2 omf010001 system information issue1.6

8/4/2019 2 OMF010001 System Information ISSUE1.6

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HUAWEI TECHNOLOGIES CO., LTD.

All rights reserved

www.huawei.com

Internal

System Information


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HUAWEI TECHNOLOGIES CO., LTD. Page 2All rights reserved

Chapter 1Chapt

er 1 System Information OverviewSy

stem Information Overview

Chapter 2Chapter 2 Parameters IntroductionParameters Introduction

Chapter 3Chapter 3 Case StudyCase Study


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System Information Overview

System information (SYS INFO) contains network parameters sent

to MS through Um interface

network identity parameters (CGI, CID)

cell selection parameterssystem control parameters

network function parameters

System information can be sent through two kinds of logical

channelsSystem information on BCCH (IN the IDLE mode)

System information on SACCH (Dedicated mode)


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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)


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SYS INFO 1 - Control Parameter

These control parameters include:

Maximum re-transmitting times (MAX retrans)

Extended transmission timeslots (Tx_integer)

Common access control level (AC)

Call reestablish permitted (RE)

Emergency call permitted (EC)


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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 cells BCCH

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



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SYS INFO 2BIS

SYS INFO 2BIS

2BIS contains RACH control data and neighbor cells 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)


8/86HUAWEI TECHNOLOGIES CO., LTD. Page 8All rights reserved

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)


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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



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Cell Identity and Location Area Identity

Cell Global Identity (CGI) consists of Location Area Identity

(LAI) and Cell Identity (CI). And LAI includes Mobile Country

Code (MCC), Mobile Network Code (MNC), and Location Area

Code (LAC). SYS INFO 3, 6, and 4 contain all or part of theinformation of CGI. According to the received SYS INFO, MS

decodes the CGI, and decide whether it can register in the

network based on the MCC and MNC indicated by CGI. At the

same time, it can judge whether the current location area is

changed, so as to decide whether it is necessary to start thelocation updating process.


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Control Channel Description

Control channel description includes the following parameters

IMSI Attach-Detach Allowed (ATT)

Common Control Channel Configuration (CCCH_CONF)

Access Granted Blocks Reserved (BS_AG_BLKS_RES)

Paging Channel Multi-frames (BS_PA_MFRAMES)

Periodic Location Update Timer (T3212)


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Cell Option

Cell option contains the following parameters:

Power control indication (PWRC)

Discontinuous transmission (DTX)

Radio link timeout


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Cell selection parameters indicate how the MS should behave

after the MS is powered on. It includes the following

parameters:

Cell Reselection Hysteresis (CRH)

Maximum power level of control channel

(MS_TXPWR_MAX_CCH)

Minimum receiving level of MS permitted to access

(RXLEV_ACCESS_MIN)

Additional reselection parameter indicator (ACS)

Half-rate supported (Support Half-Rate)


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SYS INFO 4

It consists LAI, RACH control parameters, cell selectionparameters and optional CBCH channel information. It istransmitted on BCCH. When the cell supports cell broadcastfunction, CBCH together with CBCH MA describe the

configuration of CBCH the relevant frequency information. Content

SYS INFO 4

LAI



CBCH Channel Description (optional)

CBCH Mobile Allocation

SI4 Rest Octets (parameters related to cell reselection)

SYS INFO 4


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CBCH Channel Description and CBCH MA

These two parameters are optional. When system supports

cell broadcast, CBCH Channel Description explains the CBCH

channel configuration situation. When CBCH Channel is in

frequency hopping mode, CBCH MA is also needed.


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SI4 Rest Octets

It contains the following parameters:

Cell Reselection Parameter Indicator (PI)

Cell Bar Qualify (CBQ)

Cell Bar Access (CBA)

Cell Reselect Offset (CRO)

Temporary Offset (TO)

Penalty Time (PT)


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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


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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



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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 cells.

Content

SYS INFO 5TER

Neighbor Cell Description (Extended)


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SYS INFO 6

SYS INFO 6

It describes LAI, cell identity, and some parameters

describing the cells 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


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Chapter 1Chapter 1 System Information OverviewSystem Information Overview


Chapter 3Chapter 3

Case StudyCase Study


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Introduction to SYS INFO Parameters

Huawei GSM System Information Parameters:

Network Identity Parameters

System Control Parameters

Cell Selection Parameters

Network Functional Parameters


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Network Identity Parameter CGI

Network identity parameters mainly include cell global identity

(CGI) and base station identity code (BSIC).

