路测层3信令分析 下载本文

Timing Advance: n/a RX Quality Sub: n/a Local Area Code: 14101 MS Power: n/a Cell ID: 41101

16 Layer 3 Uplink 18:52:20.907 FACCH CONNECT

被叫用户听到振铃作出应答后,将发送给MSC接通CONNECT消息,MSC再收到此消息后,接通全部链路,用户端到端传输全部建立.

17 Layer 3 Downlink 18:52:21.048 FACCH CONNECT ACKNOWLEDGE 按照集团公司测试规范,此时属于正式接通.

18 Layer 3 Downlink 18:54:07.660 FACCH DISCONNECT 由于是主叫挂机,系统通知被叫拆线。 Cause (16): Normal call clearing

19 Layer 2 Uplink 18:54:07.664 FACCH RR-RESP 20 Layer 2 Uplink 18:54:07.731 FACCH I-CMD 21 Layer 3 Uplink 18:54:07.731 FACCH RELEASE

但此时呼叫并未完全结束,系统与移动台之间需要保持一定的任务,如送收费指示等。当系统认为与移动台之间的连接已无必要时,被叫移动台向系统发出release消息. 22 Call Disconnect 18:54:07.731 TOM注释,

Status:Normal disconnect Phone Number: n/a Time From Attempt: 108 CC Cause: 16

23 Layer 3 Downlink 18:54:07.858 FACCH RELEASE COMPLETE

系统收到被叫移动台发送的RELEASE消息后,会向被叫移动台发出RELEASE COMPLETE表示呼叫已经结束。

24 Layer 2 uplink 18:54:07.858 FACCH UI-CMD 确认帧.

25 Layer 3 Downlink 18:54:07.978 FACCH CHANNEL RELEASE M RR Cause (hex data: 00) RR Cause value (0): Normal event

MSC收到被叫移动台UA确认消息后,向BSC发出清除命令CLEAR COMMAND,释放所有信令链路,该消息中携带此次呼叫清除原因,到此呼叫连接CC层释放完成。BSC收到清除命令后,一方面向移动台

发出释放信道(CHANNEL RELEASE)消息,同时要求移动台返回空闲模式。 26 Layer 2 Uplink 18:54:08.017 FACCH DISC-CMD

被叫移动台收到CHANNEL RELEASE后,拆除上行信令链路,即拆除上行SACCH随路信令的测量报告,移动台向BTS发出DISC消息.并且返回CCCH空闲模式. §2.3开机位置更新信令流程

1 Location Update Attempt 18:52:12.464 2 Location Update Accepted 18:52:12.464 Old LAC: n/a New LAC: 14101 Mobile Country Code: 460 Mobile Network Code: 0

3 Service Information 18:52:12.464 Service received §2.4跨越LAC区位置更新信令流程

Location updating: successful case

1 Cell Reselection 10:51:52.245 进行了小区选择 Old Cellular System: GSM 900 Old LAC: 14129

Old Cell Identification: 42881 New Cellular System: GSM 900 New LAC: 14085

New Cell Identification: 1091

2 Layer 2 Uplink 10:51:53.593 RACH RANDOM_ACCESS_BURST 3 Layer 3 Uplink 10:51:53.593 RACH CHANNEL REQUEST 申请信道得作用是用于位置更新(代号0C) M Establishment Cause (hex data: 0c)

Meaning of establishment cause: Location updating and the network sets NECI bit to 1 4 Layer 3 Downlink 10:51:53.656 CCCH IMMEDIATE ASSIGNMENT 指配命令中,包含信道类别,如话音数据指示,信道速率和类别以及话音解码算法 5 Layer 3 Uplink 10:51:53.888 SDCCH LOCATION UPDATING REQUEST

该消息中携带有移动台TMSI和LAC号码且注明了申请信道得作用是用于位置更新.MSC收到此消息后,

将此消息发给VLR,VLR将更新移动台得位置信息,存储新的LAC号码.并向移动台发出一个新的TMSI, M Location Updating Type (hex data: 0)

Location updating type: Normal location updating No follow on request pending

M Location Area Identification (hex data: 64f00037 05) MCC digits: 460 MNC digits: 0 LAC: 14085

M Mobile Identity (hex data: 05f475d5 7145) Type of identity: TMSI/P-TMSI Identity digits: 75d57145

