Bsc6900 Gsm v9r11r12r13 Ms Behaviors in Idle Mode Issue1.03 - Omo133000

www.huawei.com

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

47pt

30pt

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LT Medium

: Arial

47pt

黑体

28pt

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细黑体

GSM MS Behaviors in

Idle Mode


35pt

32pt

) :18pt

Foreword

Once the MS is powered on and the mobile network is existed, the MS

will be either in idle mode or dedicated mode.

When the MS is in idle mode, there is no dedicated connection with

network, but the MS is still controlled by the parameters and functions

in the system.

The MS behaviors in idle mode is including:

System information reception

Cell selection and reselection

Location update

Paging processing

Access processing.

There are some other parameters to be introduced which is related

with the future processing of network access.

Page2


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32pt

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Objectives

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

Describes 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


35pt

32pt

) :18pt

Contents

1. System Information Reception

2. Cell Selection

3. Cell Reselection

4. Location Update

5. Paging Processing

6. Access Processing

7. Other parameters

Page4


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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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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


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Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page16


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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


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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


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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


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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 ?


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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


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Cell Selection Parameter C1 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.


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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


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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


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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


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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



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Application of CBA and CBQ

CBA CBQ Cell Selection

Priority Cell Reselection

Priority

No No Normal Normal

Yes No Forbidden Forbidden

No Yes Low Normal

Yes Yes Low Normal

Page28


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Page29

The traffic of cell A and B is heavy. Set these two cells with

CBA=“Yes”, CBQ=“No”.

A B


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Page30

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

B

A


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Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page31


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Cell Reselection

Under certain condition, MS will select a neighbor cell as

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.

For dedicated mode, neighbor cells information are held in

BA2 table, which will be broadcasted to MS via SACCH.

Page32


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Normal Neighbor Cells

Page33

Theoretical Neighbor Cells Actual Neighbor Cells

B

C A

D

B

C A

D


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Special Neighbor Cells

Page34

B

C

A

A


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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


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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

C2(n)> C2(s) for 5 Seconds

Cell reselection for cells in different location areas

C2(n) > C2(s) + CRH for 5 seconds

Page36


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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


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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



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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


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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


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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



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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



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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)?


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Page44

1800MHZ

RXLev= -66dBm

CBA=No, CBQ=No

PI=Yes

PT=1

CRO=6

MCC=460

CRH=6dB

TO=6

MNC=01

900MHZ

RXLev= -58dBm

CBA=No, CBQ=No

PI=Yes

PT=0

CRO=5

MCC=460

CRH=4dB

TO=7

MNC=99

B

C H 900MHZ

RXLev= -65dBm

CBA=No, CBQ=No

PI=No

PT=0

CRO=2

MCC=460

CRH=12dB

TO=6

MNC=01 1800MHZ

RXLev= -78dBm

CBA=No, CBQ=No

PI=Yes

PT=0

CRO=4

MCC=460

CRH=4dB

TO=6

MNC=01

G

F 900MHZ

RXLev= -62dBm

CBA=Yes, CBQ=Yes

PI=Yes

PT=0

CRO=3

MCC=460

CRH=6dB

TO=6

MNC=01

E

900MHZ

RXLev= -64dBm

CBA=Yes, CBQ=Yes

PI=No

PT=1

CRO=0

MCC=460

CRH=6dB

TO=6

MNC=01

D

1800MHZ

RXLev= -75dBm

CBA=No, CBQ=No

PI=Yes

PT=1

CRO=10

MCC=460

CRH=0dB

TO=6

MNC=01

Dual Band

IMSI 460010000032093

MS A

900MHZ

RXLev= -59dBm

CBA=No, CBQ=Yes

PI=Yes

PT=0

CRO=10

MCC=460

CRH=6dB

TO=7

MNC=01

LAC border

Question


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Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page45


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Definition of Location Update

Inform the system the LA (Location Area) where the MS is located.

Normal location update

Period location update

Attach

Page46

LA 1

LA 2


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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.

Page48



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Procedure of Periodic Location Update

Page49

BSC

MSC

MS

1 Hour 1 Hour 1 Hour

+ + + + +

reset reset reset


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Abnormal Occasion

Page50

LA 3

LA 2

LA 1

But I am always

powered on

The subscriber

you dialed has

been powered

off


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Case 1 of Abnormal Occasion

Page51

BSC

MSC

MS

1

Hour

1

Hour

1 Hour


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Case 2 of Abnormal Occasion

Page52

BSC

MSC

MS

1 Hour 1

Hour

1

Hour


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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



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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


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Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other parameters

Page55


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Paging Resources

Paging messages are delivered on PCH channel which

belongs to CCCH.

How many CCCH and PCH channels are configured? How

about the paging performance?

Page56

PCH RACH AGCH

Downlink CCCH Uplink CCCH

NCH


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Paging Resources

How many 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 long the period for one paging cycle in term of 51 multi-

frame?

