07-CDMA2000 Paging Optimization Guide

CDMA2000 1X Paging Optimization Guide Internal open

2004-10-26 All rights reserved Page i of pages 43

Document No. Product Name

Applicable for Wireless network planning Dept.

Product version

Drafted by CDMA Network Planning Dept.

Document version

CDMA2000 1X Paging Optimization

Guide

Huawei Technologies Co., Ltd.

All rights reserved

Table of Contents

1 About this Document ................................................................................................................. 3

1.1 Overview ...............................................................................................................................3

1.2 Contents ...............................................................................................................................3

2 Basic Knowledge ....................................................................................................................... 4

2.1 PCH Features .......................................................................................................................4

2.1.1 PCH Structure ............................................................................................................4

2.1.2 PCH Message ............................................................................................................6

2.1.3 MS Working Mode .....................................................................................................7

2.1.4 Fast Paging Channel .................................................................................................7

2.2 Call Flow ...............................................................................................................................8

3 Extended Bounary Paging Solution .......................................................................................... 9

3.1 Background ..........................................................................................................................9

3.2 Implementation Principle and Solutions ...........................................................................9

3.2.1 Concepts ....................................................................................................................9

3.2.2 Extended Bounary Paging Solution with a Cooperation Between MSC and BSC........................................................................................................................................... 10

3.2.3 Intra-BSC Extended Bounary Paging Solution ................................................... 12

3.2.3.1 Extended Bounary Paging Solution True LAC-based .......................... 13

3.2.3.2 Extended Bounary Paging Solution Idle Handoff-based ..................... 13

3.3 Application Background .................................................................................................. 13

3.3.1 Extended Bounary Paging Solution with a Cooperation Between MSC and BSC........................................................................................................................................... 14

3.3.2 Intra-BSC Extended Bounary Paging Solution ................................................... 16

3.4 Data Configuration ........................................................................................................... 16

3.4.1 MSC Data Configuration ........................................................................................ 16

3.4.2 BSC Data Configuration ........................................................................................ 17

3.5 Precautions ....................................................................................................................... 20

4 Optimization of BSC and BTS Paging Algorithm .................................................................... 20

4.1 Purpose .............................................................................................................................. 20

4.2 Implementation Solution .................................................................................................. 21

4.2.1 Cooperation Mechanism between BSC and BTS ............................................... 21

4.2.2 BTS Paging Scheduling Mechanism .................................................................... 23

4.2.3 GPM Combination Function .................................................................................. 24

4.3 Paging Measurement Index and Analysis ...................................................................... 26

4.4 Parameter Configurations ................................................................................................ 29

4.4.1 Default Value of F-CSCH Message Resending Parameter ................................. 29

4.4.2 Resending Times and Living Time of Paging Channel Message ...................... 31

4.4.3 L2 Acknowledgement Parameters for Access Channel Message .................... 35

4.4.4 Parameter and Function Verification ................................................................... 36

5 Application Cases .................................................................................................................... 39

Key words:

Paging channel, paging message, extended bounary paging, extended LAC,

paging algorithm, scheduling mechanism and paging measurement index.

Abstract:

This guide details the following:

The knowledge related to CDMA paging, including paging channel

message, Mobile Station (MS) working mode and call flow.

The background and implementation principle of extended bounary paging

solution cooperating with an application solution.

The data configuration and precautions during the actual application.

The VC03 paging optimization algorithm, cooperation mechanism with

BSC and BTS involved, BTS scheduling mechanism and GPM

combination strategy.

The new paging measurement indices.

Solutions to analyze the indices.

Abbreviations list:

Abbreviation Full name AC Authentication Center BCCH Broadcast Control Channel BS Base Station BSC Base Station Controller BTS Base Transceiver System CAM Channel Assignment Message CDMA Code Division Multiple Access CCM Call Control Module CI Cell Identifier DBM Data Burst Message DCH Dedicated Channel

ECAM Extended Channel Assignment Message

ESN Electronic Serial Number

ESPM Extended System Parameter Message

FCCH Forward Common Control Channel F-CSCH Forward Common Signaling

Channel

F-DSCH Forward Dedicated Signaling Channel

GPM General Paging Message GPR General Paging Response HLR Home Location Register

IMSI International Mobile Subscriber Identity

ISPAGE Inter-system Paging LAC Location Area Code LAC Layer Link Access Control Layer LAI Location Area Identifier MIN Mobile Identification Number MS Mobile Station MSC Mobility Switch Center SPU Signal Process Unit OM Order Message PCH Paging Channel RAND Random Variable SCI Syn-Capusle Indicator SIM Subscriber Identifier Module SSD Shared Secret Data TCH Traffic Channel VLR Visitor Location Register

Reference list:

1. Tan guanzhong, Huawei Technologies Co., Ltd., CBSCV100R003C03 LAC

Resending Mechanism Design Specifications.

2. Kyoung II Kim, Posts & Telecom Press, CDMA Design and Optimization..

1 About this Document

1.1 Overview

This guide details the following:

The knowledge related to CDMA paging, call flow, and BSS flow control.

The background and implementation principle of extended bounary paging

solution cooperating with an application solution.

The data configuration and precautions during the actual application.

The VC03 paging optimization algorithm, cooperation mechanism with BSC

and BTS involved, and BTS scheduling mechanism.

The new paging measurement indices.

Solutions to the problems in the actual network, the relation and analysis with

paging measurement indices.

The readers should have general knowledge about CDMA. The learner can read

the first chapters, and the last two can be a reference and guide for the skilled during

the actual network application.

1.2 Contents

CDMA20001X Paging Optimization Guide includes five parts. For details, see

the following table.

Chapter Title Content

1 About the document Introducing the contents of the document

2 Basic knowledge

Introducing paging channel features, including paging channel message and MS working mode.

Listing specific call flow so that the reader has an overall understanding about paging channel

3 Extended bounary paging solution

Introducing the background, solved problems, and application.

Detailing implementation solution and data configuration so that the

reader can understand and use the solution.

4 Optimization of BSC and BTS paging algorithm

Introducing the purpose of BSC and BTS algorithm optimization.

Detailing the cooperation mechanism and scheduling mechanism and specific measures (such as GPM combination).

Describing the new paging measurement indices in the VC03.

Providing the solutions to analyze the indices.

Providing parameter configuration during the application.

5 Application case The obtained typical cases based on actual application.

6 Annex Providing BTS.ini file in the VC03 Describing new parameters of

VC03.

2 Basic Knowledge

2.1 PCH Features

The FCCH of the CDMA 2000 1X includes pilot channel, syn. Channel and paging

channel, but the RCCH includes access channel. Wherein, dedicated WALSH code is

allocated for each FCCH. The WALSH code corresponding to paging channel ranges

from 1 to 7, and the rates of paging channel include 9600bps and 4800bps based on

the protocol. If there are no special descriptions, the rate is 9600bps. If power control

does not exist in the FCCH, a correlation must exist between the gain configurations.

For details, see CDMA2000 1X Network Planning Parameter Configuration Guide. To

support new traffic type in the subsequent protocol version, such new common

channels as FCCCH and BCCH are added to implement the function similar to paging

channel. No more descriptions are required here.

2.1.1 PCH Structure

Figure 1 PCH Structure

Maximum paging channel slot cycle

163.84s

2048 slots

Paging channel slot 0 ¡ Paging channel slot 2047Paging channel slot n

80ms

…

Paging channel half-frame Paging channel half-frame Paging channel half-frame

8 paging channel half-frames

10ms

SCI…

=1

… … …

… ..

