2- omo133000 bsc6900 gsm v9r13 ms behaviors in idle mode issue 1.00

www.huawei.com

Copyright © 2011 Huawei Technologies Co., Ltd. All rights reserved.

英文标题 :40-47pt

副标题 :26-30pt

字体颜色 : 反白内部使用字体 :

FrutigerNext LT Medium

外部使用字体 : Arial

中文标题 :35-47pt

字体 : 黑体副标题 :24-28pt

字体颜色 : 反白字体 : 细黑体

GSM MS Behaviors in Idle Mode


Foreword Once the MS is power on and there is a live network exist, the MS

will be in either idle mode or dedicated mode.

In idle mode, the MS has no dedicated connection with network, but it is still controlled by the many parameters and functions in the system.

The MS behaviors in idle mode include: System information reception

Cell selection and reselection

Location update

Paging processing

Access processing.

There are also some other parameters to be introduced which is related with the future processing of network access.

Page2


Objectives

Upon completion of this course, you will be able to:

Describe the working principles of the MS Behaviors in

Idle Mode feature

Perform parameters modification of the MS Behaviors

in Idle Mode feature

Get to know other parameters which related with the

future processing after network access.

Page3


Contents

1. System Information Reception

2. Cell Selection

3. Cell Reselection

4. Location Update

5. Paging Processing

6. Access Processing

7. Other parameters

Page4


System Information Reception

By reading system information, MS can access the network, perform cell selection and reselection, fully utilize various services provided by the network, and achieve favorable cooperation with the network.

System information (SYS INFO) contains network parameters sent to MS through Um interface

network identity parameters

cell selection parameters

system control parameters

network function parameters

System information can be sent through two kinds of logical channels

System information on BCCH

System information on SACCH

Page5


SYS INFO 1

SYS INFO 1

It contains random access control information (RACH)

and cell frequency allocation table (i.e. CA table). It is

transmitted on BCCH.

Content

SYS INFO 1

Cell Channel Description

(cell channel description format)

RACH Control Parameter

(random access channel control parameter)

Page6


SYS INFO 2

SYS INFO 2

It contains access control information (RACH), network color code

permitted (NCC Permitted), and neighbor cell frequency allocation list

(BA1 list). It is transmitted on BCCH. Generally speaking, SYS INFO 2,

2BIS, 2TER contains different parts of the neighbor cell’s BCCH

frequencies. Via reading and decoding BA1 list, MS can perform cell

reselection in idle mode. For a MS of GSM900 PHASE I, it only reads

the neighbor cell BCCH frequencies defined in SYS INFO 2, and

ignores those carried by 2BIS and 2TER.

Content

SYS INFO 2

Neighbor Cell BCCH Frequency Description

NCC Permitted


Page7


SYS INFO 2BIS

SYS INFO 2BIS

2BIS contains RACH control data and neighbor cell’s BCCH

frequencies (part of BA1 list). It is optional and transmitted on

BCCH. As the number of frequencies in BA1 list carried by SYS

INFO 2 is limited, SYS INFO 2BIS carries the rest of the BCCH

frequencies in the BA1 list that are from the same band as in

SYS INFO 2.

Content

SYS INFO 2BIS

Neighbor Cell Description.

RACH Control Parameter (Same as those in SYS INFO 1)

Page8


SYS INFO 2TER

SYS INFO 2TER

2TER contains neighbor BCCH frequencies (part of BA1 list). It

is transmitted on BCCH. Only dual band MS can read this

information, and single band 900 or 1800 MS will ignore it.

Since this information carries BCCH frequencies that belong

to different band other than those in SYS INFO 2, it is

unnecessary for single band MS to read.

Content

SYS INFO 2TER

Neighbor Cell Description (extended)

Page9


SYS INFO 3

SYS INFO 3 It contains LAI, cell identity, RACH control parameters and

cell selection related parameters. It is transmitted on BCCH. It is one of the most important information.

Content SYS INFO 3

Cell Identity

LAI (location area identity)

Control Channel Description

Cell Option

Cell Selection Parameter


Page10


SYS INFO 4 SYS INFO 4

It consists LAI, RACH control parameters, cell selection parameters and

optional CBCH channel information. It is transmitted on BCCH. When

the cell supports cell broadcast function, CBCH together with CBCH MA

describe the configuration of CBCH the relevant frequency information.

Content

SYS INFO 4

LAI

Cell Selection Parameter


CBCH Channel Description (optional)

CBCH Mobile Allocation (optional)

SI4 Rest Octets (parameters related to cell reselection)

Page11


SYS INFO 5

SYS INFO 5 It describes the neighbor cell BCCH frequencies(BA2 list). It is

mandatory and is transmitted on SACCH. Different from SYS INFO 2, MS can read the frequency described in SYS INFO 5 in dedicated mode, report the relevant information of neighbor cells in measurement reports, and use it as the basis for handover. Similarly, for 900 MS of PHASE 1, it only recognizes the neighbor cell frequencies described by SYS INFO 5, and ignores those carried by SYS INFO 5BIS and 5TER.