6 Location Update Attempt 10:51:53.888

7 Layer 3 Downlink10:51:54.325 SDCCH AUTHENTICATION REQUEST 8 Layer 3 Uplink 10:51:55.064 SDCCH AUTHENTICATION RESPONSE 7-8是进行鉴权及鉴权响应

9 Layer 3 Downlink 10:51:55.266 SDCCH IDENTITY REQUEST

若网络中移动台TMSI无法被系统所识别,则移动台需提供其IMSI,在TMSI重分配启动之前,应先启动识别程序,请求移动台提供其IMSI号。网络向移动台发送识别请求。 M Identity Type (hex data: 3) Identity type: IMEISV

10 Layer 3 Uplink 10:51:55.535 SDCCH IDENTITY RESPONSE

在收到识别请求后,移动台发起识别响应来向网络提供其IMSI号,在此程序完成之后,进入TMSI再分配过程。

M Mobile Identity (hex data: 09337590 08202195 10f4) Type of identity: IMEISV

Identity digits: 3570980021259014 9-10是进行设备号IMEI识别请求及响应.

11 Layer 3 Downlink 10:51:55.973 SDCCH LOCATION UPDATING ACCEPT 系统向移动台发出位置更新的消息. 12 Location Update Accepted 10:51:55.973 Old LAC: 14085 New LAC: 14129

Mobile Country Code: 460 Mobile Network Code: 0

13 Layer 3 Uplink 10:51:56.249 SDCCH TMSI REALLOCATION COMPLETE 移动台向网络发出TMSI重新分配完成消息.

14 Layer 3 Downlink 10:51:56.443 SDCCH CHANNEL RELEASE 15 Layer 2 Uplink 10:51:56.712 SDCCH DISC-CMD

14-15是网络接受到 重新分配完成消息后,向移动台发出信道释放消息,移动台给予响应,并且返回到空闲模式.

§2.5切换信令流程 §2.5.1同步切换信令流程

Handover to a finely synchronized cell, successful case Measurement report(MS-BTS-BSC) Physical context request Physical context confirm 查询时间提前量和功率控制 Channel activation

BSC收到测量报告以后,判断需要将手机切换到其它小区,则BSC向目标小区发出信道激活信息 Channel activation ack Assignment command SABM

Establish indication UA

Assignment complete(MS-BTS-BSC)

1 Layer 3 Downlink 18:53:20.814 FACCH HANDOVER COMMAND 2 Handover Attempt 18:53:20.814

3 Layer 2 Uplink 18:53:20.937 FACCH SABM-CMD

4 Layer 3 Uplink 18:53:21.060 FACCH HANDOVER COMPLETE RF channel release 信道释放 RF channel release ack

5 Handover Success 18:53:21.060

上边44-48是一个BCF下不同小区之间的同步切换过程,由于是同步切换TA值便可以用以前的。在44条中指名,可以看出,同步切换没有发送物理消息,这也是两者之间的区别。 §2.5.2非同步切换信令流程

Handover to a non-synchronized cell, successful case

1 Layer 3 Downlink 18:53:13.286 FACCH HANDOVER COMMAND

BSC收到BTS2的激活信息后,BSC通过BTS1发送HANDOVER COMMAND给移动台,并启动T3103定时器,切换指令中含有在新信道上传输的所有特征信息和移动台连接所需的数据,而且他还指示了该切换是同步切换还是非同步切换。同步切换是发生在同一基站的不同小区间,移动台计算时间提前两来完成同步,而非同步切换是发生在不同基站之间的小区间,通过系统下发的物理消息和下发的TA值来完成手机与基站之间的同步。

M Cell Description 目标小区信道描述 BCC: 2 NCC: 1

BCCH carriers absolute RF channel: 92 M Description of the first channel,原信道描述 Timeslot: 2

Channel type: TCH/H + ACCHs Subchannel: 0

Training sequence code: 2

Hopping channel: RF hopping channel MAIO: 0 HSN: 44

M Power Command (hex data: 05)

ATC: Sending of Handover access is mandatory FPC: not in use Power level: 5

O Synchronization Indication (hex data: d0)

Synchronization indication: Non-synchronized 非同步切换 C Cell Channel Description

2 Handover Attempt 18:53:13.286 Handover between cells Current Cellular System: GSM 900 当前小区情况描述