SCI SCIPaging channelhalf-frame body

Paging channel

Half-frame body

Paging channel

Half-frame body=0 =1

Paging channel

message body

paging channel

message body

MSG_LENGTH Message body CRC

Fill inPaging channel message

8bits 30bits

0~7bits8*MSG_LENGTH

paging channel message body

Paging channel

message

Follow former

asynchronization message

Synchronization body

bits

……

Figure 1

Maximum paging channel slot cycle

163.84s

2048 slots

Paging channel slot 0 ¡ Paging channel slot 2047Paging channel slot n

80ms

…

Paging channel half-frame Paging channel half-frame Paging channel half-frame

8 paging channel half-frames

10ms

SCI…

=1

… … …

… ..

SCI SCIPaging channelhalf-frame body

Paging channel

Half-frame body

Paging channel

Half-frame body=0 =1

Paging channel

message body

paging channel

message body

MSG_LENGTH Message body CRC

Fill inPaging channel message

8bits 30bits

0~7bits8*MSG_LENGTH

paging channel message body

Paging channel

message

Follow former

asynchronization message

Synchronization body

bits

……

Figure 1

To know the paging channel, we should have a brief understanding about PCH

structure first. For details, see figure 1.

The PCH is divided into paging slots of 80ms, and each paging slot is

composed of 8 half-frames, and each half-frame is 10ms. Each half-frame starts from

Syn-Capsule Indicator (SCI) bit, and the first new message in the paging slot must

follow SCI bit. At that time, set SCI bit to 1.

PCH message is transferred on the PCH body. The PCH body includes message

body, indicating 8bit field of the whole channel body length and 30bit CRC. The lengths

of such messages as General Page Message (GPM), Channel Assignment Message

(CAM), or Order Message (OM) on the channel range from 100 to 150bit. One paging

slot includes 760bit (8 half-frames, each half-frame has 95 valid load bit, and others

are SCI bit), so it can send multiple GPMs, CAMs or OMs.

Most message body occupies one half-frame and a part of the second half-frame,

so the message body to be synchronized will waste another part of the second

half-frame. To enhance the utilization of this PCH, it is allowed only to synchronize the

first new message body within one paging slot and the subsequent message body

within the slot is attached at the back of former message body. The message filed

length of the message body indicates the start position of next message body in the

slot.

If the message body is less than 8bit from SCI bit to the end, the next message in

the slot must be synchronized. Therefore, SCI of next message must be 1 (if the

synchronization is required, set SCI to 1). The length of PCH message body must be

the integer times of byte. If not, fill in it with 0-7bit.

If multiple PCHs are constituted and alternated periodically, a slot cycle is

generated. The shortest slot cycle includes 16 slots, with the maximum length of 2048

slots. The length (T) of specific slot cycle is related to the setting of Slot_Cycle_Index

i. The relation is as follows: T=16×0.08×2i , wherein, i ranges from 0 to 11 (select 0 or

1in general).

2.1.2 PCH Message

In the CDMA system, the PCH sends the message from BS to MS and bearers

many messages, including call processing (voice and data), supplementary service

(short message), null GPM, serving redirection message, and feature notification

message. The null GPM refers to the message that does not include MS information,

indicating that all the messages in the slot are sent through the setting of related field.

In this case, MS remains more power. The messages related to calling processing

include the following:

Overhead Message or General Message: Including the information required

by the call setup, and it is updated periodically to ensure the successful call

setup. It is required to send the message once at least 1.28s, such as system

parameter message, access parameter message, neighbour list message,

CDMA channel list message and extended system parameter message.

Paging Message (GPM): Used to originate a paging to MS. When receiving call

request from MS, MSC sends a paging request message. MSC sends paging

request message through cell mode and LAC mode.

CAM/ECAM and OM: Used to exchange information with MS to complete the

call setup. BS sends the message only in a cell during the call setup.

Short Message Center (SMC) sends the SM through MSC and Data Burst

Message (DBM) of air interface from BSC to BTS. The SM can be sent through many

modes. The specific modes are set in MSC, and no more descriptions are required

here. For details, see CDMA1X Location Area Planning Guide.

2.1.3 MS Working Mode

Paging channel is divided into several slots, so slotted and unslotted working

modes are available when MS is in IDLE state.

Slotted mode: MS is awaked periodically in a special slot cycle to check the

paging message pointing at this MS. When MS works in slotted mode, it is

allowed to lower the power until pre-specified slot occurs. MS and MSC adopt

HASH function and takes MS MIN (the last 10 digits of IMSI) as the function

variable to judge when to awake the MS. At that time, the system can

determine the correct slot and performs a paging to MS through the slotted

mode. After sending all the messages on the slot, the system sends a

“–DONE” (that is, null GPM). Therefore, when MS works in slotted mode, it

does not receive the whole paging channel slot in case of being awaked. But

the MS is allowed to leave the slot to be IDLE sate.

Non-slotted mode: When MS is in IDLE state, it monitors all the paging slots,

and receives the messages on the paging slot. Obviously, when MS is

working in unslotted mode, this MS consumes the battery power too much.

Therefore, MS works in slotted mode in general. But some MSs can modify

the working mode.

2.1.4 Fast Paging Channel

To better save MS battery effectively, another channel related to the paging---fast

paging channel is added to the protocol. The rates also include 9600 and 4800bps,

and the corresponding WALSH code is 16. To save forward power, the rate of fast

paging channel should be 4800bps, and the difference between its gain and pilot‟s is

2– -5dB. The fast paging channel requires that MS should support this function, so it is

optional. Only two types of information bit are sent on the fast paging channel: Paging

indication bit and configuration change indication bit. They are sent repeatedly. At that

time, the MS working mode is consistent with that only paging channel is available.

MS monitors the fast paging channel of a special slot. If receiving the bit information

pointing at fast paging channel of this MS, MS monitors paging channel to receive the

message. When MS is in Idle state, it only monitors fast paging channel. Because MS

only receives and demodulates little information, the power can be saved.

2.2 Call Flow

The following figure shows flow chart of calling/called party, involving air interface,

Abis, and A interface. Wherein, air interface and A interface are standardized, and

they are consistent with that in the relevant protocol standard, but Abis interface is

defined by the system manufacturer. The message sent on the PCH indicates an

interactive flow of MS and system during the call setup. If the network problems are

related to the call flow, analyze the problems based on the whole call flow.

Note: BSC handles the layer-2 acknowledgement for the originating message or

paging response message of access channel. To shorten the acknowledgement

time, the modifications are performed in VC03, and BTS directly perform layer-2

acknowledgement for the above two types of messages.

HLR

Origination MsgAbis-ACH Msg Transf er(ORM)

Abis-PCH Msg Transf er(BS Ack)Base Ack Order

Abis-BTS Setup

Abis-Connect

Abis-Connect Ack

Abis-BTS Setup Ack

Abis-is-2000 FCH Fwd(Null data)Null Traff ic Data

Abis-is-2000 FCH Rvs(Idle data)

Abis-PCH Msg Transf er(ECAM)ECAM

Traff ic Channel Preamble Abis-is-2000 FCH Rvs(Preamble)

Abis-is-2000 FCH Fwd(BS Ack)Base Ack OrderIdle TCH Data Abis-is-2000 FCH Rvs(Idle Data)MS Ack Order

Abis-is-2000 FCH Rvs(Ms Ack)

Abis-is-2000 FCH Fwd(Serv ice Connect)Serv ice Connect Msg

Serv ice Connect CompleteAbis-is-2000 FCH Rvs(Ser Conn Comp)

CM Serv ice Req

Assignment Complete

Assignment Req

ACH

PCH

TCH

PCH

TCH

TCH

TCH

TCH

TCH

TCH

Pagi ng R esponse Abis-ACH Msg Transfer(PRM)