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 thenetwork can know the LA in which MS is currently located.


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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, effort should be

made to make sure that BCCH of neighbor cells are different

from the serving cells 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.


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Mobile Country CodeMCC

Definition

MCC consists of 3 decimal numbers. It indicates the home

country of the mobile subscriber.

Format

MCC is composed of 3 decimal numbers. The coding range

is decimal 000-999.


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Mobile Network CodeMNC

Definition

MNC is used to uniquely identify a specific GSM PLMN

network in a certain country (decided by MCC).

Format

MNC is composed of two decimal numbers. The coding

range is decimal 00-99.


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Location Area Code LAC

Definition

To locate the location of MS, the whole area covered by

each GSM PLMN is divided into different location areas.

LAC is used to identify different location areas.

Format

LAI contains LAC, which is composed of two bytes. LAC

adopts hexadecimal coding. The available range is from

0001H to FFFEH. The code 0000H and FFFFH cannot be

used (please refer to specification GSM0303, 0408, and1111). One location area can contain one or more cells.


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Cell Identity CI

Definition

To uniquely identify each cell in the GSM PLMN, the network

operator needs to allocate one code for each cell, which is the

cell identity (CI). Cell identity, together with LAI, is used for

identity of each cell in the world. (specification 0303).

Format

CI is composed of 16 bits, The available range is from 0 to

65535.


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Network Color Code NCC

Definition

NCC is a part of BSIC. MS uses it to distinguish adjacent

BTS that belong to different GSM PLMN.

Format

NCC is composed of 3 bits, with the range of 0 to 7.


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BTS Color Code BCC

Definition

BCC is a part of BSIC. For its function, please refer to above

sections.

Format

BCC is composed of 3 bits. The available range is from 0 to 7.


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System Control Parameters

ATT

CCCH_CONF

BS_AG_BLKS_RES

BS_PAMFRAMES T3212

Radio Link Timeout


NCC Allowed

MS MAX Retrans

TX-Integer

Common Access Control Class MBR

ECSC

heck it it means that once we power off it system does not consider it in the next paging signals othe


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ATT

Value range: Yes, No

Content 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.

Recommendation Yes

heck it, it means that once we power off it system does not consider it in the next paging signals othe

ered off and u moved to cell B and then powered on in cell B but the ATT box was not checked so th

r off and out of coverage message until you make a call (System will wake up) and u are powered on


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CCCH_CONF

Value range: 1 Non-Compounding CCCH, 1 Compounding

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

CCCHs, 4 Non-compounding CCCHs.

Content: It is Common Control Channel Configuration. CCCH

configuration determines the capacity of PCH, AGCH and

RACH. This parameter can be automatically configured by the

BSC Data Auto Configuration System according to the TRX

channel configuration.

Recommendation: 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.

mpounding CCCH (BCCCH is alone in the time slot, compounding (both BCCH and SDCCH together

Extended BCCH for Paging on the expense of TCH only TS 2, 4, and 6 can be co


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BS_AG_BLKS_RES

Value range: 0~2 (1 combined CCCH), 0~7 (others)

Unit: Block

Content: It is also called Access Granted Blocks Reserved. It is

the number of CCCH channel message blocks that are reserved

in one multi-frame for access granted channels (AGCH).

Recommendation: 2 (non-combined CCCH)

See note


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BS_PA_MFRAMES

Value range: 2 9

Unit: Multi-frame period (51 frames)

Content: It is Paging Channel Multi-frames. It defines the

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

channels.

Recommendation: 2

Combine two multiframes in one paging cycle so instead of having 7 PCH u have 14 PCH


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Application of T3212

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. ((Taxi Drivers MS))

A B

T3212=4 T3212=8

LAC

Ping-pong Reselect


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Radio Link Timeout

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

Unit: SACCH period (480ms)

Content: This parameter is used for MS to decide down-link

disconnection in case of SACCH decoding failures.

