Precise Paging Feature Guide

ZGO-02-01-002 Precise

Paging

Feature Guide

Formatted: Space Before: 1 line

ZGO-02-01-002 Precise Paging

ZTE Confidential Proprietary 1


Version Date Author Reviewer Notes

V1.0 2012/06/18 Luo Zhiwen

GU Commercial

System Supporting

Dept.

Not open to the third party

© 20142012 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used

without the prior written permission of ZTE.

Due to update and improvement of ZTE products and technologies, information in this document is subjected to

change without notice.


2 ZTE Confidential Proprietary

TABLE OF CONTENTS

1 Feature Attribute ....................................................................................................... 4

2 Overview ..................................................................................................................... 4

2.1 Feature Introduction ..................................................................................................... 4

2.2 Correlation with Other Features.................................................................................. 6

3 Technical Description............................................................................................... 7

3.1 Determination of VPC and HPC ................................................................................. 7

3.2 Subscriber Data Management .................................................................................... 7

3.3 Coordination with Core Network ................................................................................. 8

3.4 Support for Paging Hole Analysis ............................................................................... 9

3.5 Repaging .................................................................................................................... 10

3.6 Flow Control ............................................................................................................... 10

4 Parameters and Configurations ........................................................................... 11

4.1 Parameter List ............................................................................................................ 11

4.2 Parameter Configuration ........................................................................................... 11

5 Related Counters and Alarms ............................................................................... 15

5.1 Related Counters ....................................................................................................... 15

5.2 Related Alarms ........................................................................................................... 16

6 Engineering Guide .................................................................................................. 17

6.1 Application Scenario .................................................................................................. 17

6.2 Configuration Description .......................................................................................... 17

6.3 Network Impact .......................................................................................................... 18

7 Abbreviation ............................................................................................................. 19

8 Reference Document .............................................................................................. 19



FIGURES

Figure 4-1 BSC Precise Paging Configuration Interface ........................................................ 12

Figure 4-2 Cell Precise Paging Configuration Interface .......................................................... 13

Figure 4-3 Visit Paging Cell configuration Interface ................................................................ 14

TABLES

Table 4-1 Parameter List ........................................................................................................... 11

Table 5-1 Counters List ............................................................................................................. 15



1 Feature Attribute

BSC Version: [ZXUR 9000 GSM (V6.50.100)]

BTS Version: [For SDRV4.11.10 and later versions]

Property: [Optional]

Related Network Element:

NE Name Related or Not Special Requirements

MS √

BTS √

BSC √

iTC -

MSC √

MGW -

SGSN √

GGSN -

HLR -

Dependent Function: [None]

Exclusive Function: [None]

Note: [None]

2 Overview

2.1 Feature Introduction

In the case of a large number of subscribers and high PS traffic load in a location area,

there will be a great number of paging messages and immediately assigned messages

on the CCCH channel and consequently congestion easily arises. One solution to this

situation is to configure more CCCH channels, but this solution will reduce the available

Formatted: Widow/Orphan control

Formatted: Left, Widow/Orphan control











service channels. Therefore, the precise paging method is considered. First paging is

performed in some cells where it is more probable to find subscribers and then the

paging area is extended to the area required by the core network. As the first small-area

paging presents a relatively high probability of finding subscribers, the number of paging

messages is decreased and this in turn can save CCCH channels and increase the

configuration service channels. The precise paging feature is described as follows:

1. The network first sends a paging message to a cell and the neighbor cells within its

location area or routing area according to the location record saved in the BSC. If

the mobile station does not respond to that message within a given period of time,

then the BSC will also send the paging message to other cells within the LA/RA.

2. If the precise paging feature is not enabled for a cell and the known MS is located

within that cell, then normal paging will be used. The precise paging feature should

be able to be enabled as follows at the cell level:

i. Only the CS uses precise paging;

ii. Only the PS uses precise paging;

iii. Both the CS and PS use precise paging.

3. In case of precise paging, paging scope should be extended to the thorough LA or

RA if the MS does not respond to the paging message within the time set by the

timer. The timer should have a second-level accuracy and is configurable by the

operator.

4. The operator can configure the repeated paging message subsequently sent by the

MSC or SGSN to be done so in the normal or precise mode.

