Chapter 8 Handover信令
经典案例-规范PLMN配置提升竞合站点切换成功率
规范PLMN配置提升竞合站点切换成功率【摘要】电信与联通共建共享站点，通过在本方基站开通对方小区的方式，进行资源共享，节约了站址资源。
共享站点只接入一方网管，谁主建谁监管的原则进行维护。
由于同时接入两个运营商网络，因此共享站点会配置两个PLMN，在邻区配置也需要进行特殊设置，才能确保非共享站点与共享站点之间正常切换。
【关键字】联通竞合切换 PLMN【故障现象】日常KPI监控发现，部分站点切换失败较多，且不局限主设备区，在华为、诺基亚区域均存在。
一、诺基亚设备区桥头集淝光村-906524_50小区切换准备失败较多。
通过点对点切换统计分析，大量切换准备失败，目标小区为LTZJ-肥东大郭村-167985下面的小区，cellid为136\137，LTZJ-肥东大郭村-167985为联通主建共享基站。
切换准备失败的目标小区为联通共享给电信的小区，往电信其它小区切换均正常。
图1：桥头集淝光村-906524切换准备失败二、华为设备区BZ-市区-芦庙陈楼-HFTA-154671-180，指标监控发现S1切换成功率偏低。
图2：BZ-市区-芦庙陈楼-HFTA-154671-180小区S1切换成功率低【告警信息】一、Sitemanager登录基站查看桥头集淝光村-906524_50小区状态正常，无告警。
图3：桥头集淝光村-906524告警二、网管查询BZ-市区-芦庙陈楼-HFTA-154671-180扇区告警、其他指标均正常，网络拓扑正常，只是S1切换成功率低。
图4：BZ-市区-芦庙陈楼-HFTA-154671-180告警分析【原因分析】一、切换流程分析切换整个过程可分为切换准备阶段、切换执行阶段，切换准备阶段为信道资源的预分配，待目标基站预留好相应资源后，由源基站下发切换命令给MS，完成后续切换接入目标小区，为切换执行阶段。
按照涉及的网元关系，切换可以分为三大类：eNB内切换、eNB间X2切换及eNB间S1切换。
图5：S1切换信令图完整的S1切换流程如下：1、eNB发送测量控制，UE根据当前小区的测量控制信息，将符合切换门限的小区进行上报；2、源小区在收到测量报告后通过S1接口向MME发送handoverrequired信令，MME向目标小区发送HO Request申请资源，此统计点为切换准备请求信令点；3、目标小区准备好相应资源，并将终端的接纳信息以及其它配置信息反馈给MME，MME向源小区下发handover command，切换准备成功；4、源小区将目标小区的接纳信息及配置信息发给终端，告知终端目标小区已准备好终端接入，重配消息里包含目标小区的测量控制；HO_Attempt在此计数；5、终端使用重配消息里的接入信息接入目标小区，核心侧完成路由切换后，目标小区通知源小区释放资源，切换成功，此时源小区的HO_Success统计在此计数切换准备失败信令点：源小区向MME发送handoverrequired，但MME未回复handover command；可能原因及解决方案：①目标小区故障-----排障②目标小区资源不足、拥塞----负荷均衡、区域扩容③数据配置错误—检查数据二、信令分析1、桥头集淝光村LTZJ-肥东大郭村-167985为联通主建共享基站，电信网管无法查询该站的KPI情况，但从周边小区切换分析，撮镇锦绣花园-906389往LTZJ-肥东大郭村-167985的切换正常。
第八章移动交换详解
参考点(接口)
1. Sm接口——人机接口 2. Um接口——MS与BS之间的接口 3. A接口——BS与MSC之间的接口 4. B接口——MSC与 VLR之间的接口 5. C接口——MSC与HLR之间的接口 6. D接口——HLR与VLR之间的接口 7. E接口——MSC与MSC之间的接口 8. F接口——MSC与EIR之间的接口 9. G接口——VLR与VLR之间的接口 以上各接口除Sm和Um之外，其它接口称为
HLR
“位置登记请求” “更新位置登记” 询问“MS的IMSI”
“询问IMSI”响应
查询“MS有关参数”
“更新登记请求”
“位置登记请求”
确认
确认
“查询有关参数”响应 “位置信息注销”
8.2.2 移动呼叫处理
与传统的程控交换机相比，移动呼叫有如下特点：
呼叫处理：MSC对MS不进行用户扫描、送拨号音、
漫游也称出游，它的意义是MS
脱离了本管区的范围移动到其 他管区中去了，当其他用户呼 叫这个漫游的MS时，仍拨它原 来的局号和电话号码。
漫游服务包括位置更新、呼叫
转移和呼叫建立三个过程。
1.位置更新
(3)
(3)
(4)
MS
(2)
BS1
(7)
MSC1
(6)
(6)
(5)
(1)
1区
VLR1
2区
MSC2
MS
呼出的MS或呼入的MS分配业务信道和信令信道。 一般每个小区都配有固定的业务信道，该小区信道 全忙时，在条件许可的情况下可以借用相邻小区的 信道。
开机
MS不能接收寻 呼信道消息
MS未收到寻呼 消息应答
初始化 MS已捕获系统定时
中国移动--LTE信令流程
RLC层依然提供TM/UM /AM三种传输模式
E-UTRAN接口通用协议模型
基本概念
接口功能
LTE接口通用模型
适用于E-UTRAN相关的所有接口，即S1和X2接口 控制面和用户面相分离，无线网络层与传输网络层相分离 无线网络层：实现E-UTRAN的通信功能 传输网络层：采用IP传输技术对用户面和控制面数据进行传输
LTE信令流程
研究院无线所 2010年12月
主要内容
基本概念
网络架构 协议栈结构 接口功能 无线网系统消息 UE的工作模式与状态 无线承载的分类 UE标识
无线网基本信令流程
随机接入 寻呼 RRC连接建立、重配、重建 立、释放 测量
端到端业务建立/释放相 关流程
Attach流程 Detach流程 Service Request过程 专用承载建立流程 专用承载修改流程 专用承载释放流程
UDP/IP之上的GTP-U用来传输S-GW与 eNB之间的用户平面PDU
S1用户面主要功能为:
在S1接口目标节点中指示数据分组所属 的SAE接入承载； 移动性过程中尽量减少数据的丢失；
错误处理机制；
MBMS支持功能； 分组丢失检测机制；
X2接口协议栈
X2接口
基本概念
接口功能
LTE系统X2接口的定义采用了与S1接口 一致的原则
EPS Bearer
External Bearer
E-RAB
Radio Bearer
S1 Bearer
S5/S8 Bearer
Radio
S1
S5/S8
Gi
无线承载分类
GSM信令详解(完整版)
位置更新
MAP B MAP D VLR
BSSAP A MSC
HLR/AC 来访IMSI 3、鉴权参数请求(IMSI)
4、回送鉴权参数(IMSI,KC,S，R)
鉴权成功后重新分配TMSI,存储 新位置区LAI和CKSN 7、更新位置
5、 6、鉴权响应
位置更新
MS进入新位置区，新旧位置区在同一MSC覆盖区域内，即VLR并未改变
3、 4、鉴权响应（S）
3、 4、
4、SRES 5、启动加密(KC) 6、前传新TMSI 7、位置更新接受
鉴权成功后重新 分配TMSI，存储新位置 LAI和CKSN
8、 开 始 加 密 传 送 9、加密模式完成
8、加密模式命令（KC） 9、
12/84 12/43
基本信令流程
移动始发短消息的流程图。
MS MSC 接入请求过程同主叫过程 sms_message_transfer map_send_info_for_mo_smc map_forward_sms VLR HLR SMS_IWMSC
短消息流程
SC
sms_message_transfer
BSSAP A
MAP B MSC VLR
MAP D
HLR
AUC
业务请求（CM-SERV-REQ） CM-业务请求（CONN-REQ） CON-CONF(接续确认) CC
处理接入请求（PROC ACCES REQ） 鉴权参数请求 鉴权参数响应
AUT-INFO-REQ AUT-INFO-PROY
鉴权请求 鉴权响应
MSCa
MSCb
A Um
VLRb BSS2
信令_汉语注释版
*CC层的主要功能为建立、维持和释放呼叫：a、有关呼叫建立的信息（Call Establishment）:Alerting：告警信息，上下行。
从网络到主叫移动台或从被叫移动台到网络，用来指示被叫手机启动告警（即回铃音）。