Content SYS INFO 5

Neighbor Cell Description

Page12


SYS INFO 5BIS

SYS INFO 5BIS

5BIS describes neighbor cells’ BCCH frequencies.These

frequencies are part of BA2 list. It is optional and is

transmitted on SACCH. Generally, as the number of

frequencies which can be described by SYS INFO 5 is limited,

SYS INFO 5BIS carries the rest BCCH frequencies in the BA2

which belong to the same band as SYS INFO 5.

Content

SYS INFO 5BIS

Neighbor Cell Description

Page13


SYS INFO 5TER

SYS INFO 5TER

5TER describes neighbor cells’ BCCH frequencies, these

frequencies are also a part of the BA2 list. It is transmitted on

SACCH. Similarly, only dual band MS can read this

information, and single band GSM900 or GSM1800 MS will

ignore it. It carries the BCCH frequencies of neighbor cells

whose band are different from the serving cell’s.

Content

SYS INFO 5TER

Neighbor Cell Description (Extended)

Page14


SYS INFO 6

SYS INFO 6

It describes LAI, cell identity, and some parameters

describing the cell’s functions. It is transmitted on SACCH. It

is also one of the most important system information.

Content

SYS INFO 6

Cell Identity

LAI

Cell Option

NCC Permitted

Page15


Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page16


Cell Selection/Reselection Parameters RXLEV-ACCESS-MIN

MS_TXPWR_MAX_CCH

CBQ (Cell_Bar_Qualify)

CBA (Cell_Bar_Access)

CRO (Cell Reselection Offset)

TO (Temporary Offset)

PT (Penalty Time)

PI (Cell Reselect Parameters Indication)

CRH ( Cell Reselection Hysteresis)

Page17


Cell Selection Process

There are two kinds of cell selection

Stored list cell selection

Normal cell selection

In fact, the process might be different for different

MSs

Page18


Stored List Cell Selection

Page19

Come into idle mode

Is it a BCCH carrier?

Right PLMN&C1>0& priority is not prohibited ?

Try the frequencies in the BA list of the stored frequency one by one

YES

Search BCCH frequency which has

been stored

Decode SCH, read cell para. on BCCH

YES

Try all the frequencies stored?

No

No

Normal Cell Selection

No


Normal Cell Selection

Page20

Search all frequency

Rank according to receiving level

Come into idle mode

Is it a BCCH carrier?

Right PLMN&C1>0& priority is Normal ?

Select the next frequency with the higher Rx_level

YES No

YES

Try the cell of other PLMN allowed in the SIM card

Stay in a cell(RX-LEV is strongest, C1>0 , cell priority is not prohibited) without

considering the PLMN

All frequency not satisfy

No

YES

Emergency call mode

Select the frequency with the highest Rx_level

Decode SCH, read cell para. on BCCH

No

All frequency not satisfy

No

No YES

Right PLMN&C1>0& priority is Low ?


PLMN Selection Parameter

CGI=MCC+MNC+LAC+CI

Once MS receives SYS INFO, it decodes the CGI

information, and decides whether it can stay in the cell

according to the MCC and MNC indicated by CGI.

At the same time, it judges whether the current location

area is changed, so as to decide whether to execute

location update. During the location update process, MS

will report the new LAI to the network, so that the network

can know the LA in which MS is currently located.

Page21


Cell Selection ParameterC1 indicates the path loss criterion of cell selection.

C1 of the serving cell must be greater than 0. It is calculated as follows:

C1 = RXLEV - RXLEV_ACCESS_MIN - MAX((MS_TXPWR_MAX_CCH - P), 0)

In the case of a DCS1800 class 3 MS, C1 is calculated as follows:

C1 = RXLEV - RXLEV_ACCESS_MIN - MAX((MS_TXPWR_MAX_CCH +

POWER_OFFSET - P), 0)

Page22

• RXLEV indicates the average receive level of the MS• RXLEV_ACCESS_MIN indicates the minimum receive level required for the MS to access the network.• MS_TXPWR_MAX_CCH indicates the maximum transmit power allowed for the MS to access the network. • POWER_OFFSET indicates PWRDIV of the MS.• P indicates the maximum output power of the MS.


RXLEV_ACCESS_MIN

Parameter ID: RXMIN

Value Range: 0~63 (-110 dBm ~ -47 dBm)

Default Value: 8

Description: Minimum received signal level of the

MS. This parameter specifies the minimum receive

level of an MS to access the BSS. For details. see

GSM Rec. 05.08.