5. If the MS is within a cell for which this feature is enabled but this feature is not

enabled for a cell adjacent to that cell, precise paging will be still applied to the cell

with this feature not enabled.

6. During the application of precise paging, the neighbor cell to which the paging

message sent is not subject to the limitation by the boundary of the location area or

routing area.



The above mentioned cell and its neighbor cells where services were implemented last

time are called “VPC” short for “visit paging cells”. To ensure better precise paging effects

are achieved, the cells where a subscriber usually use telephone services can be determined

by analyzing the subscriber’s moving behaviors and adopting a certain algorithm and are

called HPCs (home paging cell). Precise paging cells include VPC and HPC.

2.2 Correlation with Other Features

None



3 Technical Description

3.1 Determination of VPC and HPC

Configured based on the cell on the iOMCR, a VPC indicates a cell adjacent to the cell

where the last service exists. It can be a handover or reselection neighbor cell, or can be

configured additionally, but the configuration will be independent of whether the cell is

within the same location area or routing area as the original cell is when the cell which is

geographically near the cell where the last service is triggered is added into the VPC

provided that the cell must be one under the control of this BSC.

A HPC is selected from the cells where services have been triggered recently. Cells

where subscribers have appeared recently are recorded by IMSI on the CMP of the iBSC

(currently 16 cells are recorded). In case of insufficient available storage space, the cells

where last services were implemented earlier will be replaced.

As soon as the subscriber experiences the PS and CS services, the BSC records the cell

where such services run and determines the unified HPC through calculation. To record

the cell where the subscriber uses such services, the BSC must obtain the IMSI. For the

CS service, the IMSI cannot be obtained from the initial access message if the TMSI is

used and the MSC should send the IMSI to the BSC through the COMMON ID message.

For the PS service, the IMSI will be obtained from the downlink message sent by the SGSN.

3.2 Subscriber Data Management

Subscriber data storage refers to recording the information about the cells where the

subscriber uses services previously based on the IMSI. Such subscriber data is stored

on each CMP in a load shared manner, each CMP can store data of 100000 subscribers

and the earliest records will be replaced in case of insufficient available storage space.

The IMSI is mapped to the CMP module number in such way that a number ranging from

0 to 63 is obtained by calculating with the IMSI and then the number is mapped to the

CMP module. Under the circumstance that the module configurations are not changed,



the load sharing table is subject to no change. The module configurations change with

the mapping relationship and some previously recorded information will be lost.

3.3 Coordination with Core Network

1. Handling Repaging

When the BSC adopts precise paging and the MSC has implemented a multi-time paging

setting, the BSC needs to be coordinated to the parameter configurations of the core

network. The interval at which the MSC performs a paging should be set to be longer so

as to allow time for the BSC to perform another paging. When the BSC received the

messages, it will judge the paging as repaging performed from the core network if it

detects a paging message cached last time. The BSC determines whether the repaging

performed from the core network is done still in the precise mode or normal mode based

on the parameter configurations.

2. Range of Precise Paging

The CS paging may be performed from Port A or GB and usually covers the location area,

sometimes the entire BSC. The PS paging is performed from Port GB and mainly covers

the routing area and also may cover the entire BSC.

The VPC or HPC stored by the BSC may belong to different location areas/routing areas.

When the paging unit is location area/routing area, the BSC decides whether to send a

paging message to the HPC or VPC out of the current paging range based on the

CsOutAreaPag/PsOutAreaPag parameter. The BSC sends a paging message to a cell

out of the core network paging range due to the consideration that a few records about

the location area in the MSC are not accurate because the MS has not completed

location update or a location update failure temporarily occurred although the location

change will be informed to the new location area at the network side when the cell phone

is moved to another location area.

Precise paging is also suitable for the scenario where the entire BSC is to be paged. For

single-cell CS paging and paging performed to the BVC for the PS service, precise

paging is not used.



Precise paging and multiple paging operations performed by the BSC are more suitable

for the case where one location area belongs to one BSC because certainly precise

paging performed by one BSC will not be responded and thus paging traffic increase will

be result from the subsequent sending of common paging messages when one location

area belongs to two BSCs.