包括进展指示及用户信息等Call confirmed：呼叫确认，该信息由被叫移动台发出，用来确证收到呼叫请求；Call proceeding：呼叫进程，该信息由网络发向主叫移动台，指示被请求的呼叫建立信息已经被接收,不会再接收更多的呼叫建立信息。
Connect：连接，从网络到主叫移动台或从被叫移动台到网络，用来指示连接被接受；Connect Acknowledge：连接确认，从网络到被叫移动台或主叫移动台到网络，指示移动台得到一个呼叫（连接完成）；Energency Setup：紧急建立，由移动台发出，用来启动一个紧急呼叫的建立；Progress：进展，从网络到移动台，指示呼叫的进程；Setup：建立，上下行，指示启动呼叫建立；b、呼叫信息状态（Call Information Phase）Modify：修改，上下行，请求改变呼叫的承载能力；4G Modify Complete：修改完成，指示对呼叫承载能力修改的完成；Modify Reject：修改拒绝，上下行，指示改变呼叫的承载能力请求的失败；User Information：用户信息,由移动台发向网络来传输信息到远端用户或由网络发向移动台传输从远端用户来的信息。
c、呼叫清除（Call Clearing）MOTODisconnect：断连，从移动台到网络请求清除端到端的连接，或从网络到移动台指示端到端的连接已经被清除了；Release：释放，上下行,指示发该信息的设备将要释放TI(处理识别码),接收到4G该信息的设备等发送释放完成信息后释放TI(处理识别码)bbs. ),接收到该信息的设备将要释放TI(处理识别码)d、与附加业务有关的呼叫（Call Related SS）Facility：设施Hold：保持Hold Acknowledge：保持确认vHold Reject：保持拒绝Retrieve：恢复通Retrieve Acknowledge：恢复确认Retrieve Reject：恢复拒绝e、其它信息bbs.4Congestion Control：拥塞控制，上下行，指示在传输用户信息时建立和中止流量控制。
GSM信令流程英文
Release confirm
RF Channle release
RF Channel release ack Alerting
Connect
Connect acknowledge
MSC Assignment Request
Assignment Complete
主 MS 叫 流 程 之 三
BTS
BSC
SABM(loc_upd_req)
establish indication
Complete Layer 3 Info.
UA(loc_upd_req)
Authentication request
Authentication response
Cipher Mode Command
Encryption command
寻呼(Paging)
• IMSI • TMSI(可选项) • Cell Identifier List(规定寻呼命令发送范围)
寻呼命令(Paging command)
• Paging group • MS Identity
寻呼请求(Paging request)
• Page mode • Channel needed(信道类型) • Mobiles Identity
SABM(pag_resp)
establish indication
Complete Layer 3 Info.
UA(pag_resp)
Authentication request
Authentication response
Cipher Mode Command
Encryption command
建立(Setup)
BSS试题及答案
填空：1.GSM的频段为890－960MHZ，信道间隔为200khz，双工间隔为45mhz。
①2.bss包括bts、bsc、tc。
①3.移动通信系统目前采用__FDMA__、_____TDMA和_CDMA____三种多址方式，GSM主要采用TDMA_____多址方式。
①4.GSM系统主要结构由BSS____、___NSS_、__OSS__三个子系统和____MS_组成。
①5.小区最小接入电平是由参数控制；（RXP）①6.gsm采用 gmsk 调制方式，B*T＝ 0.3 ②7.gsm采用基带跳频和射频跳频②8.网络质量的监测有三种方法:网管监测、DT测试、用户投诉. ②9.网络质量循环图中的配置分析是什么含义：现网数据和网络规划设计数据对比。
②10.Internal inter cell HO 意思是：BSC internal. ②11.NOKIA METROSITE BASE STATION 的容量最大可配置4个TRXS. ②12.GPRS手机的移动性管理状态有那三种:IDLE,READY,STANDBY. ②13.GPRS附着和路由区更新总是由MS启动. ②14.GPRS移动台的类型有A类,B类,C类. ②15.BSS现网升级到能使用GPRS功能,需要为每个BCSU配备一个PCU单元. ②16.天线的增益单位dBd和dBi之间的换算关系为:0(dBd)=2.15(dBi).②17.1 超高帧等于2048x51x26 TDMA 帧。
②18.做一个4+5站的集成时，需在BSC中建1个BCFs，2个BTSs和9个TRXs 。
在建LAPD信令时，BCFSIG的SAPI为62，TRXSIG的SAPI为0，TRXSIG的TEI等于TRX的逻辑地址。
②19.在BSC中，BCSU单元用来处理信令，它的冗余方式是N+1,每个单元能处理4 CCS7，16 TRXSIG 和 16 BCFSIG.. ②20.在11种逻辑信道中，FCCH用于纠正MS的频率，BCCH用于广播小区信息，SACCH用于传送功率控制信令，FACCH用于传送Handover信令。
华为常见行为的信令流程
1. 1位置更新流程在GSM系统中有三个地方需要知道位置信息，即HLR、VLR和MS。
当这个信息发生变化时，需要保持三者的一致，由位置更新流程实现。
位置更新流程是位置管理中的主要流程，总是由MS发起。
位置更新流程是一个通用流程，在如下三类位置更新流程中要使用到：正常位置更新、周期性位置更新、IMSI附着位置更新流程。
正常位置更新用于更新网络侧对于MS的位置区信息，LOCATION UPDATING REQUEST消息中包含位置更新流程的类型信息。
在网络侧VLR判定MS为未知用户时，会启动正常位置更新流程，作为MM连接建立请求的响应。
为限制位置更新尝试次数，位置更新失败时要使用位置更新attempt counter计数器。
在MS 开机或SIM卡刚插入时，该计数器清零。
MS 中要保持一个"forbidden location areas for roaming"表和一个"forbidden location areas for regional provision of service"表。
MS 关机或SIM卡拔出时，将这两个表删除。
当MS收到位置更新拒绝消息，其原因值为"Roaming not allowed in this location area"或"Location Area not allowed〃时，从BCCH上收到的LAI信息触发位置更新请求的LAI要加到相应的表中。
这两个表的容量至少要有10个表项，当表项数目超过表的容量时，最早的表项内容删除。
成功的进行位置更新后，MS在SIM卡中置UPDATED状态位（UPDATED状态表明最后一次位置更新请求成功，同时此时LAI、TMSI，加密的密钥和加密序列号都应该保存在SIM卡中），并存储新的位置区信息。