Abis-PCH Msg Transfer(Base Ack)Base Ack Order

Abis-BTS Setup

Abis-Connect

Abis-Connect Ack

Abis-BTS Setup Ack

Abis-is-2000 FCH Fwd(Null data)Null Traffic Data


Abis-PCH Msg Transfer(ECAM)ECAM

Traffic Channel Preamble Abis-is-2000 FCH Rvs(Preambl e)

Abis-is-2000 FCH Fwd(Base Ack)Base Ack Order

Idle TCH Data Abis-is-2000 FCH Rvs(Idle D ata)

MS Ack Order Abis-is-2000 FCH Rvs(Ms Ack)

Abis-is-2000 FCH Fwd(Service C onnect)Service Connect Msg

Service Connect Com plete Abis-is-2000 FCH Rvs(Ser Conn C omp)

Pagi ng R esponse

Assignment Com plete

Assignment Req

Pagi ng R equestAbis-PCH Msg Transfer(GPM)GPM

Abis-IS-2000 FCH Fwd (AWIM)Alert with Info

Abis-IS-2000 FCH Rvs (MS Ack)MS Ack Order

Abis-IS-2000 FCH Rvs (Connect Order)Connect Order

Abis-IS-2000 FCH Fwd (BS Ack)BS Ack Or der Connect

CC(connection conf irm)

CC

Calling party BTS Calling party BSC MSCCalling party MS

Called party BSCCalled party BTSCalled party MS

LOCREQ (BILLID ,ORIID,DGTSDIALED)

(TRANSCAP, TAT)

Locreq (MIN ,ESN,MSC_ID ,PCSSN,ANNALIS )

(LOCALROUTINGINFO ,DMHDATA)

T)

HLR



Abis-BTS Setup

Abis-Connect

Abis-Connect Ack

Abis-BTS Setup Ack









CM Serv ice Req

Assignment Complete

Assignment Req

ACH

PCH

TCH

PCH

TCH

TCH

TCH

TCH

TCH

TCH



Abis-BTS Setup

Abis-Connect

Abis-Connect Ack

Abis-BTS Setup Ack










Pagi ng R esponse


Assignment Req

HLR



Abis-BTS Setup

Abis-Connect

Abis-Connect Ack

Abis-BTS Setup Ack









CM Serv ice Req

Assignment Complete

Assignment Req

ACH

PCH

TCH

PCH

TCH

TCH

TCH

TCH

TCH

TCH



Abis-BTS Setup

Abis-Connect

Abis-Connect Ack

Abis-BTS Setup Ack










Pagi ng R esponse


Assignment Req







CC









CC



LOCREQ (BILLID ,ORIID,DGTSDIALED)

(TRANSCAP, TAT)

Locreq (MIN ,ESN,MSC_ID ,PCSSN,ANNALIS )

(LOCALROUTINGINFO ,DMHDATA)

T)

Figure 2 Flow chart of calling/called party

3 Extended Bounary Paging Solution

3.1 Background

The following paging area bounarys are inevitable in the CDMA network:

Intra-BSC inter-LAC bounary

Intra-MSC inter-BSC bounary

Inter-MSC bounary.

Generally, the range of registration area is consistent with that of location area.

Wherein, registration area is used only for MS registration. That is, MS

originates a registration over registration area only in different registration

areas.

Location area is used only when system performs a paging to MS. It is paging

mode through which to send the range of paging message when MSC

originates a paging to MS. (CI is another paging mode.)

Because the conflict between the registration and paging in the above bounary

areas results in frequent/repeated registration or non-registration and lowers

successful paging ratio to affect network performance. MS sends the messages

on the reverse access channel during the registration, so frequent registrations

occupy the reverse access channel to affect normal call service. You can set

system parameter (such as Total-Zones or Zone-timer) related to registration in

the above bounarys to reduce the registration frequency and occupation of

reverse access channel. Meanwhile, you can adopt the special technology to

improve successful paging ratio of the above bounary.

The extended paging solutions are designed for the former two bounarys.

Inter-MSC bounary can adopt ISPAGE solution of later IS-41C recommendations.

No more descriptions are required here.

3.2 Implementation Principle and Solutions

3.2.1 Concepts

1. Extend: Enlarge and extend the paging range in case of the paging on

extended bounary.

2. True LAC: One of the cell attributes. It exists before extended bounary paging

solution is adopted. Some cells constitute the true LAC. Meanwhile, it is configured

in the LAC table of MSC, and is used for paging addressing.

3. Virtual LAC: It is used temporally during the application of extended bounary

paging solution. Some cells determine the scope defined in the BSC. It is not

configured in the LAC table of MSC.

4. Extended LAC: It includes many cells, and it can be either true one or virtual

one. Meanwhile, it is used to extend paging scope during the application of

extended bounary paging solution. If this extended LAC is virtual one, it is called

virtual LAC. Generally, the scope of virtual LAC is smaller than that of true LAC.

5. Adjacent LAC: Because extended bounary paging is extended between

adjacent LACs, extended LAC can be regarded adjacent LAC.

6. Center LAC: It is the original LAC when extended bounary paging is required,

and matched with extended LAC. Additionally, it is true LAC.

7. Extended cell: Extended LAC includes many cells, and the cell is extended

cell.

8. Bounary cell: The cell on a true LAC bounary.

3.2.2 Extended Bounary Paging Solution with a Cooperation Between MSC and BSC

This solution is implemented by MSC and BSC. An adjacent location area cell

table is added to MSC, as shown in table 1. Meanwhile, corresponding extended LAC

(adjacent LAC) is added to the location area cell table, and MSC configures extended

LAC (adjacent LAC). Wherein, extended LAC (adjacent LAC) can either belong to the

same BSC of the MSC or another BSC. Additionally, the cell scope of extended LAC

is also defined in BSC, that is, it belongs to an extended LAC by the adding of cell

attribute.

SN Field name Definition Default value Description

1 Paging LAC Index area Input is mandatory

Hex numeral.

The format and byte sequence are the same as LAI in location area cell table

2 Enable the whole The last paging is the whole

No If yes, the subsequent value is

MSC paging MSC paging (originate a paging to all the BSC of MSC)

invalid

3 Adjacent location area types

LAC or CI LAC Enumerated

4 Whether original LAC is included

Whether extended bounary paging scope includes original LAC

Yes If yes, adjacent location area cannot use CI.

5 Whether adjacent location area 1 is valid

Yes

6 Adjacent location area1

Input 4-digit hex numeral

Hex numeral 0xFFFF is an invalid value, and can be virtual LAC.(virtual LAC refers to that LAI instead of CI is configured in corresponding location area cell table).

The format and byte sequence are the same as LAI in location area cell table.

7–24 The same as 5 and 6.

6 LACs or 10 CIs adjacent location areas can be configured.

Default value must be provided. .

If adjacent location area i is “No”, valid default value is “No”.

Default value of adjacent location area: 0xFFFF

Table 1 Adjacent LAC cell

When MSC delivers a “Paging request”, query the Cell Information table of

adjacent location area to judge whether this LAC includes extended LAC (or adjacent

LAC).

If no, deliver a “Paging request” based on original LAC.

If yes, deliver a “Paging request” with corresponding extended LAC to BSC.

After receiving LAC information from MSC, BSC judges the LAC:

If this LAC is a true one, deliver a paging message based on true LAC range.

If this LAC is a virtual one, deliver a paging message based on cell range of BSC

defined virtually. The flow chart is shown in figure 3:

Figure 3 MSC delivers a “paging request”

[Note] The above functions are added to MSC side, and MSC can originate a

paging through multiple LACs/CIs. That is, MSC can carry multiple LACs or CIs for

BSC once, with the maximum of 6 LACs, and 10 CIs. In addition, MSC cannot carry

LAC and CI at the same time.