Recommendation: 20~56

Check the downlink qualityfor the dedicated mode

-Call drop responsible

Check the downlink qualityfor the dedicated mode

-Call drop responsible

1 Measure Report: 4 SACCH TDMA frames: 15 0r26*8 TS* 26 TCH-frames*4 SACCH = 480 ms=

0.55 Sec (The length of the Measurement report

1 Measure Report: 4 SACCH TDMA frames: 15 0r26*8 TS* 26 TCH-frames*4 SACCH = 480 ms=

0.55 Sec (The length of the Measurement report


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Application of Radio Link Timeout (RLT)

cell level command

Impact of radio link timeout

A B

P Q

Poor coverage

For example RLT here is set to 4 (within 2seconds level is 0) and you need to spend 55

seconds in the poor coverage area call will drop,if the RTL is 40 u will not drop

But sometimes you will keep the call withhorrible quality

For example RLT here is set to 4 (within 2seconds level is 0) and you need to spend 55

seconds in the poor coverage area call will drop,if the RTL is 40 u will not drop

But sometimes you will keep the call withhorrible quality


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There are table BA1 and table BA2.

Table BA1 describes BCCH frequencies of the adjacent cells to

be measured when the MS is in idle mode.

Table BA2 describes BCCH frequencies of the adjacent cells to

be measured when the MS is in dedicated mode.


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Theoretical Neighbor Cells Actual Neighbor Cells

B

CA

D

B

CA

D

Application of Neighbor Cell Description


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B

C

A

A

Application of Neighbor Cell Description


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NCC Allowed

Value range: Check box, including options 0~7.

Content: Network Color Code, sent in system information 2

and 6. It lists NCC that need be measured by MS. If a neighbor

cells NCC is permitted, MS will report MRs of it to the network.

Recommendation: Subject to the concrete conditions.

NCC=0

.

.

.

.NCC=7

NCC=0

.

.

.

.NCC=7

If the NCC is not checked so you cannot makeHO but u can reselect, some operators do not

check it to keep u forced on the same operator

If the NCC is not checked so you cannot makeHO but u can reselect, some operators do not

check it to keep u forced on the same operator

How many time you send theRACH

How many time you send theRACH


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MS MAX Retrans

Value range: 1, 2, 4, 7 times

Unit: Time

Content: It is one of the random access control parameters. MS MAX

Retrans is the upper limit of times that MS is allowed to send Channel

Request in one immediate assignment procedure.

Recommendation:

Set to 7 for areas with low traffic (suburban or rural area) and the

cell radius more than 3 km.

Set to 4 for areas with ordinary traffic (non-busy area in the city)

and the cell radius is less than 3km.Set to 2 for micro-cell

Set to 1 for micro-cell with heavy traffic or with obvious congestion.

Set to 4 or 7 for satellite transmission BTS.

Access burst is so short because we still do notknow the TA

Access burst is so short because we still do notknow the TA

RACHRACH

B

T

S

B

T

S


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TX-Integer (T)

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

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

Content: Used to calculate the number of timeslots in the interval

between multiple channel requests sent by MS.

Recommendation: 20 (If the cell immediate assignment success rate

is low, set the S with a larger value. Select 32 for satellite

transmission, so as to reduce satellite transmission delay).

To avoid more than one MS asking for the AGCHat same time, randomly the MSs will ask for the

RACH within 20 time slots

To avoid more than one MS asking for the AGCHat same time, randomly the MSs will ask for the

RACH within 20 time slots


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Calculation of S (Waiting time)

ST

Combined CCCH Non-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

S: should not be big, except in case of

satellite transmission other wise we will

have SDCCH congestion

S: should not be big, except in case of

satellite transmission other wise we will

have SDCCH congestion

Because we have

less BCCH

channels time is

longer than main

CCCH

Because we have

less BCCH

channels time is

longer than main

CCCH


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Common Access Control Class

Value range: Check box, including level 0 forbidden,lever 1

forbidden,, till level 9 forbidden

Content: 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. 1stands for forbidden and 0 for permitted.

Recommendation: 0000000000


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Special Access Control Class

Value range: Check box, including level 11 forbidden,level12

forbidden,, till level 15 forbidden

Content: 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.