Page23

MML: SET GCELLBASICPARA


MS_TXPWR_MAX_CCH

Parameter ID: FMSMAXOPCC

Value Range: 0~19

Unit: level

Default Value: 5 (900MHz cell),0 (1800/1900MHz cell)

Description: This parameter determines the maximum

transmit power level of the MS when it begins to access

a cell and has not yet received power control command.

Page24

MML: SET GCELLCCCH


CBA (Cell Bar Access)

Parameter ID: CBA

Value Range: No, Yes

Default Value: No

Description: Cell_Bar_Access, worked together with CBQ

to set the priority status of the cell in idle mode for cell

selection and reselection.

Page26

MML: SET GCELLIDLEBASIC


CBQ (Cell Bar Qualify)

Parameter ID: CBQ

Value Range: No, Yes

Default Value: No

Description: Cell_Bar_Qualify. CBQ only affects the cell

selection, but is not related to cell reselection. It works

with CBA to define the access priorities of cells.

Page27



Application of CBA and CBQ

Page28



Page29

The traffic of cell A and B is heavy. Set these two cells with CBA=“Yes”, CBQ=“No”.

A B



Page30

B is a micro cell. Set B to “Normal” and A to “Low”.

BA


Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page31


Cell Reselection

Under certain condition, MS will select a neighbor

cell as its new serving cell, this procedure is called

cell reselection.

The possible neighbor cells’ information in idle mode

are held in BA1 table, which will be broadcasted to MS

via BCCH.

Those for dedicated mode ones are held in BA2 table,

which will be broadcasted to MS via SACCH.

Page32


Normal Neighbor Cells

Page33

Theoretical Neighbor Cells Actual Neighbor Cells

B

CA

D

B

CA

D


Special Neighbor Cells

Page34

B

C

A

A


Forced Cell Reselection

Forced cell reselection will be triggered under the follow conditions:

Current serving cell is prohibited

Down link of serving cell fails: DSC=0

C1 is less than 0 continuously for 5s

The access times exceed the value of parameter MSMAXRETRAN

Page35


Normal Cell Reselection

When there is no abnormal situation happened, MS will trigger normal cell reselection as described below:

Cell reselection for cells in the same location area If the C2 value of the target cell is higher than that of the

serving cell for longer than 5 seconds, a cell reselection process will be performed and the MS tunes to the new cell.

Cell reselection for cells in different location areas If the C2 value of the target cell is higher than that of the

serving cell by at least the value of CRH for longer than 5 seconds, a location update process and the cell reselection process will be performed.

Page36


Cell Reselection Parameter

Page37

C2=C1+CRO-TO*H(PT-T) When PT is not equal to 31

C2=C1-CRO When PT is equal to 31

For neighbor cell:

H(PT-T)=0, when PT-T<0

H(PT-T)=1, when PT-T ≥ 0

For serving cell:

H(PT-T) = 0


CRO(Cell Reselect Offset) Parameter ID: CRO

Value Range: 0~63( the corresponding level value:

0~126dB, stepped every 2dB).

Unit: 2dB

Default Value: 0

Description: Cell Reselect Offset. It is a parameter in C2

calculation to give an intentional modification in MS cell

reselection.

Page38



TO(Cell Reselect Temporary Offset)

Parameter ID: TO

Value Range: 0~7 (the corresponding value is 0~60dB, 7

corresponds to “Infinite”).

Default Value: 0

Description: Cell Reselect Temporary Offset. It is a

parameter in C2 criterion to give a temporary modification

within PT time.

Page39

MML: SET GCELLIDLEAD


PT(Cell Reselect Penalty Time)

Parameter ID: PT

Value Range: 0~30(the corresponding time is 20~620s), 31(reserved for changing the effect of CRO on C2)

Unit: Second

Default Value: 0

Description: Cell Reselect Penalty Time. It is used to ensure the safety and validity of cell reselection because it helps to avoid frequent cell reselection.

Page40

MML: SET GCELLIDLEAD


PI(Cell Reselect Parameters Indication)

Parameter ID: PI

Value Range: Yes , No

Default Value: Yes

Description: Cell Reselect Parameters Indication (PI), sent

on the broadcast channel, indicates whether "Cell

Reselect Offset (CRO)", "Cell Reselect Temporary Offset

(TO)" in the "SET GCELLIDLEAD" command, and "Cell

Reselect Penalty Time (PT)" are used.

Page41



CRH(Cell Reselect Hysteresis)

Parameter ID: CRH

Value Range: 0~14, the step size is 2dB

Unit: dB

Default Value: 6

Description: Cell Reselection Hysteresis. It is the

parameter used when cell reselection happens between

two location areas.