3.2.3 Intra-BSC Extended Bounary Paging Solution

The following two solutions do not require the cooperation of MSC, and are

implemented by intra-BSC automatically. To implement the following two solutions,

adjacent LAC correspondence and extended area table over idle handoff are added to

the BSC. Wherein, the former provides the correspondence between center LAC and

adjacent LAC. Obviously, center LAC and adjacent LAC belong to the same BSC, but

the latter provides the cell included in the extended LAC corresponding to a LAC (or

center LAC). Actually, this extended LAC is not put forth definitely.

[Note]

For the intra-BSC extended bounary paging solution, MSC should have originated a

paging to signaling A under the BSC, but originated a paging to signaling B and a

response is returned from signaling B. No. 20 software parameter of CCM in the

BSC controls the intra-signaling forwarding. Set 0x0 to disable the function by

default and set 0x1 to enable the function by executing command MOD SOFTPARA:

SRVMN=CCM, PRMNO=20, PRMV="0x01". Currently, actual test and verification

show that Huawei MSC can solve the above problems.

3.2.3.1 Extended Bounary Paging Solution True LAC-based

If a BSC includes several true LACs, configure adjacent LAC to be extended for

adjacent LAC correspondence during center LAC paging. Wherein, center LAC and

adjacent LAC are true LACs. MSC originates a paging based on center LAC, BSC

queries adjacent LAC correspondence to obtain the information about adjacent LAC to

be extended first, and then delivers paging messages to the LACs to implement

bounary paging function.

3.2.3.2 Extended Bounary Paging Solution Idle Handoff-based

To reduce paging traffic, and alleviate paging pressure, we obtain an extended

area with less scope over idle handoff based on the requirements of actual application

environment, and also implement extended bounary paging function. The procedures

are as follows:

1. Search the bounary cell configured under this LAC based on center LAC to

obtain bounary cell Celli;

2. Search adjacent area list set of corresponding idle handoff “Cellni+Cellmi”

based on Celli.

3. Delete Cellni of the center LAC from idle adjacent area list set “Cellni+Cellmi”.

4. Combine the repeated cells from remaining idle handoff list set “Cellmi” to

obtain final extended cell set “Cellmj”.

In this way, Cellmj constitutes the paging extended area. BSC obtains this paging

extended cell automatically, and you should configure bounary cell and adjacent

cell table of idle handoff relation in case of application.

3.3 Application Background

According to the principle and solved problem of above-mentioned extended

bounary paging solution, we determine whether to adopt the solution in the first two

bounary networks based on the paging of the two bounary areas. For details, see the

following suggestions.

3.3.1 Extended Bounary Paging Solution with a Cooperation Between MSC and BSC

If this solution is adopted, MSC should provide extended bounary paging function,

so this solution is applicable only when Huawei MSC is used. Because extended LAC

can be either true one or virtue one, concern the following:

If extended LAC is virtual one, this solution only is applicable to the

environment cooperating with Huawei BSC.

If extended LAC is true one, this solution can be applicable to the environment

cooperating with other manufacturer BSC. ,

This solution can solve intra-MSC inter-BSC bounary paging and intra-BSC

inter-LAC bounary paging. Take figure 4 for an example to illustrate the application

of solution.

Figure 4 Huawei networks with other manufacturers

Figure 4 shows the networking structure between Huawei MSC and Huawei BSC2

and other manufacturers BSC2. Wherein, LAC1, LAC2, LAC3, LAC5, LAC6 are true

LACs of two BSCs, but extended LAC7 is virtual LAC configured for BSC side. The

scopes of these LACs are defined by the real lien and broken line in figure 4, and

extended LAC7 is partial area of LAC5.

The bounary exists between Huawei BSC2 and other manufacturers BSC1, that is,

the bounary between LAC3 and LAC5. To solve the paging of this bounary, you

Huawei MSC

LAC1

LAC2 LAC3

Other manufacturers

BSC1 Huawei BSC2

LAC5 LAC6

Extended

LAC7

extend paging area after configuring extended LAC information related to LAC3 for

Huawei MSC and BSC side during the LAC3 paging.

If configure extended LAC of LAC3 as LAC5, paging area will be extended to

LAC5.

If configure extended LAC of LAC3 as extended LAC7 (virtual LAC), paging

area will be extended to extended LAC7 because the definition of extended

LAC7 is added to Huawei BSC.

Because the scope of extended LAC7 is less than that of LAC5, the paging traffic is

reduced to alleviate paging pressure of Huawei BSC.

You configure extended LAC of LAC5 as LAC3 or LAC6 for Huawei MSC to solve

the paging of bounary between Huawei BSC and other manufacturers BSC, and

Huawei intra-BSC respectively.

When you solve the paging of intra-BSC inter-LAC bounary, extended LAC can be

either true one or virtual one. Take figure 5 for an example to illustrate the

application of solution.

Figure 5 Cooperation implementation of intra-BSC inter-LAC

Figure 5 shows that LAC1, LAC2, and LAC3 are true LACs, and the scopes are

defined by the real line. But LAC4 is extended LAC, and it is virtual LAC. The scope

MSC

LAC1

Extended LAC4

LAC2 LAC3

BSC

MSC

LAC1 Extended

LAC4

LAC2 LAC3

BSC

(1) (2)

is defined by the broken line in figure 5 (1), and the dashed area is defined by broken

line in figure 5 (2).

According to extended bounary paging solution with cooperation between MSC

and BSC, you configure the information about different extended LACs of LAC3 for

MSC, and configure the cell included in this extended LAC for BSC.

If configure extended LAC as extended LAC4 in figure 5 (1), originate a paging

to extended LAC4 directly during LAC3 paging.

If configure extended LAC as extended LAC4 in figure 5 (2), originate a paging

to the area constituted by LAC3 and LAC4 during LAC3 paging.

In this way, you expand paging scope to enhance successful paging ratio of LAC3.

[Note] The above figure is only for description, and irrelevant with actual application

solution.

3.3.2 Intra-BSC Extended Bounary Paging Solution

Intra-BSC extended bounary paging solution is applicable when Huawei BSC

exists in the network only. Under other circumstances, you should adopt the above

solutions, and select the sub-solution flexibly based on actual network situation:

(1) Extended bounary paging solution over true LAC

(2) Extended bounary paging solution over idle handoff

If there are many LACs delivered by BSC, and each LAC does not include many

cells, adopt solution (1). In this way, over-large paging traffic does not occur.

If there are less LACs delivered by BSC (such as 2 LACs), but each LAC includes

many cells, adopt solution (2). In this way, you obtain extended cell set with small

scope and implement extended bounary paging function to solve the paging

intra-BSC inter-LAC bounarys.

3.4 Data Configuration

3.4.1 MSC Data Configuration

1. Extended bounary paging solution switch

Controlled by No. 87 software parameter

Bit0: Whether to enable paging optimization function.

0: No

1: Yes (default)

For MSC, enable the extended bounary paging solution by default. For details,

see M800 MSCV610R002 Software Parameter Usage Guide (new).doc.

Maintenance console command: MOD/LST SFP

2. Adjacent LAC Table

The structure is shown in table 1, and you should add the information about

adjacent LAC.

Maintenance console command: ADD/MOD/RMV/LST NEIGHBORLAC

Note:

(1) When extended bounary paging solution is adopted, LAC of BSC

delivered by MSC may include original LAC, or may not. But it is

included by default.

(2) Enable the extended bounary paging solution duirng the last

paging. For example, if there are twice for resending, the system

orignates a paging three times. The extednded bounary paging

solution is enabled duirng the third paging. If resendign does not exist

(that is only a paging), disable the extended bounary paging solution.

No. 88 software parameter controls the resending times.

(3) The extended bounary paging solution is valid only for

PagingRequest of voice/data service, so does for BSC extended

bounary paging solution.