正常位置更新、周期性位置更新和IMSI附着位置更新流程基本相同（不同之处在下面各小节中详细描述），流程如下图：（1）MS在空中接口的接入信道上向BTS发送Channel Request （该消息内含接入原因值为位置更新）；（2）BTS 向 BSC 发送 Channel Required 消息；(3)BSC收到Channel Required后，分配信令信道，向BTS发送Channel Activation；(4)BTS收到Channel Activation后，如果信道类型正确，则在指定信道上开功率放大器，上行开始接收信息，并向BSC发送Channel Activation Acknowledge；(5)BSC 通过 BTS 向 MS 发送 Immediate Assignment Command；⑹MS发SABM帧接入；(7)BTS回UA帧进行确认；(8)BTS 向 BSC 发 Establishment Indication，该消息中包含了 Location Update Request消息内容；(9)BSC 建立 A 接口 SCCP 链接，向 MSC 发送 Location Update Request，该消息中包含了当前小区的CGI信息；(10)MSC向BSC回链接确认消息；(11)MSC向MS回位置更新接受消息，表明位置更新成功；(12)在网络侧拒绝本次位置更新时，网络侧下发消息给MS；(13)若MSC侧选择“位置更新时分配TMSI”为否，则在位置更新的过程中，MS 没有“TMSI Reallocation Complete”消息的上报。
LTE 切换信令流程
Handover1 Intra-E-UTRAN handover1.1 X2-based handover1.1.1 GeneralThese procedures are used to hand over a UE from a source eNodeB to a target eNodeB using the X2 reference point. In these procedures the MME is unchanged. Two procedures are defined depending on whether the Serving GW is unchanged or is relocated. In addition to the X2 reference point between the source and target eNodeB, the procedures rely on the presence of S1-MME reference point between the MME and the source eNodeB as well as between the MME and the target eNodeB.The handover preparation and execution phases are performed as specified in TS 36.300 [5]. If emergency bearer services are ongoing for the UE handover to the target eNodeB is performed independent of the Handover Restriction List. The MME checks, as part of the Tracking Area Update in the execution phase, if the handover is to a restricted area and if so MME releases the non-emergency bearers as specified in clause 5.10.3.If the serving PLMN changes during X2-based handover, the source eNodeB shall indicate to the target eNodeB (in the Handover Restriction List) the PLMN selected to be the new Serving PLMN.When the UE receives the handover command it will remove any EPS bearers for which it did not receive the corresponding EPS radio bearers in the target cell. As part of handover execution, downlink and optionally also uplink packets are forwarded from the source eNodeB to the target eNodeB. When the UE has arrived to the target eNodeB, downlink data forwarded from the source eNodeB can be sent to it. Uplink data from the UE can be delivered via the (source) Serving GW to the PDN GW or optionally forwarded from the source eNodeB to the target eNodeB. Only the handover completion phase is affected by a potential change of the Serving GW, the handover preparation and execution phases are identical.If the MME receives a rejection to a NAS procedure (e.g. dedicated bearerestablishment/modification/release; location reporting control; NAS message transfer; etc.) from the eNodeB with an indication that an X2 handover is in progress (see TS 36.300 [5]), the MME shall reattempt the same NAS procedure either when the handover is complete or the handover is deemed to have failed, except in case of Serving GW relocation. The failure is known by expiry of the timer guarding the NAS procedure.If during the handover procedure the MME detects that the Serving GW needs be relocated, the MME shall reject any PDN GW initiated EPS bearer(s) request received since handover procedure started and shall include an indication that the request has been temporarily rejected due to handover procedure in progress. The rejection is forwarded by the Serving GW to the PDN GW, with the same indication.Upon reception of a rejection for an EPS bearer(s) PDN GW initiated procedure with an indication that the request has been temporarily rejected due to handover procedure in progress, the PDN GW start a locally configured guard timer. The PDN GW shall re-attempt, up to a pre-configured number of times, when either it detects that the handover is completed or has failed using message reception or at expiry of the guard