Recommendation: 00000


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MBR

Value range: 0~3

Content: Multi-band Reporting. It is used to inform MS to report

the adjacent cells in a controllable way. It is sent in the System

Information 2ter and 5ter.

In the Measurement report you can report 1 serving cell and upto 6 highest

Neighbouring cells

MBR=0: not considering the top 6 cells belong to which band

MBR=1: 900:1, 1800:1; remained cells (4 neighbours) will be same serving band

neighbouring cells

MBR=2: 900:2, 1800:2; remained (2 neighbours) cells will be same serving band

neighbouring cells

In the Measurement report you can report 1 serving cell and upto 6 highest

Neighbouring cells

MBR=0: not considering the top 6 cells belong to which band

MBR=1: 900:1, 1800:1; remained cells (4 neighbours) will be same serving band

neighbouring cells

MBR=2: 900:2, 1800:2; remained (2 neighbours) cells will be same serving band

neighbouring cells

Best cells:


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Application of MBR (Usually not used in load balance)

- dBm- dBm

AB

C - dBm

D - dBm

E - dBm

F - dBm

G - dBm

H - dBm

GSM

GSMS

Best cells:

C

E

B

H

F

D

A

G


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ECSC


Content: Early Classmark Sending Control. It indicates if an

MS in the cell is allowed to use early Classmark sending. See

Protocol 0408.

Recommendation: No, if the MSC is Huawei product (by

default MSC will ask about it), and Recommendation is yes if

the MSC is not Huawei.

My dual band ability (power, etc)


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CBQ (Cell Bar Qualify)

CBA (Cell Bar Access)

MS_TXPWR_MAX_CCH

RXLEV_ACCESS_MIN

PI (Cell Reselect Parameters Indication)

CRO (Cell Reselection Offset)

TO (Temporary Offset)

PT (Penalty Time)CRH ( Cell Reselection Hysteresis)


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Cell Selection Process

There are two kinds of cell selection.

Normal cell selection (you have to search all available freq.)

Stored list cell selection (Search Some freq.)

In fact, the process might be different for different MSs


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Stored List Cell Selection

Search the BCCH

which have been

stored

Can not find it

Normal cell

selection

Can find it

Can reside in it

Cant reside ,search

neighbor cell (BA1)

Come into

idle mode

NO

YES


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Normal Cell Selection

Search all frequency

Rank according to receiving level

Come into idle

mode

Check whether this is a BCCH carrier, get

SCH and decode system information

PLMN, C1>0, priority is normal

YES

Check next one

NO

NO

YES


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Normal Cell Selection

Check the next frequency by the same step

Check the cell which priority is low (i.e. lower power,

C1>0,PLMN

Come into idle

modeTry the cell which PLMN is allowed

in the SIM card

Stay at a cell which RX-LEV is strongest,

C1>0 , cell priority is not prohibitedEmergency call

mode (112)

NO

NO

YES

YES

YES

NO

YES

Rx-Access-Min: 8 = -102 dBm

Scale: 0 = 120 1= 110 etc

Rx-Access-Min: 8 = -102 dBm

Scale: 0 = 120 1= 110 etc


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Cell Selection Parameterto control the coverage

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

RLA_C: Receiving level of MS

RXLEV_ACCESS_MIN: Minimum receiving level of MS permitted to access

P: maximum Physical supported transmitting power of MS.

Scale: 0 = -120, 1=-110 etc

If we want the coverage to be less so we

increase this parameter to a higher value as

10 = -100 dB (so users with signal below this

value will not be able to access the NT)

Scale: 0 = -120, 1=-110 etc

If we want the coverage to be less so we

increase this parameter to a higher value as

10 = -100 dB (so users with signal below this

value will not be able to access the NT)

MS UL Configured power in theBSC in access burst

MS UL Configured power in theBSC in access burst


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CBQ

Value range: Yes , No

Unit: None

Content: Cell Bar Qualify. CBQ only affects the selection of cells but

is not related to cell reselection. It works with CBA to define the

access priorities of cells.

Recommendation: No.