3. LAC cell table

If extended LAC is true one, you should add the information about LAC and the

call included in LAC to LAC cell table to used in case of LAC and CI paging

modes.

If extended LAC is virtual one, you should only add virtual LAC to the LAC cell

table. In addition, between extended LAC and original LAC, and extended

LACs should not be overlapped. In this case, we avoid potential problems

because of over-large paging to the cell.

Maintenance console command: ADD/MOD/RMV/LST LAIGCI

3.4.2 BSC Data Configuration

1. Extended Mode

BSC extended mode includes the following:

0) Non-extension

1) Extension based on true LAC

2) Extension over idle handoff

3) MSC extension

(Default value: 0, that is, extended mode is the non-extension.)

So MSC enables extended bounary paging solution by default, but BSC is

performed based on the MSC mode when it is not extended by default. But BSC is not

extended, BSC judges the extended LAC sent from MSC. If this LAC is virtual one,

BSC will not deliver a paging to this virtual LAC. If this LAC is true one, BSC delivers

a paging this true LAC. Actually, MSC sends multiple true LACs.

If BSC delivers a paging to a virtual LAC, you set 3) MSC extension to the BSC

extended mode. 1) and 2) modes are used when intra-BSC implements extended

bounary paging solution automatically.

Maintenance console command: MOD/LST EBPGPARA

2. Extended Strategy

This parameter is valid only for intra-BSC extended bounary paging solution, that

is, this parameter is valid only for mode 1) and 2).1) Extension starts in case of the

paging for the first time. 2) Extension starts in case of the paging for the second

time 3) Extension starts in case of paging for the third time. Generally, we select 3).

Maintenance console command: MOD/LST EBPGPARA. For example: MOD

EBPGPARA: EXTBNDPAGEMODE=REALPAGE, STRATTIME=3

Extended mode and strategy are configured in the paging parameter table.

3. Adjacent LAC Correspondence

This table is used only intra-BSC extended bounary paging solution over true LAC,

indicating the extended relation between true LACs. One center LAC can have 6

adjacent LACs instead of repeated adjacent LACs. But one center LAC should

not have more than 2 adjacent LACs if paging traffic is considered.

Maintenance console command: ADD/MOD/RMV/LST NBRLAC.

You delete some adjacent LACs by executing command MOD NBRLAC, and only

fill “-” in the corresponding place where the parameter is located.

4. Adjacent cell table of idle handoff

It is used only when the extended mode over idle handoff is selected. Pay attention

to the change in case of the change of network structure.

5. Cell attribute

Extended LAC (virtual LAC) in the MSC extended mode and bounary cell in the

extended mode over idle handoff are expressed in the cell attributed. You set the

cell to be an extended LAC by executing a command or define the cell as a

bounary cell.

[Note]: The bounary cell may change following such network structure as new cell.

You obtain LAC corresponding cell list in the module (including the cell in the

extended LAC), extended cell table over idle handoff, and LAC, module and

signaling correspondence of the BSC, as shown in figure 6.

Maintenance console command: ADD/MOD/RMV/LST CELL

3.5 Precautions

1. Determine the extended bounary paging solution based on actual networking

environment, and configure MSC and BSC parameters correspondingly during the

paging solution with cooperation between MSC and BSC.

2. Consider the bad effect because of expansion of paging scope during the selection

of extended LAC, that is, you should pay more attention when defining extended

LAC because paging pressure and traffic increase.

3. Concern the adding and modification of larger data configuration during the

application of extended bounary paging solution.

4. Change extended LAC and extended cell scope over idle handoff of extended

bounary paging solution correspondingly in case of network expansion.

5. Concern CPU utilization of BSC SPU, BTS paging traffic measurement, and

successful MSC paging ratio during the application of extended bounary paging

solution.

4 Optimization of BSC and BTS Paging Algorithm

4.1 Purpose

The processing for paging channel message is indispensable before call flow

goes on. So the optimization for processing algorithm can perfect the whole call flow

to ensure relevant performance indices. For example, BTS instead of BSC handles

L2 acknowledgement of access channel message to shorten the acknowledgment

time.

In respect of the whole call flow, we optimize paging algorithm aims to:

Enhance reliability of paging message acceptance and utilization efficiency of

paging channel.

Ensure validity of paging message and superiority of high-level service.

Avoid affecting the normal processing of voice service because of too many

SMs to ensure the strength of the system in case of the exceptions.

4.2 Implementation Solution

4.2.1 Cooperation Mechanism between BSC and BTS

In the earlier VR03C03, message resending mechanism at LAC layer

implemented by BSC includes the following four types of messages:

Acknowledged message on the common channel

Non-acknowledged message on the common channel.

Acknowledged message on the dedicated channel.

Non-acknowledged message on the dedicated channel.

Acknowledged/non-acknowledged mode refers to that whether the L2

acknowledgement is required. In VR03C03, we modify message resending

mechanism at LAC layer, as shown below:

The messages include F-CSCH and F-DSCH.

Adjust the settings for minimum detection interval of message sending at LAC

layer, message sending times and interval at LAC layer, and acknowledged

mode or not dynamically.

Minimum detection interval of message sending at LAC layer changes from

50ms only to 10ms/20ms/30ms/40ms/50ms (default value: 20ms).

Message sending interval changes from integral times of 50ms to integral

times of 10ms/20ms/30ms/40ms/50ms (default value: Integral times of

20ms).

Messages sent on paging channel belong to F-CSCH message. For details,

see the parameter configuration in section 4.4.

No more descriptions about the messages sent on F-DSCH are required

here.

To optimize paging algorithm, ensure the effect of message resending, perform

the following:

Avoid resending BSC but send BTS in the same slot.

Discriminate message levels, perfect BTS scheduling mechanism, and

ensure stable system based on the analysis of network SM problem to add

such fields as message level, slot, message living time and resending times

to BSC and BTS interface.

BSC sends the paging message levels except those of general messages,

their living time, and resending times to BTS through Abis interface.

BTS performs relevant processing based on BTS scheduling mechanism.

Currently, message levels include the messages related to the call and unrelated

to the call. The priority of former is higher than that of latter.

The former includes GPM of voice service, GPM of circuit and packet data

service, ECAM/CAM, BS Ack Order, and other Order messages (such as

release order) and unique challenge message (such as authentication).

The latter includes DBM, GPM used to locate SM, feature notification

message, and broadcast message.

Life cycle is the living time of resending paging message in the BTS message

queue. If the living time exceeds life cycle, delete the messages from BTS

message queue. Currently, the life cycle takes 80ms as a unit.

Resending times refers to the times that BTS sends paging message repeatedly.

When resending times is set to 0, BTS does not resend the paging message.

When resending times N is more than 0, BTS sends the paging message for n+1

times.

For the acknowledged or non-acknowledged messages on PCH, see table 2.

PCH Message Acknowledged or not

Channel Assignment Message Non-acknowledged

Extended Channel Assignment Message

Non-acknowledged

General Page Message Do not belong to the two types of messages

Data Burst Message Acknowledged

Authentication Challenge Message Acknowledged

Feature Notification Message Acknowledged

Service Redirection Message Non-acknowledged

Bs Ack Order Message (ARQ sub-layer of LAC)

Non-acknowledged

Order Message Non-acknowledged

If BTS resends Bs Ack Order Message at LAC ARQ sub-layer in VC03, disable

BSC sending mechanism and it is controlled through software parameter. For details,

see the parameter configuration in section 4.4.

BTS determines whether to carry the life cycle and resending times of the message,

and the resending times and life cycle can be set in the BTS.