Page42


Copyright © 2011 Huawei Technologies Co., Ltd. All rights reserved. Page43

Question

One MS is switched on. The parameters of the MS and cells

shown on the next slide.

Other given conditions:

Rx_Lev_Access_Min = 8 (-102 dBm)

MS_TXPWR_MAX_CCH=5 (for every cell)

Please give the answers for following questions:

Which cells will be selected after the MS is powered on ?

Which cell will be selected after cell reselect (suppose the current

serving cell is H)?

Cell Select and Reselct Answers.rar


Question1800MHZRXLev= -66dBmCBA=No, CBQ=NoPI=YesPT=1CRO=6MCC=460CRH=6dBTO=6MNC=01

900MHZRXLev= -58dBmCBA=No, CBQ=NoPI=YesPT=0CRO=5MCC=460CRH=4dBTO=7MNC=99

B

CH 900MHZ

RXLev= -65dBmCBA=No, CBQ=NoPI=NoPT=0CRO=2MCC=460CRH=12dBTO=6MNC=011800MHZ

RXLev= -78dBmCBA=No, CBQ=NoPI=YesPT=0CRO=4MCC=460CRH=4dBTO=6MNC=01

G

F900MHZRXLev= -62dBmCBA=Yes, CBQ=YesPI=YesPT=0CRO=3MCC=460CRH=6dBTO=6MNC=01

E

900MHZRXLev= -64dBmCBA=Yes, CBQ=YesPI=NoPT=1CRO=0MCC=460CRH=6dBTO=6MNC=01

D

1800MHZRXLev= -75dBmCBA=No, CBQ=NoPI=YesPT=1CRO=10MCC=460CRH=0dBTO=6MNC=01

Dual Band

IMSI 460010000032093

MSA

900MHZRXLev= -59dBmCBA=No, CBQ=YesPI=YesPT=0CRO=10MCC=460CRH=6dBTO=7MNC=01

LAC border


Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page45


Definition of Location UpdateInform the system the LA (Location Area) where the MS is located.

Normal location update

Period location update

Attach

Page46

LA 1

LA 2


Period of Periodic Location Update(T3212)

Parameter ID: T3212

Value Range: 0~255

Unit: 6 minutes

Default Value: 20

Description: It is the Periodic Location Update Timer. It

defines the interval of periodic location update.

Page47



Procedure of Periodic Location Update

Page48

BSC

MSC

MS

1 Hour

1 Hour 1 Hour

++ ++ +

reset reset reset


Abnormal Occasion

Page49

LA 3

LA 2

LA 1

But I am always powered on

The subscriber you dialed has been powered off


Reason1 of Abnormal Occasion

Page50

BSC

MSC

MS

1 Hour

1 Hour

1 Hour



Page51

BSC

MSC

MS

1 Hour

1 Hour

1 Hour



Page52

Even if T3212 setting is less than the system (MSC) query time, the system

will still sometimes voice “The subscriber you dialed is powered off”.

A B

T3212=4 T3212=8

LAC

“Ping-pong Reselect”


ATT (Attach-detach Allowed)

Parameter ID: ATT

Value Range: Yes, No

Default Value ： Yes

Description: It is Attach-detach allowed. It is used to

inform MS whether IMSI attach-detach is allowed in this

cell. If it is set to “Yes”, the network will not process the

connection to the called mobile subscriber when MS is

power-off. Thus network processing time and radio

resources are saved. Otherwise the network will process

the connection even though the MS has been powered

off.

Page53



Abnormal Occasions What will happen if MS is powered off in a cell with “ATT=yes” and then

powered on in a new cell with “ATT=no” in the same LAC?

Then what will happen if MS is powered on in a cell with “ATT=yes” and then powered off in a cell with “ATT=no” in the same LAC?

What will happen if the two cells belong to different LAC?

Page54

Powered off

ATT=yes ATT=no

LAC

Powered on


Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page55


Paging Resources

Paging messages are delivered on PCH channel which

belongs to CCCH, then how many CCCH and PCH channels

are configured? How about the paging performance?

Page56

PCH RACHAGCH

Downlink CCCH Uplink CCCH

NCH


Paging Resources

What kind of CCCH channels are configured?

Decided by parameter: CCCH Conf

How many CCCH blocks are used for PCH in one 51 multi-

frame?

Decided by parameter: BSAGBLKSRES (CCCH Blocks Reserved for

AGCH)

How many 51 multi-frame is one paging cycle?

Decided by parameter: BS_PA_MFRMS

How does the MS know which PCH block belongs to it?