In the Cell selection after PLMN, and C1, then

Priority and it is controlled by two parameters: CBQ

& CBA

Check the notes

In the Cell selection after PLMN, and C1, then

Priority and it is controlled by two parameters: CBQ

& CBA

Check the notes


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CBA


Content: Cell Bar Access, worked together with CBQ to set the

priority status of the cell in idle mode for cell selection and

reselection.

Recommendation: Yes


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Application of CBQ

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

CBA=No, CBQ=No.

A B


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Application of CBA

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

B

A


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Application of CBA

CBQ(A) = NO CBA(A) = NO

A

C

B

D


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MS TXPWR_MAX_CCH

Value range: 0~31

Unit: level

Content: This parameter determines the maximum allowed

output power of the MS when it begins to access a cell and has

not yet received power control command.

Recommendation: 5(900MHz), 0(1800MHz)


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RXLEV_ACCESS_MIN

Value range: 0~63

Unit: Level

Content: It means the minimum receive signal level required

for MS to access a cell.

Recommendation: 8


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Cell Reselection Process

Cell reselection for cells in 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.

Two consecutive cell reselections caused by C2 have a time interval of 15

seconds. In other words to say, if because of C2 a MS reselected to a cell, then

the MS cannot reselect to another cell by the cause of C2 within 15 seconds.

If current serving cell is prohibited, or down link fails, or C1 is less than 0

continuously for 5s, cell reselection will also be triggered.

MS starts a cell reselection if the access times exceed the MAX retrans.


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Cell Reselection Parameter

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

C2=C1-CRO When PT is equal to 31

Function H(x)=0, when x0

For serving cell TO*H(PT-T) = 0For serving cell TO*H(PT-T) = 0

T: is a timer, measures how long -in seconds-the

neighbouring cell remains in the best 6

neighboring cells and it is inside the step

function H(x)

After some time (in seconds you are trusted and

always acting as my neighbour , the H(x)=0

(when PT-T=0) and at this time no more penalty

for you (PT) because it is a trusted neighbour

T: is a timer, measures how long -in seconds-the

neighbouring cell remains in the best 6

neighboring cells and it is inside the step

function H(x)

After some time (in seconds you are trusted and

always acting as my neighbour , the H(x)=0

(when PT-T=0) and at this time no more penalty

for you (PT) because it is a trusted neighbour


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PI

Value range: Yes (1), No (0).

Unit: None

Content: Cell Reselect Parameters Indication, sent on the

broadcast channel of the cell. It is an indication to the

existence of Cell Reselect Offset(CRO), Temporary

Offset(TO) and Penalty Time(PT).

Recommendation: Yes.

If we do not check the PI this means C2 = C1If we do not check the PI this means C2 = C1


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CRO

Value range: 0~63, the corresponding level value: 0~126dB,

stepped every 2dB.

Unit: None

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

calculation to give an intentional modification in MS cell

reselection.

Recommendation: 0

F i ll TO*H(PT T) 0


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TO

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

corresponds to Infinite.

Unit: None

Content: Cell Reselect Temporary Offset. It is a parameter in

C2 criterion to give a temporary modification within PT time.

Recommendation: 0

For serving cell TO*H(PT-T) = 0

TO:1 = 10 dB

For serving cell TO*H(PT-T) = 0

TO:1 = 10 dB

You will punish the neighbouring cell for PT

You will punish the neighbouring cell for PT


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PT

Value range: 0~31, the corresponding time is 20~620s. 31 is to

change the formula of C2.

Unit: None

Content: Cell Reselect Penalty Time.

Recommendation: 0

p g g

period

PT:0 = 20 Seconds

p g g

period

PT:0 = 20 Seconds


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CRH

Value range: 0~14 , the step size is 2

Unit: dB

Content: Cell Reselection Hysteresis. It is the parameter used

when cell reselection happens between two location areas.

Recommendation: 4

To avoid so many ReselectionTo avoid so many Reselection


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Network Function Parameter

PWRC (Power Control Permitted)

UL DTX (Uplink Discontinuous Transmission)

Call Re-establishment Allowed (RE)

EC Allowed (Emergency Call Allowed)


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PWRC

Value range: Yes, No.