Decided by parameter: BS_PA_MFRMS

How does the MS know which PCH block for monitoring?

Calculated by CCCH grouping and IMSI of MS

Page57


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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



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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



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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



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Page61

Example of Paging Group

PCH10

.

.

.

.

PCH10

1

2

9

10

The

First

Paging

period

8

AGCH AGCH

PCH56

16 PCH56

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


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Paging Coordination

Paging coordination

Send CS paging message by SGSN

Page62

BSS CS Core Network

A

PS Core Network

PCU

BSS NSS

Gb

Gs


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BSS Paging Coordination

BSS Paging Coordination

Send CS paging message by PACCH when MS is in packet

transfer mode.

Page63

BSS CS Core Network

A

PS Core Network

PCU

BSS NSS

Gb


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Data Configuration

Page64


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Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other Parameters

Page65


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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.

Page66


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Random Access of MS

Below show us the procedure of MS’ random access to

network

Page67

0

50 0 BCCH

TS

Uplink

Subscriber presses the

call button at this

moment to initiate a

call setup

R

50 0 16 17 18 19

R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R

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


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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.

Page68



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Calculation of S

Page69

S TX-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


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MS Max Retransmissions

Parameter ID:MSMAXRETRAN

Value Range: 1, 2, 4, 7

Unit: Time(s)

Default Value: 4 Times

Description: MAX Retransmissions is the upper limit of times

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

assignment procedure.

Page70

MML: SET GCELLCCBASIC


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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.

Page71

MML: SET GCELLCCACCESS


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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.

Page72

MML: SET GCELLCCACCESS


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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.

Page73



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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.

Page74



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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.

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Contents


2. Cell Selection

3. Cell Reselection

4. Location Update



7. Other Parameters

Page76


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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.

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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.

Page78


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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.

Page79

Classmark Change

Classmark Enquiry

MS BSS MSC

Classmark Request

Classmark Update


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Information about Classmark 2/3

Page80


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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.

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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

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Signaling Flow of Immediate

Assignment Optimization

Page83

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


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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

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Page85

Directed Retry Procedure(Used in HOI) Start

Directed Retry] is enabled?

[Assignment

Cell Load Judge Enable]

is enabled?

Load of the

current cell [Cell Directed

Retry Forbidden Threshold](s)?

Yes

No

Yes

No

Yes

Yes

Load of the

neighbor cell ≤ [Directed Retry Load

Access Threshold](n)?

RXLEV(n) >=

[Min Power Level For Directed Retry] (s)?

Yes

End: Trigger directed retry

No

Yes

No

End

Traffic

Rxlevel

Assignment，preemption，

queuing

No

Load of the

current cell 100%?

No

Assignme

nt，preemptio

n，queuing

End

No


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Page86

Directed Retry Procedure(Used in HOII) Start

[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

Yes

Load of the

neighbor cell ≤ [Load handover Load

Accept 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

Assignment，preemption，

queuing

Traffic

Rxlevel

End

Assignmen

t，preemptio

n，

queuing

No

Load of the

current cell 100%?

Yes

End


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Page87

Directed Retry Parameter Setting


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See notes

Page88


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Page89

Directed Retry Parameter Setting


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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.

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Application of Radio Link Timeout

Page91

Impact of radio link timeout

A B

P Q

Poor coverage


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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.

Page92

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


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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.

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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.

Page94

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


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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.

Page95

MML: SET BTSRINGATTR


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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.

Page96

MML: SET BTSRINGATTR


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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.

Page97

MML: SET GCELLCCTMR


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Call Re-establishment Forbidden

Parameter ID: CALLRESTABDIS


Default Value: Yes

Description: Informing MS whether call reestablishment is

allowed or not.

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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.

Page99


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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.

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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.

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Application of MBR

Page102

-92dBm -82dBm A B

C -68dBm

D -90dBm

E -78dBm

F -88dBm

G -96dBm

H -84dBm

GSM1800

GSM900

S


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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.

Page103

MML: SET GCELLHOAD


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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.

Page104

MML: SET GCELLHOAD


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Intra-BSC Handover Signaling Flow

Page105

MS BTS1 BSC BTS2 MS MSC

Channel_Active

Channel_Active_Ack

Measure Report from MS

HANDOVER COMMAND

Handover Access Handover_Detect

PHYINFO

PHYINFO

First SABM

Establish_IND

HANDOVER COMPLETE

Handover_Performed

UA


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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.

Page106

MML: SET GCELLCCCH


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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.

Page107

MML: ADD GCELL

MML: MOD GCELL


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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.

Page108


Default Value

62 for normal cell

219 for dual TS extended cell


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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.

Page109

MML: SET GCELLOTHEXT


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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.

Page110

MML: SET GCELLOTHEXT


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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.

Page111



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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.

Page112


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Bsc6900 Gsm v9r11r12r13 Ms Behaviors in Idle Mode Issue1.03 - Omo133000