timer.If the MME receives a rejection to a UE Context Modification Request message with a CS Fallback indicator from the eNodeB with an indication that an X2 handover is in progress, the MME shall resend a UE Context Modification Request message with CS Fallback indicator to the target eNodeB when the handover is complete or to the source eNB when the handover is deemed to have failed.1.1.2 X2-based handover without Serving GW relocationThis procedure is used to hand over a UE from a source eNodeB to a target eNodeB using X2 when the MME is unchanged and decides that the Serving GW is also unchanged. The presence of IP connectivity between the Serving GW and the source eNodeB, as well as between the Serving GW and the target eNodeB is assumed.Figure 1.1.2-1: X2-based handover without Serving GW relocation NOTE 1: For a PMIP-based S5/S8, procedure steps (A) are defined in TS 23.402 [2].1. The target eNodeB sends a Path Switch Request message to MME to inform that the UE haschanged cell, including the TAI+ECGI of the target cell and the list of EPS bearers to be switched.If the target cell is a CSG cell , the target eNodeB includes the CSG ID of the target cell in PathSwitch Request message. If the target cell is in hybrid mode, it includes the CSG ID of the target cell and CSG Access Mode set to "hybrid" in the Path Switch Request message. The MMEdetermines the CSG membership based on the CSG ID and CSG Access Mode received from the target eNodeB.The MME updates the User CSG information based on the CSG ID and CSG Access Mode received from the target eNodeB and CSG membership if one of the parameters has changed.NOTE 2: X2 handover between HeNBs is possible when the handover is between closed/hybrid access HeNBs having the same CSG ID or when the target HeNB is an open access HeNB.The MME determines that the Serving GW can continue to serve the UE2. The MME sends a Modify Bearer Request (eNodeB address(es) and TEIDs for downlink user planefor the accepted EPS bearers, ISR Activated) message per PDN connection to the Serving GW for each PDN connection where the default bearer has been accepted by the target eNodeB. If the PDN GW requested UE's location info, the MME also includes the User Location Information IE in this message. If the UE Time Zone has changed, the MME includes the UE Time Zone IE in thismessage. If the Serving Network has changed, the MME includes the new Serving Network IE in this message. If ISR was activated before this procedure, MME should maintain ISR. The UE is informed about the ISR status in the Tracking Area Update procedure. If the Serving GW supports Modify Access Bearers Request procedure and if there is no need for the SGW to send the signalling to the PGW, the MME may send Modify Access Bearers Request (eNodeB address(es) and TEIDs for downlink user plane for the accepted EPS bearers, ISR Activated) per UE to the Serving GW to optimize the signalling.If the PDN GW requested UE's User CSG information (determined from the UE context), the MME includes the User CSG Information IE in this message if the User CSG Information has changed.The MME uses the list of EPS bearers to be switched, received in step 1, to determine whether any dedicated EPS bearers in the UE context have not been accepted by the target eNodeB. The MME releases the non-accepted dedicated bearers by triggering the bearer release procedure as specified in clause 5.4.4.2. If the Serving GW receives a DL packet for a non-accepted bearer, the Serving GW drops the DL packet and does not send a Downlink Data