3.4 Support for Paging Hole Analysis

The principle for finding a paging hole is that: after a subscriber has been successfully

paged in a cell represented by a LAC which is assumed to be the cell where subscriber

resides, paging is failed once in that cell when the paging of that subscriber is not

responded; if the cell where the paging is responded is not the original cell, then the cell

where the subscriber resides is changed as the current cell and the paging is considered

to be successfully performed. When the subscriber leaves the LAC area, accordingly the

paging message will not be generated. Cells with poor paging effects can be calculated

by making long-term statistics following the above mentioned principle. Such results,

although of an estimation nature, can reflect the overall paging performance.

After the precise paging is implemented, the paging hole can be analyzed by

incrementing the counter as the cell where services were triggered for the subscriber is

recorded and whether the paging is responded is known. But, it should be noted that the

records about the subscriber’s location by the BSC are not complete and are not

appropriate for analyzing the paging hole for a location area crossing several BSCs.

The counter for the paging hole will not count until the time to the last services does not

exceed the PagHoleTimer. The counting method is as follows: if the paging is responded,

one paging to the cell where paging is responded is counted (paging has been

successfully performed once in this cell); if the paging is not responded, then one paging

which is performed in the cell where last services are triggered is counted once and is not

responded once.



3.5 Repaging

Currently, the core network and BTS can perform repaging. The core network will resend

a paging message if it has not received the paging response a certain period of time after

it has sends the paging message, while the BTS performs repaging during the idle time

regardless of whether the repaging will be responded. While supporting precise paging,

the BSC also provides the multiple searching feature which is similar to the repaging

feature of the core network. The maximum paging repeat time is controlled through the

CsPagingRepeatTime/PsPagingRepeatTime parameter. Multiple paging operations are

also not suitable for a location area crossing several BSCs.

3.6 Flow Control

If it is decided that the BSC does not support precise paging or multiple paging

operations from the time when the BSC has received the MSC paging message from

Port A or the SGSN paging message from Port Gb, then the MSC paging message or

SGSN paging message will be directly sent to the CMP module belonging to the target

cell is located and the CMP module sends the paging message to the relevant cells. If

the BSC supports precise paging or multiple paging operations, then the BSC obtains the

code of the cell where latest services are triggered through the IMSI. If the

PrecisepagUseHpc parameter is set to 1, then the BSC acquires the HPC list and

obtains the VPC list of the cells where last services are triggered through the

configuration data (the CsOutAreaPag/PsOutAreaPag parameter indicates that it is not

allowed to perform paging out of the core network paging range, then relevant cells will

be removed) and sends the paging messages to such cells and caches the same.

When the incoming paging is responded within a cell, then the cached paging messages

will be deleted. If the incoming paging is not responded, the paging will be performed

within the range required by the core network after the timer times out. If the system still

cannot reach any subscriber, then multiple paging operations may be performed based

on the parameter configurations. If the core network performs downcoming repaging,

then the BSC will process the repaging from the core network.



4 Parameters and Configurations

4.1 Parameter List

Table 4-1 Parameter List

SN Name Figure

1 PrecisePagSupport Figure 4-1

2 PrecisepagUseHpc Figure 4-1

3 CsRepagPrecise Figure 4-1

4 PsRepagPrecise Figure 4-1

5 CsOutAreaPag Figure 4-1

6 PsOutAreaPag Figure 4-1

7 CsPagingRepeatTime Figure 4-1

8 PsPagingRepeatTime Figure 4-1

9 CsPrecisePag Figure 4-1

10 PsPrecisePag Figure 4-1

11 VpcAgeTime Figure 4-2

12 PagWaitTime Figure 4-2

13 GGsmVpcRelationSeq Figure 4-3

14 refGGsmCell Figure 4-3

4.2 Parameter Configuration

1. On the Configuration Resource Tree window, double click BSC Precise Paging

Configuration under OMMR → Modify Area → Managed Element → GSM

Logical Configuration → Global Information Configuration to set such

parameters as Support Precise Paging, Use HPC for Precise Paging, Adopt

Precise Paging for repaging of Circuit Switched Service, Adopt Precise

Paging for repaging of Packet Switched Service, Allow Exceed area Precise

Paging for Circuit Switched Service, Allow Exceed area Precise Paging for

Packet Switched Service, Paging Repeat Time for Circuit Switched Service,




Paging Repeat Time for Packet Switched Service, etc on the BSC Precise

Paging Configuration tab, as shown in the figure below.