4.2.2 BTS Paging Scheduling Mechanism

According to the above-mentioned cooperation mechanism of BSC and BTS,

BSC transfers priority level, life cycle, and reseeding times, but BTS performs

relevant scheduling and processing. According to the priority level of paging message

and slotted or not, paging messages based on the scheduling sequence include:

General message

Slotted message related to the call, including GPM of voice and data service,

and slotted unique challenge message

Unslotted message related to the call, including CAM/ECAM, BS ACK Order,

Release Order

Slotted message unrelated to the call, including GPM and DBM to locate SM.

Unslotted message unrelated to the call

Broadcast message

The above messages are stored in corresponding queues based on the sequence

sent by BSC. For slotted messages, the queue varies with the slot. BTS schedules and

sends the paging messages on the paging slot based on scheduling sequence. If there

are no messages to send in the queue with high scheduling priority, search the

message queue with lower priority, and then send the messages.

If the messages are resent, you should transfer the message to resending queue

after it is sent once, and schedule the message when queue scheduling is completed

at the same level.

For the slotted message, the shortest scheduling period in the BTS is a slot. If

the special slot is not sent during the first slot cycle, send the corresponding

slot during the next slot cycle.

For the unslotted message, the shortest scheduling period in the BTS is a slot,

that is, the unslotted message is sent during a slot. If the slot is not sent during

the slot cycle, the shortest scheduling period is the next slot.

In addition, the living time in the queue is subject to life cycle.

Life cycle: The time when the message is sent to the queue to that the message is

deleted from the queue after the life cycle duration.

Because discriminating the priority of message related/unrelated to the call, we

ensure that:

The system can handle voice and data service normally even in the case of

SM congestion.

Normal conversation.

The system is not affected by SM to enhance strength of the system.

Configure rational life cycle and resending times to ensure the validity and

reliability of message acceptance.

4.2.3 GPM Combination Function

The above measurers are to improve the smoothness of the whole flow. But GPM

combination is to enhance the utilization efficiency of paging channel. GPM

combination is allowed impliedly in the protocol in case of GPM structure description.

GPM structure is as follows:

Field Length (bits)

MSG_TYPE („00010001‟) 8

CONFIG_MSG_SEQ 6

ACC_MSG_SEQ 6

CLASS_0_DONE 1

CLASS_1_DONE 1

TMSI_DONE 1

ORDERED_TMSIS 1

BROADCAST_DONE 1

RESERVED 4

ADD_LENGTH 3

ADD_PFIELD

Zero or more occurrences of the following page record:

PAGE_CLASS 2

PAGE_SUBCLASS 2

Page type-specific fields 38-184

RESERVED 0 - 7 (as needed)

0 or several “Page Records” are included in the structure. But “Page type-specific

fields” include the information about MS and service option. “Page records” with

different formats have different types. For example, the format of “Page type-specific

fields” is as follows:

Field Length (bits)

MSG_SEQ 3

IMSI_S 34

SPECIAL_SERVICE 1

SERVICE_OPTION 0 or 16

GPM combination means that:

Combine the MS information with the information about relevant service

option, and send them.

Original several GPMs with respective special field are sent in a GPM through

shared common field.

Enhance the utilization of paging channel.

Under the circumstance of “Page record” in a format, the utilization enhancement

result through analysis is shown below:

If N*GPM are combined, the decrease ratios of occupied bits before and after

GPM combination are as follows:

When n is set to 2, the decrease ratio is 32/128=25%.

When n is set to 3, the decrease ratio is 47/128=36.7%.

Whatever GPMs are combined, the maximum decrease ratio for paging channel

occupation is 70/128=54.7%. Generally, the GPM occupation for paging channel

is 20–30%, and the maximum decrease ratio is 11-16% after GPM combination

strategy is adopted.

When n is set to 2, the decrease ratio is 5–7.5%.

When n is set to 3, the decrease ratio is 7–11%.

This function has been implemented in VC03, and two control parameters are

available: Number of combined GPM and number of GPM search.

The former ranges from 0 to 15, that is, at most 3 GPMs are combined. If o

times are set, disable GPM combination function.

The latter is the specified queue query size in case of GPM query. Too large

queue will affect processing performance of channel board. It is set to 20 by

default.

You can configure the two parameters through .ini file (see section 4.4.3), and

optimize them after the actual network application.

4.3 Paging Measurement Index and Analysis

Paging measurement indices are added in VC03 based on actual network

application. With the implementation of following BTS traffic measurement, some

indices included in BSC traffic measurement are transferred to BTS traffic

measurement. The specific indices are as follows:

1. Occupation of sent messages related to the calls [%], including the shared

occupation of slotted message and unslotted message related to the calls.

2. Occupation of sent messages related to SM [%], including the shared occupation

of slotted message and unslotted message unrelated to the calls.

3. Occupation of all the sent messages [%]. The three indices are designed for the

occupation of paging channel.

4. PCH occupation [%] is the sum of the above three indices. Actually, there are also

SCI bit occupation and null GPM occupation. SCI bit occupation is constant, so it is

not required to consider it. But null GPM is sent until the system has no any other

messages to send, the occupation of paging channel will be up to100%. To reflect

actual message occupation in the network, you should not add null GPM

occupation. If occupation of PCH busy hour exceeds a threshold (such as 80%),

paging channel is occupied much. So the expansion for paging channel is

required.

5. Occupation of lost message related to the calls [%]=Total bytes of lost messages

related to the calls/total bytes of received messages (resent messages included)

6. Occupation of lost messages related to SM [%] =Total bytes of lost messages

unrelated to the calls (resent messages included).

7. GPM combination efficiency: The GPM combination efficiency of voice and SM is

measured respectively.

Definition: Set a measurement cycle T to 300s. If you send GPM with combination

strategy: Combine M*GPM with K times, and N*GPM are not combined, the

efficiency enhancement ratio is:

[(N+(k+1)*M)-(M+N)]/(N+(k+1)*M)=K*M/(N+(K+1)*M)

Obviously, when N is set to 0, the efficiency enhancement ratio is the maximum

(that is, K/(K+1)).

When K is se to 1, the ratio is 50%.

When K is set to 2, the ratio is 67%.

The provision of calculation formula (numerator/denominator) instead of specific

percentage during the actual implementation facilitates knowing the number of

sent GPM during a period.

The following indices are used to locate the relevant personnel of internal BTS

scheduling mechanism and detect paging scheduling mechanism. You should

not concern them in general. The indices are to grasp and understand the

information about message sent, and analyze whether the settings of queue size

and living time are appropriate. The sum of following (8), (9), (10), (11), and (13)

is the total number of slotted messages related to the call in the queue, but that of

(8), (9), (10), (11), (12), and (13) is the total number of slotted messages related

to the call before they are sent in the queue. So do for the slotted messages

unrelated to the call.

8. The number of messages sent without delay (slotted messages related to the call)

9. The number of messages sent with a delay of one slot cycle (slotted messages

related to the call)

10. The number of messages sent with a delay of two slot cycles (slotted messages

related to the call)

11. The number of messages sent with a delay of three or more slot cycles (slotted

messages related to the call)

12. The number of discarded messaged because of queue saturation (slotted


13. The number of discarded messages because living time exceeds (slotted


14. The number of messages in the queue (unslotted messages related to the call)

15. The number of messages deleted before the queue (unslotted messages related

to the call)

16. The number of discarded messages because living time exceeds (unslotted


17. The number of messages sent without delay (slotted messages unrelated to the

call)


unrelated to the call)


unrelated to the call)

20. The number of messages sent with a delay of three or more slot cycles (slotted

messages unrelated to the call)

21. The number of discarded messaged because of queue saturation (slotted


22. The number of discarded messages because living time exceeds (slotted


23. The number of messages in the queue (unslotted messages unrelated to the call)

24. The number of discarded messaged because of queue saturation (unslotted


25. The number of discarded messages because living time exceeds (unslotted


4.4 Parameter Configurations

4.4.1 Default Value of F-CSCH Message Resending Parameter

LAC layer resending mechanism includes two types of messages: F-CSCH

message and F-DSCH message. The latter does not belong to the content of paging

optimization. So no more descriptions are required here. For details, see Guide to

Resending Parameter at LAC Layer Provided by BSC. For the parameter setting of the

former, see table 3.