Notification to the MME.If the default bearer of a PDN connection has not been accepted by the target eNodeB and there are multiple PDN connections active, the MME shall consider all bearers of that PDN connection as failed and release that PDN connection by triggering the MME requested PDN disconnectionprocedure specified in clause 5.10.3.If none of the default EPS bearers have been accepted by the target eNodeB or there is a LIPA PDN connection that has not been released, the MME shall act as specified in step 6.3. If the Serving GW has received the User Location Information IE and/or the UE Time Zone IEand/or the Serving Network IE and/or User CSG Information IE from the MME in step 2 theServing GW informs the PDN GW(s) about this information that e.g. can be used for charging, by sending the message Modify Bearer Request (Serving GW Address and TEID, User LocationInformation IE and/or UE Time Zone IE and/or Serving Network IE and/or User CSG Information IE) per PDN connection to the PDN GW(s) concerned. The Serving GW shall return a Modify Bearer Response (Serving GW address and TEID for uplink traffic) message to the MME as a response to a Modify Bearer Request message, or a Modify Access Bearers Response (Serving GW address and TEID for uplink traffic) as a response to a Modify Access Bearers Request message. If the Serving GW cannot serve the MME Request in the Modify Access Bearers Request message without S5/S8 signalling or without corresponding Gxc signalling when PMIP is used over the S5/S8 interface, it shall respond to the MME with indicating that the modifications are not limited to S1-U bearers, and the MME shall repeat its request using Modify Bearer Request message per PDN connection.4. The Serving GW starts sending downlink packets to the target eNodeB using the newly receivedaddress and TEIDs. A Modify Bearer Response message is sent back to the MME.5. In order to assist the reordering function in the target eNodeB, the Serving GW shall send one ormore "end marker" packets on the old path immediately after switching the path as defined inTS 36.300 [5], clause 10.1.2.2.6. The MME confirms the Path Switch Request message with the Path Switch Request Ack message.If the UE-AMBR is changed, e.g. all the EPS bearers which are associated to the same APN are rejected in the target eNodeB, the MME shall provide the updated value of UE-AMBR to the target eNodeB in the Path Switch Request Ack message.If some EPS bearers have not been switched successfully in the core network, the MME shallindicate in the Path Switch Request Ack message which bearers failed to be established (see more detail in TS 36.413 [36]) and for dedicated bearers initiate the bearer release procedure as specified in clause 5.4.4.2 to release the core network resources of the failed dedicated EPS bearers. Thetarget eNodeB shall delete the corresponding bearer contexts when it is informed that bearers have not been established in the core network.If none of the default EPS bearers have been switched successfully in the core network or if they have not been accepted by the target eNodeB or the LIPA PDN connection has not been released, the MME shall send a Path Switch Request Failure message (see more detail in TS 36.413 [36]) to the target eNodeB. The MME performs explicit detach of the UE as described in the MME initiated detach procedure of clause 5.3.8.3.7. By sending Release Resource the target eNodeB informs success of the handover to source eNodeBand triggers the release of resources. This step is specified in TS 