Figure 4-1 BSC Precise Paging Configuration Interface

2. On the Configuration Resource Tree window, double click Cell Precise Paging

Configuration under OMMR → Modify Area → Managed Element → GSM

Logical Configuration → Global Information Configuration → Cell Information

Configuration to set such parameters as Adopt Precise Paging for Circuit

Switched Service, Adopt Precise Paging for Packet Switched Service, VPC

Age Time, Paging Hole Timer, etc on the Cell Precise Paging Configuration tab,

as shown in the figure below.



Figure 4-2 Cell Precise Paging Configuration Interface

3. On the Configuration Resource Tree window, double click Visit Paging Cell under

OMMR → Modify Area → Managed Element → GSM Logical Configuration →

Global Information Configuration → Cell Information Configuration →

adjacent Relation Configuration to set such parameters as Parent DN, Visit

Paging Cell ID, VPC Id, DN of GgsmCell, etc on the Visit Paging Cell tab, as

shown in the figure below.



Figure 4-3 Visit Paging Cell configuration Interface



5 Related Counters and Alarms

5.1 Related Counters

Table 5-1 Counters List

Counter ID Name

C901110041 Number of CS Precise Paging

C901110042 Number of CS Precise Paging Response

C901110043 Number of CS First Paging

C901110044 Number of CS First Paging Response

C901110045 Number of CS Second Paging

C901110046 Number of CS Second Paging Response

C901110047 Number of CS Third Paging

C901110048 Number of CS Third Paging Response

C901110049 Number of PS Precise Paging

C901110050 Number of PS Precise Paging Response

C901110051 Number of PS First Paging

C901110052 Number of PS First Paging Response

C901110053 Number of PS Second Paging

C901110054 Number of PS Second Paging Response

C901110055 Number of PS Third Paging

C901110056 Number of PS Third Paging Response

C901110057 Number of CS Precise Paging for Last Service in This Cell

C901110058 Number of CS Precise Paging No Response for Last Service in This

Cell

C901110059 Number of CS First Paging for Last Service in This Cell

C901110060 Number of CS First Paging No Response for Last Service in This

Cell

C901110061 Number of CS Second Paging for Last Service in This Cell

C901110062 Number of CS Second Paging No Response for Last Service in This

Cell

C901110063 Number of CS Third Paging for Last Service in This Cell




C901110064 Number of CS Third Paging No Response for Last Service in This

Cell

C901110065 Number of PS Precise Paging for Last Service in This Cell

C901110066 Number of PS Precise Paging No Response for Last Service in This

Cell

C901110067 Number of PS First Paging for Last Service in This Cell

C901110068 Number of PS First Paging No Response for Last Service in This

Cell

C901110069 Number of PS Second Paging for Last Service in This Cell

C901110070 Number of PS Second Paging No Response for Last Service in This

Cell

C901110071 Number of PS Third Paging for Last Service in This Cell

C901110072 Number of PS Third Paging No Response for Last Service in This

Cell

C901110073 Number of CS Precise Paging (Paging Hole Search)

C901110074 Number of CS Precise Paging No Response (Paging Hole Search)

C901110075 Number of CS First Paging (Paging Hole Search)

C901110076 Number of CS First Paging No Response (Paging Hole Search)

C901110077 Number of CS Second Paging (Paging Hole Search)

C901110078 Number of CS Second Paging No Response (Paging Hole Search)

C901110079 Number of CS Third Paging (Paging Hole Search)

C901110080 Number of CS Third Paging No Response (Paging Hole Search)

C901110081 Number of PS Precise Paging (Paging Hole Search)

C901110082 Number of PS Precise Paging No Response (Paging Hole Search)

C901110083 Number of PS First Paging (Paging Hole Search)

C901110084 Number of PS First Paging No Response (Paging Hole Search)

C901110085 Number of PS Second Paging (Paging Hole Search)

C901110086 Number of PS Second Paging No Response (Paging Hole Search)

C901110087 Number of PS Third Paging (Paging Hole Search)

C901110088 Number of PS Third Paging No Response (Paging Hole Search)

5.2 Related Alarms

This feature has no related alarm.