Table 3 F-CSCH Message Default Value

F-CSCH Message ID Acknowledged

mode

Sending

times at

LAC

layer

Sending interval

at LAC layer (ms)

Authentication

Challenge

Message

(AUCRM)

00001010 Acknowledged,

DB cannot be

modified

1, and

DB

cannot

be

modified

5000 (Because

the message is

not sent, the

interval is the

time that LAC

layer waits for MS

acknowledgment)

Bs Ack Order

Message(BSACKM)

11111110 Non-acknowledged,

and DB cannot be

modified

3 300

Channel

Assignment

Message(CAM)


and DB cannot be

modified

10 300

Data Burst

Message(DBM)

00001001 Acknowledged, and

DB cannot be

modified

1, and

DB

cannot

5000 (Because

the message is

not sent, the

be

modified

interval is the

time that LAC

layer waits for MS

acknowledgment)

Extended Channel

Assignment

Message(ECAM)


and DB cannot be

modified

10 300

Feature Notification

Message(FNM)

00001100 Acknowledged, and

DB cannot be

modified

1, and

DB

cannot

be

modified

5000 (Because

the message is

not sent, the

interval is the

time that LAC

layer waits for MS

acknowledgment)

Order

Message(ORDM)

00000111 Non-acknowledged 3 300

Service Redirection

Message(SRDM)

00010000 Non-acknowledged 3 300

The default values in the table are only applicable when paging living time is not

activated and BTS does not resend paging channel message. Once the function is

enabled, you should adjust the default values. For details, see table 5 in section

4.4.2.

DBM, FNM, and AUCRM are sent in the mode of slotted message. For the

setting of default value, consider the minimum paging slot cycle.

Set “Release Order” at LAC layer to Non-acknowledged, and it cannot be

changed.

Set “Bs Ack Order Messager” at LAC ARQ sub-layer to Non-acknowledged,

and it cannot be changed.

Resending times at LAC layer: 0–20.

Resending interval at LAC layer: 0–8000ms.

The maximum error of message detection mechanism is “minimum detection

interval of message sending at LAC layer". If [Sending interval]/[Minimum

detection interval of message sending at LAC layer] is not set to 0, the error may

be “minimum detection of message sending at LAC layer” because of the round

error. So you should set “Sending interval” to integral times of “Minimum detection

interval of message sending at LAC layer”. For example, if “Minimum detection

interval of message sending at LAC layer” is set to 20ms, set “Sending interval” to

20×n. This is a reference default value. You should adjust the parameters during

the actual network test to obtain the best experience value, and then submit it to

relevant Dept. for database modification.

Minimum detection interval of message sending at LAC layer: When the F-CSCH

is available, the parameter ranges from 50ms to 100ms but it is defaulted to be 100ms.

When the F-DSCH is available, the parameter ranges from 10ms to 50ms, that is, the

minimum detection interval of message sending at the LAC layer changes from 50ms

to any one of 10ms, 20ms, 30ms, 40ms or 50ms but it is defaulted to be 20ms. In this

case, the interval of message sending changes from the integral times of 50ms to

that of 10ms, 20ms, 30ms, 40ms or 50ms but it is defaulted to be that of 20ms.

Modification/query command: MOD/LST LACCTRL

Minimum detection interval of message sending at LAC layer

Modification command: MOD LACMSGINTERVAL

4.4.2 Resending Times and Living Time of Paging Channel Message

You can set resending times and living time of paging channel message based on

different messages. Wherein, maximum resending times: 15, and Unit of living time:

80ms. For the paging channel message and corresponding ID, see table 4.

Table 4

PCH ID

Channel Assignment Message 0

Extended Channel Assignment Message

1

General Page Message 2

Data Burst Message 3

Authentication Challenge Message 4

Feature Notification Message 5

Service Redirection Message 6

Order Message 7

Other message 8

Wherein, “other message” is designed for its perfectness, and it is not used

currently because of the purpose at later stage. When the living time of paging

message is activated, and BTS supports the resending of paging channel message,

set the parameter of paging channel by default. For details, see table 5.

Table 5 Parameter setting of paging channel message

F-CSCH Message Sendi

ng times

at LAC

layer

Sendin

g interval at

LAC layer

(unit: ms)

Living

time

(unit:

80ms)

Resending

time9s

Authentication

Challenge Message

(AUCRM)

1 5000 24 0

Channel Assignment

Message (CAM)

3 1000 12 3

Data Burst Message

(DBM)

1 5000 24 0

Extended Channel

Assignment Message

(ECAM)

3 1000 12 3

Feature Notification

Message (FNM)

1 5000 24 0

General Page

Message (GPM)

None None 64 0

Order

Message(ORDM)

1 0 24 2

Service Redirection

Message (SRDM)

1 0 24 2

Modification command: MOD/LST FCSCHMSGPARA

Precautions for parameter configuration:

1. The table 5 shows the following:

“None” indicates that there are no relevant parameter setting

“0” in the “Sending interval at LAC layer” column indicates that LAC resending

is not required for the message.

“1” in the “Sending times at LAC layer” and “5000” in the “Sending interval at

LAC layer” indicate that it is not required to resend this message at LAC layer.

5000(ms) indicates the time of LAC layer waits for MS answer, which is the

same as that in table 3.

“0” in the “BTS sending times” indicates that the message is resent at upper

layer instead of LAC layer of BSC and BTS.

2. The parameter setting is applicable when paging message living time is activated

and BTS paging channel message is resent. The paging message living time

function can be disabled only when “enable PCH living time” is set to 0 at the BTS

(it is caused by the matching of ABIS interface). But the paging message

resending function can be disabled not only when the resending times are set to 0

at the BTS but also “enable PCH retransmission” is set to 0 at the BTS.

3. Whether BTS supports L2 acknowledgment for access channel message,

including the following:

a. If all the BSs of BSC do not support L2 acknowledgement for reverse access

channel message, BSC sends L2 software parameter switch, and enables the switch

(that is, No. 39 software parameter of CCM. Default value: 0x00000001). At that time,

send the “Bs ACK Order Message” based on the parameter set in table 3.

b. If all the BSs of BSC support L2 acknowledgement for reverse access channel

message, disable the software parameter (that is, No. 39 software parameter of CCM.

Default value: 0x00000000). At that time, sending times and interval at LAC layer of

“Bs ACK Order Message” is invalid. For BTS, enable L2 acknowledgement switch of

access channel. For the setting of resending times and living time, see section 4.4.3.

c. If some BSs of BSC support L2 acknowledgment for reverse access channel

message, but some do not support, enable No. 39 software parameter of CCM.

To facilitate understanding living time and resending times of paging channel

message, see the following example:

If you set the sending times of ECAM at LAC layer of BSC to 3, and resenting

interval at LAC layer to1000ms, it indicates that BSC resends ECAM 3 times

at most, and resending interval is 1000ms.

If BSC receives Preamble of reserve service channel, resending the message

stops at LAC layer. When you set the living time and resending times to 12

and 3 respectively, it indicates that BTS resends the message 4 times at most

(add once for BTS), and the living time at BTS is 12×80ms=960ms. Once the

living time expires or resending completes, BTS deletes all the information

about the message.

After sending ECAM at LAC layer twice, BSC receives Preamble of reverse

service channel. In this way, BSC sends ECAM twice, but BTS sends two

cycles of ECAM (send ECAM four times at most for each cycle, and the living

time of BTS in each cycle is 960ms).