36.300 [5].8. The UE initiates a Tracking Area Update procedure when one of the conditions listed in clause"Triggers for tracking area update" applies. If ISR is activated for the UE when the MME receives the Tracking Area Update Request, the MME should maintain ISR by indicating ISR Activated in the Tracking Area Update Accept message.NOTE 3: It is only a subset of the TA update procedure that is performed by the MME, since the UE is in ECM-CONNECTED state and the MME is not changed.1.1.3 X2-based handover with Serving GW relocationThis procedure is used to hand over a UE from a source eNodeB to a target eNodeB using X2 when the MME is unchanged and the MME decides that the Serving GW is to be relocated. The presence of IP connectivity between the source Serving GW and the source eNodeB, between the source Serving GW and the target eNodeB, and between the target Serving GW and target eNodeB is assumed. (If there is no IP connectivity between target eNodeB and source Serving GW, it is assumed that the S1-based handover procedure in clause 1.2 shall be used instead.)Figure 1.1.3-1: X2-based handover with Serving GW relocationNOTE 1: For a PMIP-based S5/S8, procedure steps (A) and (B) are defined in TS 23.402 [2].1. The target eNodeB sends a Path Switch Request message to MME to inform that the UE haschanged cell, including the ECGI of the target cell and the list of EPS bearers to be switched. If the target cell is a CSG cell , the target eNodeB includes the CSG ID of the target cell in Path Switch Request message. If the target cell is in hybrid mode, it includes the CSG ID of the target cell and CSG Access Mode set to "hybrid" in the Path Switch Request message. The MME determines the CSG membership based on the CSG ID and CSG Access Mode received from the targeteNodeB.The MME updates the User CSG information based on the CSG ID and CSG Access Mode received from the target eNodeB and CSG membership if one of the parameters has changed.NOTE 2: X2 handover between HeNBs is possible when the handover is between closed/hybrid access HeNBs having the same CSG ID or when the target HeNB is an open access HeNB.The MME determines that the Serving GW is relocated and selects a new Serving GW according to clause 4.3.8.2 on "Serving GW Selection Function".NOTE 3: The MME knows the S-GW Service Area with a TA granularity.2. The MME sends a Create Session Request (bearer context(s) with PDN GW addresses and TEIDs(for GTP-based S5/S8) or GRE keys (for PMIP-based S5/S8) at the PDN GW(s) for uplink traffic, eNodeB address(es) and TEIDs for downlink user plane for the accepted EPS bearers, the Protocol Type over S5/S8, Serving Network, UE Time Zone) message per PDN connection to the target Serving GW for each PDN connection where the default bearer has been accepted by the target eNodeB. The target Serving GW allocates the S-GW addresses and TEIDs for the uplink traffic on S1_U reference point (one TEID per bearer). The Protocol Type over S5/S8 is provided to Serving GW which protocol should be used over S5/S8 interface. If the PDN GW requested UE's location info, the MME also includes the User Location Information IE in this message. If the PDN GW requested UE's User CSG information (determined from the UE context), the MME includes the User CSG Information IE in this message if the User CSG Information has changed.The MME uses the list of EPS bearers to be switched, received in step 1, to determine whether any dedicated EPS bearers in the UE context have not been accepted by the target eNodeB. The MME releases