Calculated by CCCH grouping and IMSI of MS

Page57


CCCH Conf Value Range: 1 Compounding CCCH , 1 Non-Compounding

CCCH, 2 Non-Compounding CCCHs, 3 Non-compounding

CCCHs, 4 Non-compounding CCCHs.

Default Value: When there is one TRX in the cell, one

combined CCCH is recommended (in a system with few paging

messages in location area). For others, it is configured

according to the number of TRX in the cell.

Description: It is Common Control Channel Configuration.

CCCH configuration determines the capacity of PCH, AGCH

and RACH. This parameter can be automatically configured by

system according to the TRX channel configuration.

Location: This parameter depend on channel configuration

Page58



BSAGBLKSRES (CCCH Blocks Reserved for AGCH)

Parameter ID: BSAGBLKSRES

Value Range: 0~7 (Non-Compounding CCCHs), 0~2 (1

combined CCCH)

Unit: Block

Default Value: 2 (Non-combined CCCH), 1(1 combined CCCH)

Description: BS-AG-BLKS-RES, indicating the number of the

CCCH message blocks reserved for the AGCH. After the

CCCHs are configured, the value of this parameter indicates

the actual seizure rates of the AGCHs and the PCHs over the

CCCHs.

Page59



BSPAMFRAMS (Multi-Frames in a Cycle on the Paging CH)

Parameter ID: BSPAMFRAMS

Value Range: 2~9

Unit: Multi-frame period (51 frames)

Default Value: 2 Multi-frame period

Description: It is Paging Channel Multi-frames. It defines

the number of multi-frames used as a cycle of paging

sub-channels.

Page60



Example of Paging Group

PCH10....

PCH10

1

2

9

10

The

First

Paging

period

8

AGCH AGCH

PCH56

16PCH56

AGCH AGCH

AGCH AGCH

AGCH AGCH

AGCH AGCH

AGCH AGCH

BS_PA_MFRAMES= 8 Multi-frame period (51 frames)

.

.

.

.

.

.

.

.

BS_AG_BLKS_RES=2

8 Multi-

frame

form

one

period

（ PCH N—the Nth paging channel）

PCH1

PCH1

1 Non-Compounding CCCH

.

.

.

.

.

.

.

.

The

second

Paging

period

MSA MS B MS C


Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other Parameters

Page62


Overview of Network Access Network access is a relay procedure for MS from idle

mode to dedicated mode.

Normal reasons of network access include:

Originated call setup

Paging response

Location update

SMS

Network access of MS will be controlled by system with

the help of some parameters which will be introduced

detailed later.

Page63


Random Access of MS

Below show us the procedure of MS’ random access to

network

Page64

0

500BCCH TS

Uplink

Subcriber push button at this moment to setup a call

R

50 016171819

RRRR RRRR RRRR RRR RRRR R R RR RRRR RR RRRR RR R R RR R RR

The MS possibly send the access burst at this moment, why?

if no response, the MS will retry again certain seconds later, How long? And how many times of retry maximal?

Time

R


TX-integer

Parameter ID: TX

Value Range: 3~12, 14, 16, 20, 25, 32, 50

Unit: RACH Timeslot (equals to a TDMA frame, 4.615ms)

Default Value: 32

Description: Used to calculate the number of timeslots in

the interval between multiple channel requests sent by

MS.

Page65



Calculation of S

Page66

STX-integer

Non-Combined CCCH Combined CCCH

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


Max Retransmissions for Radio Priority 1, 2, 3, 4

Parameter ID:MAXRETRANS1, MAXRETRANS2,

MAXRETRANS3, MAXRETRANS4

Value Range: 1, 2, 4, 7

Unit: Time(s)

Default Value: 7 Times

Description: MAX Retransmissions is the upper limit of

times that MS is allowed to send “Channel Request” in one

immediate assignment procedure.

Page67


Max Retransmissions for Radio Priority 1, 2, 3, 4

Maximum retransmission for radio priority 1, 2 … 4. The

2bit Radio Priority message carried by the MS in the

Packet Channel Request message has four levels of

priorities. Level 1 is the highest priority, and level 4 is

the lowest priority.

Page68

MML: SET GCELLPRACH


Common Access Control Class

Parameter ID: COMMACC

Value Range: Level 0~9 Forbidden

Default Value: 0000000000

Description: One of the parameters of random access control

information. It is used for load control of ordinary

subscribers, to permit or forbid the network access of some

common level users. “1” stands for forbidden and “0” for

permitted.

Page69

MML: SET GCELLCCBASIC


Special Access Control Class

Parameter ID: SPECACC

Value Range: Level 11~15 Forbidden


Description: It is used for load control, permitting or

forbidding the network access of some special level users.

“1” stands for forbidden and “0” for permitted.