Unit: None

Content: It is used to indicate MS weather to reduce 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 not in consideration. If it is set to Yes, process it

in the way mentioned above.

Recommendation: Yes


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If the call drop while moving from an area to

If the call drop while moving from an area to


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Call Re-establishment Allowed


Unit: None

Content: Informing MS whether call reestablishment is allowed

or not.

Recommendation: No

another MS will automatically reestablish and it

is different from the redial in case of busy

another MS will automatically reestablish and it

is different from the redial in case of busy


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EC Allowed


Unit: None

Content: Emergence Call Allowed . When EC Allowed is set to

Yes, it means emergency call is permitted. Otherwise it is

prohibited.

Recommendation: Yes.


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Others in Data Configuration System

System Information Usage

Regular Transmission

Regular Transmission Interval


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System Information Usage

Value Range: It is a check box, including system information

1~12, 2bis, 2ter, 5bis, 5ter, 10bis.

Unit: None

Content: It is used to determine whether a type of system

information should be sent. A selected box means to send.

Recommendation: Select system information 1~6, 2bis, 2ter,

5bis, 5ter


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Regular Transmission


Unit: None

Content: It shows whether BSC chooses to update system

information contents transmitted by BTS. If it is Yes, BSC will

send system information to BTS at a certain interval (it is

decided by Regular Transmission Interval). Otherwise,

system information can only be updated manually by using

BSC maintenance system.

Recommendation: Yes


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Regular Transmission Interval

Value range: 0~255

Unit: Minute

Content: It stipulates the time interval that BSC updates

system information to BTS.

Recommendation: 10 minutes


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Chapter 1Chapter 1 System Information OverviewSystem Information Overview


Chapter 3Chapter 3 Case StudyCase Study


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Case Study

Case Description

During the process of optimization in a certain area, it is

found out that the signal is poor in a certain section of

suburban highway. The signal strength measured is less

than -95dBm. Handling Procedure

Modify the data in BSC. Add neighbor relationship to Cell A

and B for each other. The coverage problem is thus solved.

Case 1: Island effect

C

B

A-92

-80

-95

Case Study

Case 2: Incorrect CGI causes MS unable to register on the network


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Case description

The subscriber complained that MS could not register to the

network, or it was difficult to register to the network between

BTS A and B, or no network mark was displayed on the MS, but

MS indicated that the signal was very good. Some subscribers

also complained that MS could make MTC could not make

MOC.

Note: If you configure it wrongly you can receive a call because it is coming

thru the Paging siganl and eventhough the reselection is BSC level not MSC

level so even if your Cell CGI is wrongly configured you can camp on it andreceive a call but not originate a call because originating requires MSC

pathway and u have wrong cell CGI

Cause analysis

CGI of the cell was modified. So the network register flow was

not normal. Although the signal was very good, MS could not get

registered in the network.

Recommendation and summary

CGI is a very important parameter and should be configured

correctly, thus to ensured that the CGI data in BSC and MSC

are the same.

Case 2: Incorrect CGI causes MS unable to register on the network.


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Case Study

Case description

Subscribers complain that the signal fluctuates in a certain area. On-site

test shows that this phenomenon does exist. From the testing mobile,

we can see that there are a lot of cells signals in this area. Some

frequencies are the suburb BTS signals far away from this area. The cell

reselection of MS is rather frequent.

Handling procedure

Modify parameter RXLEV_ACCESS_MIN of all cells in urban area and

make them consistent with each other. The problem of signal fluctuation

is solved.

Recommendation and summary

In area with complicated coverage, the RXLEV_ACCESS_MIN of each

cell should be kept same.

Case 3: RXLEV_ACCESS_MIN causes signal fluctuation.


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Case description

A local GSM network has more than 6000 subscribers. There are four

BTSs. The network has been working properly. But from sometime on,

some MS often lost connection with network suddenly. The complaintfrom subscribers in urban area increased.

Handling procedure

Modify T3212 to 10, i.e. 60 minutes. Modify the corresponding time of

MSC to 180 minutes. Two days observation shows no subscriber

complaint and the problem is solved.

Case 4 Too small T3212 causes MS lose connection with network.

Case Study


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Thank You

2 omf010001 system information issue1.6

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