83181560-2-Omo133000-Bsc6900-Gsm-v9r13-Ms-Behaviors-in-Idle-Mode-Issue-1-00

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

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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.

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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.

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Contents1. System Information Reception

2. Cell Selection3. Cell Reselection4. Location Update5. Paging Processing6. Access Processing7. Other parameters

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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

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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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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 RACH Control Parameter

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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)

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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)

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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 RACH Control Parameter

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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 RACH Control Parameter CBCH Channel Description (optional) CBCH Mobile Allocation (optional) SI4 Rest Octets (parameters related to cell reselection)

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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

Neighbor Cell Description

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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)

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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

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Contents1. System Information Reception2. Cell Selection

3. Cell Reselection4. Location Update5. Paging Processing6. Access Processing7. Other parameters

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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)

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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

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Stored List Cell Selection

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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

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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.

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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)

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• 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.

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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.

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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.

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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.

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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


Contents1. System Information Reception2. Cell Selection3. Cell Reselection

4. Location Update5. Paging Processing6. Access Processing7. 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.

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Normal Neighbor Cells

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Theoretical Neighbor Cells Actual Neighbor Cells

BCA

D

B

CA

D


Special Neighbor Cells

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BC

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

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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

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.

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Cell Reselection Parameter

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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.

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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.

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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.

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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.

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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.

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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 BandIMSI 460010000032093

MSA

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

LAC border


Contents1. System Information Reception2. Cell Selection3. Cell Reselection4. Location Update

5. Paging Processing6. Access Processing7. Other parameters

Page45


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

Normal location updatePeriod location updateAttach

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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.

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Procedure of Periodic Location Update

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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

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BSC

MSC

MS

1 Hour

1 Hour

1 Hour



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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.

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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


Contents1. System Information Reception2. Cell Selection3. Cell Reselection4. Location Update5. Paging Processing

6. Access Processing7. 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?

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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

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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

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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



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

Pagingperiod

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 Pagingperiod

MSA MS B MS C


Contents1. System Information Reception2. Cell Selection3. Cell Reselection4. Location Update5. Paging Processing6. Access Processing

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

0500BCCH

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.

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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.

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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 Default Value: 00000 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.

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Emergent Call Disable Parameter ID: ERGCALLDIS Value Range: Yes, No 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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Contents1. System Information Reception2. Cell Selection3. Cell Reselection4. Location Update5. Paging Processing6. Access Processing7. 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 Value Range: Yes, No 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.

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 Value Range: Yes, No 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 Value Range: Yes, No 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

NoYes

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 Value Range: Yes, No 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. Default Value: 11111111 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

PHYINFOPHYINFO

First SABM

Establish_IND

HANDOVER COMPLETEHandover_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) 105 ( Interference band threshold 1) 98 ( Interference band threshold 2 ) 92 ( Interference band threshold 3 ) 87 ( Interference band threshold 4 ) 85 ( Interference band threshold 5)

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


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83181560-2-Omo133000-Bsc6900-Gsm-v9r13-Ms-Behaviors-in-Idle-Mode-Issue-1-00

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