Page70



Emergent Call Disable

Parameter ID: ERGCALLDIS


Default Value: No

Description: Emergence Call Disable. When EC Disable is

set to “No”, it means emergency call is permitted.

Otherwise it is prohibited.

Page71



Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other Parameters

Page72


CS RACH Min. Access Level Parameter ID: RACHACCLEV

Value Range: -121~-104

Unit: dBm

Default Value: -109

Description: The parameter affects the access of MS. This parameter specifies the level threshold for the random access of the MS. If the receive level of the RACH burst in the CS domain is smaller than the value of CS RACH Min.Access Level, the BTS regards this access as an invalid one and no decoding is performed. If the receive level of the RACH burst is greater than the value of CS RACH Min. Access Level, the BTS considers that an access request exists on this timeslot, and determines together with the value of "Random Access Error Threshold" whether the RACH access is valid.

Page73

MML: SET GCELLCCACCESS


PS RACH Min. Access Level Parameter ID: PSRACHACCLEV

Value Range: -121~-104

Unit: dBm

Default Value: -109

Description: The parameter affects access to the packet service. This parameter specifies the level threshold for the random access of the MS. If the receive level of the RACH burst in the PS domain is smaller than the value of PS RACH Min.Access Level, the BTS regards this access as an invalid one and no decoding is performed. If the receive level of the RACH burst is greater than the value of PS RACH Min. Access Level, the BTS considers that an access request exists on this timeslot, and determines together with the value of "Random Access Error Threshold" whether the RACH access is valid.

Page74

MML: SET GCELLCCACCESS


ECSC (Early Classmark Sending Control) Parameter ID: ECSC


Default Value: No

Description: Early Classmark Sending Control. It indicates if an MS

in the cell is allowed to use early Classmark sending.

Yes: The MS reports Classmark3 to the network immediately

after link setup.

No: The MS is forbidden to report its Classmark3 to network

initiatively.

Page75



Definition of Classmark In GSM system, the abilities that MS supports, such as service

ability, band ability, power ability, encryption ability, is described

by the classmark. BSC decodes the information according to the

requirement of network and transfer to the network.

There are 3 kinds of

classmark:Classmark1 、 Classmark2 、 Classmark3.

Network knows about abilities of MS either via inquiring for MS’s

CLASSMARK or via requiring MS to report CLASSMARK3

immediately by itself after link setup.

Page76


Classmark Update Flow

For dual-band MS, after the SCCP

connection is established and

before receiving message "CM

Service Accepted" there will be a

class mark update flow.

CR message reports the

information of Classmrk 2. And in

the class mark update flow, MS will

report Classmark 3 information

which is related to the dual-band

capability.

Page77

Classmark Change

Classmark Enquiry

MS BSS MSC

Classmark Request

Classmark Update


Information about Classmark 2/3

Page78


TCH Immediate Assignment

Parameter ID: IMMASSEN


Default Value : No

Description: Whether to allow immediate TCH assignment.

If this parameter is set to YES, the BSC can assign a TCH

immediately when there is no available SDCCH for a

channel request. If this parameter is set to NO, the BSC

can assign only an SDCCH when processing a channel

access request.

Page79



Immediate Assignment Optimization Parameter ID: IMMASSCBB


Default Value : No

Description: The channel activation and immediate assignment

messages are sent at the same time to reduce the signaling

processing time, thus increasing the response speed of the

network. This parameter is mainly used for satellite transmission,

i.e., to reduce the impact of satellite transmission delay. Yes: when the Transmission Mode of the BTS is Satellite transmission

No: when the Transmission Mode of the BTS is Terrestrial transmission

Page80



Signaling Flow of Immediate Assignment Optimization

Page81

MS BTS BSC MSC

Channel_req Channel_Required

Channel_Active

Channel_Active_Ack

IMMEDIATE ASSIGN COMMAND

Establish_IND (CM Service Req)

CR(Complete_L3_information)

CM Service Accepted

CC

(NOTE 1)

First SABM

UA

…

CHAN_ACT

MS BTS BSC

IMM_ASS_CMD

CHAN_ACT_ACK


Directed Retry

In TCH assignment process, if there is no TCH available,

handover can take place instead of assignment, and this

is called direct retry.

Huawei improves directed retry on two sides:

Traffic

Receive level

Page82


Directed Retry ProcedureStart

[Directed Retry] is enabled?

[Assignment Cell Load Judge Enable]

is enabled?

Load of the current cell [Cell Directed

Retry Forbidden Threshold](s)?

Yes

No

No

No

Yes

YesLoad of the

neighbor cell ≤ [Directed Retry Load Access Threshold](n)?

RXLEV(n) >RXLEV (s) + [Inter-cell HO Hysteresis](s->n)

- [Direct Retry Handover Level Range](s->n) ?