6 Engineering Guide

6.1 Application Scenario

This feature is usually used as required by the operator when CCCH channels need to be

saved in case of a large paging volume, but it is recommended to disable the precise

paging feature for cells with subscribers moving quickly. This is because usually the

subscriber is located in the cells with subscribers moving quickly (cells covering highway,

or those along the railway line) when paged but is probable that the subscriber has

moved to an area out of the coverage by the cell and its VPC and HPC when paged for

the next time, and at this time it is greatly probable that precise paging will be failed and

the effects of precise paging will not be achieved.

6.2 Configuration Description

PrecisePagSupport The precise paging feature is usually used as required by the

operator when CCCH channels need to be saved in case of a large paging volume.

PrecisepagUseHpc It may be considered that the HPC should be used for such

areas where subscribers move seldom as the office area, residential area, etc.

CsRepagPrecise This feature is mainly set as required by the operator and it may

be considered that this feature should be enabled when the subscriber can tolerate

longer connection time.

PsRepagPrecise This feature is mainly set as required by the operator. It may be

considered that this feature should be enabled when the PS paging is performed for

non-real-time services or real-time services can tolerate longer connection time.

CsOutAreaPag Usually this feature does not need to be enabled. It may be enabled

when the BSC cannot obtain the IMSI and cannot record the subscriber’s location upon

location change.



PsOutAreaPag Usually this feature does not need to be enabled. It may be enabled

when the BSC cannot obtain the IMSI and cannot record the subscriber’s location upon

routing area change.

CsPagingRepeatTime It may be set that multiple paging operations can be applied

on the BSC usually when the core network does not use the multiple paging operations.

PsPagingRepeatTime It may be set that multiple paging operations can be applied

on the BSC usually when the core network does not use the multiple paging operations.

CsPrecisePag It may be considered that the precise paging feature should be

disabled for the cells with subscribers moving quickly.

PsPrecisePag It may be considered that the precise paging feature should be

disabled for the cells with subscribers moving quickly.

VpcAgeTime This parameter may be usually set to be permanently valid. In case of

other values, the subscriber moving speed should be considered and how long the

subscriber can move out of the VPC coverage as configured should be estimated.

PagWaitTime This parameter should be set by considering the configurations of the

paging block and the transmission delay of the Abis port.

VpcSiteId/VpcBtsId The VPC indicates a cell around the cell where the last service

exists. In the case that few VPCs are configured, the system may not reach any subscriber

through precise paging and cannot reach any subscriber until the subsequent normal

paging has been performed. In the case that many VPCs are configured, many paging

messages are sent through precise paging. Which cells should be configured to be VPCs

should be determined referring to the cell coverage and subscriber moving speed.

6.3 Network Impact

In the case of a large number of subscribers and large PS traffic load in a location area,

there will be a great number of paging messages and immediately assigned messages

on the CCCH channel and consequently congestion easily arises. One solution to this

situation is to configure more CCCH channels, but this solution will reduce the available

service channels. Another solution is to enable the precise paging feature.



After precise paging is enabled, the system performs paging within some cells where it is

more probable that the system can reach a subscriber and then performs paging within

the range required by the core network in case of a failure to reach any subscriber. As it

is greatly probable that the system can reach a subscriber within a small range, paging

messages are decreased and thus this can save CCCH channels and increase

configuration service channels.

But due to the fact that the system may not reach a cell phone in precise paging it needs

to further perform normal paging to reach that cell phone and this may extend the

response delay. However, this situation can be avoided as possible as we can by

appropriately selecting cells with precise paging enabled, e.g. cells covering highways

where subscribers move quickly. In such cells, it is greatly probable that the system

cannot reach any subscriber upon the first paging if precise paging is enabled for them.

So, it is better to disable the precise paging feature.

Enabling this feature will have no impact over the capacity of the BSC.

7 Abbreviation

HPC Home Paging Cell

VPC Visit Paging Cell

8 Reference Document

None

Documents

Precise Paging Feature Guide