The setting of resending times should consider the effect of paging channel

occupation, but that of living time should consider the cooperation with the timers

involved in the whole call flow.

For the GPM, MSC controls resending times and interval. For details, see figure 6.

GPM living time should cooperate with paging resending interval timer T3113 of MSC,

but whose living time should be less than T3113. The living time of CAM/ECAM should

consider the cooperation with CCM_T_WT_TCH_PREAMBLE of TCH Preamble, and

should be less than this timer.

Figure 6 Simple call flow diagram

4.4.3 L2 Acknowledgement Parameters for Access Channel Message

1. L2 Acknowledgement Switch of Access Channel Message from BSC

Controlled by No. CCM39 software parameter.

Modification command: MOD SOFTPARA.

1: Enable, and 0: Disable.

The control requires the cooperation with BTS parameter.

2. L2 Acknowledgement Switch of Access Channel Message from BTS

Resending times: 2 (default value)

Living time: 16×80ms (that is, 1.28s).

You modify the above two parameters by modifying .ini file of BTS. For the file format,

see Annex 1. The specific parameters are as follows:

EnableL2AckOrderCtrl = 1; (L2 acknowledgement control: 0: Disable and 1: Enable)

L2AckOrderLivingTime = 16; (L2 acknowledgment living time: 1–255 (unit: 80ms))

L2AckOrderResendNum = 2; (L2 acknowledgement resend times: 0–15)

EnablePCHLivingTime = 1; (Enable PCH living time: 0: Disable and 1: Enable)

EnablePCHResend = 1; (Enable PCH resend: 0: Disable and 1: Enable)

GPMCombineNum = 2; (GPM combination number: 0–15)

GPMSearchNum = 20; (GPM search number: 1–100)

4.4.4 Parameter and Function Verification

Verify BSC and BTS paging optimization algorithms through the following methods:

1. Query the modified living time and resending times by executing command LST,

and view them through Abis message tool provided by BTS. For details, see Annex

2. Because the test tool is for intra-BTS use only, and intra-BTS maintains its

version, BTS relevant engineer provides on-site operation or guide for personnel

using the function.

2. View directly the GPM combination function through air interface signaling. The

case is as follows:

RecNo : 2390 : 2003-8-21 08:43:00.201 : PAGING : General Paging Message (GPM)

Record_Header, ,,

RECORD_LENGTH, 43, bytes,

LOG_CODE, 0x1007,,

MESSAGE_TIMESTAMP, 08:43:00.201,,

EXPECTED_MESSAGE_LENGTH, 31, bytes,

Message, ,,

Paging Channel Message.0, ,,

MSG_LENGTH, 31, bytes,

RESOLVE_PD, ,,

PD.0, ,,

MSG_ID, 17,,

SDU_AND_PDU_PADDING_LENGTH, 202, bits,

General Paging Message, ,,

MOB_SPECIFIC_MSG, 1,,

CONFIG_MSG_SEQ, 8,,

ACC_MSG_SEQ, 37,,

CLASS_0_DONE, 1,,

CLASS_1_DONE, 1,,

TMSI_DONE.0, 0,,

ORDERED_TMSIS.0, 0,,

BROADCAST_DONE, 1,,

RESERVED, 0,,

ADD_LENGTH, 0,,

ADD_PFIELD, 0,,

[3], ,,

PAGE_CLASS.0, Class 0 : Mobile Station Addressed,,

PAGE_SUBCLASS.0, 0,,

MSG_SEQ.0, 3,,

IMSI_S.0, ,,

IMSI_S, (009) 830-1618――――――――(1),,

IMSI_S2.0, (009),,

IMSI_S1.0, 830-1618,,

NON_IS2000_PAGE_CLASS_FIELDS.0, ,,

ADDR_MATCH.0, 0,,

SDU_INCLUDED.0, 1,,

SERVICE_OPTION.0, ,,

INCORRECT_SO, Enhanced Variable Rate Voice Service (8 kbps),,

Proprietary_Indicator.0, 0,,

Service_Option_Revision.0, 0,,

Base_Service_Option_Number.0, 3,,



MSG_SEQ.0, 6,,

IMSI_S.0, ,,

IMSI_S, (078) 839-8698―――――――― (2),

IMSI_S2.0, (078),,

IMSI_S1.0, 839-8698,,


ADDR_MATCH.0, 0,,

SDU_INCLUDED.0, 1,,








MSG_SEQ.0, 5,,

IMSI_S.0, ,,

IMSI_S, (078) 842-0782――――――――③,,

IMSI_S2.0, (078),,

IMSI_S1.0, 842-0782,,


ADDR_MATCH.0, 0,,

SDU_INCLUDED.0, 1,,






MSG_END_PADDING, ,,

IS2000_L2_PDU_PADDING, ,,

PDU_PADDING.0, 0,,

CRC, 631086185,,

The above GPM includes three IMSI information (such as (1) (2), and ③).

3. View and analyze BTS paging scheduling function through paging traffic

measurement.

5 Application Cases

1. The inappropriate settings for resending times and interval timer of DCH

Unacknowledged Mode message result in the MS authentication failure, and MS

cannot originate a call normally.

[Descriptions]

Set the resending times of DCH Unacknowledged Mode message at LAC

layer in an office to 5 and resending interval timer to 100ms. That is, the interval

from the first message to the last resending message is 5×100=500ms.

The authentication procedures are as follows:

1. After receiving an “Assignment Complete”, the network side originates an

authentication. At that time, a RAND is generated and the network side delivers this

RANDO to MS through an “Authentication Indication Request”.

2. After receiving MSC authentication indication, MS takes RAND delivered from

MSC, A-KEY in the SIM (actually, SSD instead of A-KEY), MIN (the last 10 digits of

IMSI), and ESN as the authentication elements to generate the authentication result

through authentication algorithm, and sends the result AUTHR1 to MSC.

3. MSC forwards the authentication elements and result from MS to HLR/AC.

4. HLR/AC takes A-KEY value of this subscriber saved in the MIN, ESN, RAND

and AC, and generates a new result AUTHR2 through the same authentication

algorithm. If AUTHR1 is consistent with AUTHR2, the authentication succeeds, and

the subscriber is a valid one. Otherwise, the subscriber is an invalid one, and will be

rejected.

The authentication includes the calling authentication and called authentication

on the traffic channel, and Unique Challenge Authentication originated by HLR when

MS is in IDLE state. Because the protocol is imperfect, and current network closes the

authentication originated by location registration, no more descriptions are detailed

here. The former authentication message (SSD Update Message) is sent in an

Unacknowledged Mode on the traffic channel, and the latter one (Unique Challenge

Message) is sent in an Acknowledged Mode on the paging channel (current network

does not support SSD Update Message on the paging channel). Meanwhile, the

detection cycle of authentication message copy sent in the Acknowledged Mode on

the DCH is 320ms.

500ms is greater than the detection time of message copy based on the

above-mentioned setting (320ms), so MS thinks a new message is sent by

mistake to send new authentication data. In this case, the two authentication

results of network side are inconsistent, and the authentication will fail.

Therefore, the resending interval of authentication message sent in an

Unacknowledged Mode on the DCH should not be greater than corresponding copy

detection cycle. The detection cycle of message copy sent in an Unacknowledged

Mode on the common channel is 2.2 second stipulated in the protocol, so the lifecycle

of authentication message sent in an Unacknowledged Mode on the common channel

should not be greater than copy detection time. Because ECAM and CAM are on traffic

channel instead of paging channel, the exceptional problems do not exist in case of

copy detection.

07-CDMA2000 Paging Optimization Guide

Documents

Transcript of 07-CDMA2000 Paging Optimization Guide