Yes

End: Trigger directed retry

No

Yes

No

End: Assignment failure

Traffic

Rxlevel


Directed Retry Parameter Setting


See notes

Page85


Directed Retry Parameter Setting


Radio Link Timeout

Parameter ID: RLT

Value Range: 4~64, the step size is 4

Unit: SACCH period (480ms)

Default Value: 52

Description: This parameter is used for MS to decide

downlink disconnection in case of SACCH decoding failures.

Page87



Application of Radio Link Timeout

Page88

Impact of radio link timeout

A BP Q

Poor coverage


Radio Link Timeout

To increase the robustness of the SACCH channel, to improve

the AMR network coverage performance, and to lower the call

drop rate, in practice the AMR FR/HR RLT should be set higher.

Page89

Normal Call Radio Link Timeout (SACCH

period(480ms))

AMR FR AFR Radio Link Timeout (SACCH period(480ms))

AMR

HR AHR Radio Link Timeout (SACCH period(480ms))

Default

Value

52

Call Type Parameter

64

52


SACCH Multi-Frames Parameter ID: SAMULFRM

Value Range: 0~63

Unit: SACCH period (480ms)

Default Value: 32

Description: It is a timer used to determine whether the uplink radio link connection fails. BSS judges the uplink radio link failure according to uplink SACCH BER.

Every time BTS fails to decode the MR sent from MS, this timer decreases by 1;

Every time BTS succeeds to decode the MR, this timer increases by 2.

When this timer reaches 0, BTS judges that the uplink radio connection fails, then BTS sends a radio connection failure message to BSC.

This parameter and the radio link timeout (RLT) are used to judge the uplink/downlink radio connection failure.

Page90



SACCH Multi-Frames

To increase the robustness of the SACCH channel, to improve the

AMR network coverage performance, and to lower the call drop

rate, in practice the AMR FR/HR SACCH Multi-Frames should be

set higher.

Page91

Normal Call SACCH Multi-Frames (SACCH

period(480ms))

AMR FR AFR SACCH Multi-Frames (SACCH period(480ms))

AMR

HR

AHR SACCH Multi-Frames (SACCH

period(480ms))

Default

Value

32

Call Type Parameter

64

52


T200 Parameter ID: T200

Value Range: 60~2400 (step: 10)

Unit: ms

Default Value: 12

Description: T200 timer (LAPD protocol) is used to avoid deadlock during data transfer on the data link layer. The value of the timer indicates the time when the LAPD link waits for the response or acknowledgement frame after sending the command frame.

On the LAPDm layer, every time a message is sent, the opposite end is requested to acknowledge the reception. If this message is lost for unknown reasons, it will occur that both ends keep waiting, leading to system deadlock.

Therefore, a timer should be started when the sender sends a message. If the timer times out, the sender will regard that the receiver has not received the message and will resend the message.

Page92

MML: SET BTSRINGATTR


N200 Parameter ID: N200

Value Range: 1~3

Unit: none

Default Value: 3

Description: the value of this parameter specifies the maximum number of times when a frame is retransmitted (LAPD protocol)

Different timer values should be set for different LAPDm channels such as SDCCH, FACCH and SACCH. This is because these channels have different transmission rate.

Page93

MML: SET BTSRINGATTR


Use LAPDm N200

Parameter ID: N200PARASWITCH

Range: On, Off

Default Value : Off

Description: Whether the BSC sends the LAPDm N200

parameter to the BTS. If this parameter is set to YES, the

BSC sends the LAPDm N200 parameter. If this parameter

is set to NO, the BSC does not send the LAPDm N200

parameter.

Page94

MML: SET GCELLCCTMR


Call Re-establishment Forbidden

Parameter ID: CALLRESTABDIS


Default Value: Yes

Description: Informing MS whether call

reestablishment is allowed or not.

Page95



Network Identity Parameter — BSIC BSIC=NCC+BCC

In GSM system, each BTS is allocated with a color code,

which is called BSIC. MS can identify two cells with the same

BCCH by the help of BSIC.

In network planning, make sure that BCCH of neighbor cells

are different from the serving cell’s BCCH to reduce the

interference.

Practically it is still possible that a same BCCH is re-used in

the surrounding cells. For cells using the same BCCH in a

relevant near distance, their BSIC must be different so that

MS can identify two neighbor cells with same BCCH.

Page96


NCC Permitted

Parameter ID: NCCPERMIT

Value Range: Selection of 0~7 Perm.


Description: Network Color Code. It lists NCC that need be

measured by MS. If a neighbor cell’s NCC is permitted, MS

will report MRs of it to the network.

