels overlapping exists and if handover reason is no PBGT, it will be quality HO. By parameter amount of quality HOs can be adjusted




Bad quality samples due to signal level problems. If PBGT overlapping is not existing → lots of quality HOs + level HOs (margin are lower than in PBGT). Not interference problem, more signal level problem.

Check how much samples vs. HOs → are better cells available or not.


KPI- Rules, Interference, DL, examples

DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7-100dBm 12057 2827 3108 3952 4783 6200 7013 8156-95dBm 44818 4811 5041 5866 6587 7223 7259 6781-90dBm 98587 7107 7400 8334 8470 8781 7825 6162-80dBm 225919 7450 7731 8445 7726 7441 5695 3369-70dBm 88708 1014 971 998 751 688 689 367-47dBm 15881 84 109 122 104 167 199 184


There are almost as much samples Q5 and Q7 samples as Q 4 samples → even interference is really bad or there is no better cell available ( no ho’s after bad quality samples). These kind of interference cells should be optimized, otherwise there are lots of drops etc

There are no as much Q5…Q7 samples as Q4 samples → after interference samples Quality HO is done or the interference situation is not so bad, for example sampling is Q0,Q2,Q4,Q2,Q5,Q0,Q2,Q3,Q4,Q2 → quality HO is not triggering


There are bad quality samples only due to signal level problems.


KPI- Rules, Interference (internal / external)

•Internal Interference– Interference can be seen from stats or can be measured by scanner.– Neighbor cells (DL) or mobiles (UL) are causing interference.– By frequency / network planning interference can be decreased.

•External Interference– Interference can be seen from stats or can be measured by scanner.– External radio frequencies are causing interference

Military use In the border area, interference is coming from other country. Some external wireless system (for example some wireless industry system)

is causing interference Increased I level can be also due to external interference


KPI- Rules, HOSR


KPI- Rules, HO fail

sum(msc_o_succ_ho + bsc_o_succ_ho + cell_succ_ho) Total HO success ratio = 100 * (-------------------------------------------------------------------------------- ) (ho_65)

sum(msc_o_ho_cmd + bsc_o_ho_cmd_assgn + bts_ho_assgn)

sum(a.msc_o_succ_ho + a.bsc_o_succ_ho + a.cell_succ_ho + a.msc_to_wcdma_ran_succ_tch_ho)

Total HO failure ratio = 100 * (1- -------------------------------------------------------------------------------------) (hfr_2b) sum(b.msc_o_ho_cmd + b.bsc_o_ho_cmd_assgn +

b.bts_ho_assgn+a.msc_gen_sys_wcdma_ran_ho_com)

/* handovers failing due to blocking */ sum(a.msc_o_fail_lack + a.bsc_o_fail_lack + a.cell_fail_lack

+ a.msc_to_wcdma_ran_fail_lack) HO failure ratio due to RF blocking = 100 * --------------------------------------------------------------------------------------- /* all HO attempts */ sum(b.msc_o_ho_cmd + b.bsc_o_ho_cmd_assgn +

b.bts_ho_assgn + a.msc_gen_sys_wcdma_ran_ho_com)

(hfr_55a)

2g training optimization

Documents