Page97



MBR (Multi-Band Report)

Parameter ID: MBR

Value Range: 0~3

Default Value: 0

Description: Multi-Band Report is used for requesting the

MS to report the measurement information of neighboring

cells in multiple frequency bands. This parameter is carried

in the system information 2ter and 5ter.

Page98



Application of MBR

Page99

-92dBm -82dBmA B

C -68dBm

D -90dBm

E -78dBm

F -88dBm

G -96dBm

H -84dBm

GSM1800

GSM900

S


Max Resend Times of Phy. Info. Parameter ID: MAXRESEND

Range Value :1~255

Unit: Times

Default Value :30

Description: Maximum times for a Physical Information

message to be transmitted. When the retransmission times

exceeds this parameter and the BTS still cannot receive any

correct SAMB frame from the MS, the BTS sends a connection

failure message (including the handover failure information) to

the BSC, which releases the assigned channel and stops timer

T3105 after receiving this message.

Page100

MML: SET GCELLHOAD


T3105

Parameter ID: T3105

Range Value : 0~255

Unit: 10ms

Default Value : 7

Description: When BTS sends physical information to the MS, the BTS starts the timer T3105. If the timer T3105 times out before receive the SABM frame from MS, BTS re-sends physical information to MS and restarts the timer T3105.

Page101

MML: SET GCELLHOAD


Intra-BSC Handover Signaling Flow

Page102

MS BTS1 BSC BTS2 MS MSC

Channel_Active

Channel_Active_Ack

Measure Report from MS

HANDOVER COMMAND

Handover AccessHandover_Detect

PHYINFO

PHYINFO

First SABM

Establish_IND

HANDOVER COMPLETE

Handover_Performed

UA


PWRC

Parameter ID: CANPC

Value range: Yes, No.

Default Value: Yes

Description: It is used to indicate MS whether to delete received

level value obtained from the timeslots of BCCH when MS

measures receiving level during base band hopping mode.

When it is set to “No”, it means the influence of receiving level on BCCH

is in consideration.

If it is set to “Yes”, process it in the way mentioned above.

Page103

MML: SET GCELLCCCH


Cell Extension Type

Parameter ID: EXTTP

Value Range: Normal cell, DoubleTS Ext cell

Default Value: Normal cell, but the configuration is

according to the practical situation.

Description: It indicates whether a cell is an extended

cell and the extended cell mode.

Page104

MML: ADD GCELLMML: MOD GCELL


Max TA (Maximum Time Advance)

Parameter ID: MAXTA

Value Range:

0~63 (Normal cell)

0~255 (Double TS Ext cell)

Unit: Bit period (1 bit = 0.55km)

Description: this parameter determines the actual coverage area of BTS. When BTS receives the channel request message, it determines whether channel assignment should take place in the current cell by comparing the TA with the value of this parameter.

Page105


Default Value

62 for normal cell

219 for dual TS extended cell


Interference Band Threshold 0~5 Parameter ID: INTERFTHRES 0~5

Value Range: 110~85

Unit: -dBm

Default Values

110 ( Interference band threshold 0)


98 ( Interference band threshold 2 )




Description: It decides the corresponding value for each interference band (from band 1 to band 5) and used to measure the uplink interference during the SDCCH/TCH(F)/TCH(H) timeslot is in idle mode.

Page106

MML: SET GCELLOTHEXT


Interference Calculation Period Parameter ID: INTERPERIOD

Value range: 1~31

Unit: SACCH period (480 ms)

Default Values: 20

Description: Before the BTS transmits the radio resource indication message to the BSC, the interference levels measured on idle channels in the period defined by this parameter are averaged. The average interference level is used to classify the interference levels on idle channels into five interference bands. A too big value of this parameter cannot reflect the change of interference. A too small value of this parameter wastes the resources.

Page107

MML: SET GCELLOTHEXT


UL DTX

Parameter ID: FRULDTX (full rate), HRULDTX (half rate)

Value Range: May use, Shall use, Shall not use

Default Value: Shall use

Description: It is used to indicate whether MS uses DTX

function. It shows the DTX state of the MS in the previous

measurement period.

Page108



DL DTX Parameter ID: FRDLDTX (full rate), HRDLDTX (half rate)

Value range: Yes, No

Default Value: Yes

Description: This parameter indicates whether downlink DTX

is used in a cell. The use of downlink DTX is also controlled

by the DTX switch in the MSC. If downlink DTX is forbidden in

the MSC, downlink DTX is not used regardless of the setting

of this parameter. If downlink DTX is allowed in the MSC, the

setting of this parameter can determine whether downlink

DTX is used in the cell.

Page109


Thank youwww.huawei.com

2- omo133000 bsc6900 gsm v9r13 ms behaviors in idle mode issue 1.00

Documents

radio link

forced cell

sys info 5bis

call drop

location update

rach control

rach control

dual band