the non-accepted dedicated bearers by triggering the bearer release procedure as specified in clause 5.4.4.2 via target Serving GW. If the Serving GW receives a DL packet for a non-accepted bearer, the Serving GW drops the DL packet and does not send a Downlink Data Notification to the MME.If the default bearer of a PDN connection has not been accepted by the target eNodeB and there are multiple PDN connections active, the MME shall consider all bearers of that PDN connection as failed and release that PDN connection by triggering the MME requested PDN disconnectionprocedure specified in clause 5.10.3 via source Serving GW.If none of the default EPS bearers have been accepted by the target eNodeB or there is a LIPA PDN connection that has not been released, the MME shall act as specified in step 5.3. The target Serving GW assigns addresses and TEIDs (one per bearer) for downlink traffic from thePDN GW. The Serving GW allocates DL TEIDs on S5/S8 even for non-accepted bearers. It sends a Modify Bearer Request (Serving GW addresses for user plane and TEID(s), Serving Network) message per PDN connection to the PDN GW(s). The S-GW also includes User LocationInformation IE and/or UE Time Zone IE and/or User CSG Information IE if it is present in step 2.The PDN GW updates its context field and returns a Modify Bearer Response (Charging Id,MSISDN, etc.) message to the Serving GW. The MSISDN is included if the PDN GW has it stored in its UE context. The PDN GW starts sending downlink packets to the target GW using the newly received address and TEIDs. These downlink packets will use the new downlink path via the target Serving GW to the target eNodeB. The Serving GW shall allocate TEIDs for the failed bearers and inform to the MME.4. The target Serving GW sends a Create Session Response (Serving GW addresses and uplinkTEID(s) for user plane) message back to the target MME. The MME starts a timer, to be used in step 7.5. The MME confirms the Path Switch Request message with the Path Switch Request Ack (ServingGW addresses and uplink TEID(s) for user plane) message. If the UE-AMBR is changed, e.g. all the EPS bearers which are associated to the same APN are rejected in the target eNodeB, the MME shall provide the updated value of UE-AMBR to the target eNodeB in the Path Switch Request Ack message. The target eNodeB starts using the new Serving GW address(es) and TEID(s) forforwarding subsequent uplink packets.If some EPS bearers have not been switched successfully in the core network, the MME shallindicate in the Path Switch Request Ack message which bearers failed to be established (see more detail in TS 36.413 [36]) and for dedicated bearers initiate the bearer release procedure as specified in clause 5.4.4.2 to release the core network resources of the failed dedicated EPS bearers. The target eNodeB shall delete the corresponding bearer contexts when it is informed that bearers have not been established in the core network.If none of the default EPS bearers have been switched successfully in the core network or if theyhave not been accepted by the target eNodeB or the LIPA PDN connection has not been released, the MME shall send a Path Switch Request Failure message (see more detail in TS 36.413 [36]) to the target eNodeB. The MME performs explicit detach of the UE as described in the MME initiated detach procedure of clause 5.3.8.3.6. By sending Release Resource the target eNodeB informs success of the handover to source eNodeBand triggers the release of resources. This step is specified in TS 36.300 [5].7. When the timer has expired after step 4, the source MME releases the bearer(s) in the sourceServing GW by sending a Delete Session Request message (Cause, Operation Indication). Theoperation Indication flag is not set, that indicates to the Source Serving GW that the Source Serving GW shall not initiate a delete procedure towards the PDN GW. The Source Serving GWacknowledges with Delete Session Response messages. If ISR has been activated before thisprocedure, the cause indicates to the Source S-GW that the Source S-GW shall delete the bearerresources on the other old CN node by sending Delete Bearer Request message(s) to that CN node.8. The UE initiates a Tracking Area Update procedure when one of the conditions listed in clause"Triggers for tracking area update" applies.NOTE 4: It is only a subset of the TA update procedure that is performed by the MME, since the UE is in ECM-CONNECTED state. The UE is informed about the ISR status in the Tracking AreaUpdate procedure.1.2 S1-based handover1.2.1 GeneralThe S1-based handover procedure is used when the X2-based handover cannot be used. The source eNodeB initiates a handover by sending Handover Required message over the S1-MME reference point. This procedure may relocate the MME and/or the Serving GW. The source MME selects the target MME. The MME should not be relocated during inter-eNodeB handover unless the UE leaves the MME Pool Area where the UE is served. The MME (target MME for MME relocation) determines if the Serving GW needs to be relocated. If the Serving GW needs to be relocated the MME selects the target Serving GW, as specified in clause 4.3.8.2 on Serving GW selection function.The source eNodeB decides which of the EPS bearers are subject for forwarding of downlink and optionally also uplink data packets from the source eNodeB to the target eNodeB. The EPC does not change the decisions taken by the RAN node. Packet forwarding can take place either directly from the source eNodeB to the target eNodeB, or indirectly from the source eNodeB to the target eNodeB via the source and target Serving GWs (or if the Serving GW is not relocated, only the single Serving GW).The availability of a direct forwarding path is determined in the source eNodeB and indicated to the source MME. If X2 connectivity is available between the source and target eNodeBs, a direct forwarding path is available.If a direct forwarding path is not available, indirect forwarding may be used. The source MME uses the indication from the source eNodeB to determine whether to apply indirect forwarding. The source MME indicates to the target MME whether indirect forwarding should apply. Based on this indication, the target MME determines whether it applies indirect forwarding.If the MME receives a rejection to an S1 interface procedure (e.g. dedicated bearerestablishment/modification/release; location reporting control; NAS message transfer; etc.) from the eNodeB with an indication that an S1 handover is in progress (see TS 36.300 [5]), the MME shall reattempt the same S1 interface procedure when either the handover is complete or is deemed to have failed if the MME is still the serving MME, except in case of Serving GW relocation.In order to minimise the number of procedures rejected by the eNodeB, the MME should pause non-handover related S1 interface procedures (e.g. downlink NAS message transfer, E-RABSetup/Modify/Release, etc.) while a handover is ongoing (i.e. from the time that a Handover Required has been received until either the Handover procedure has succeeded (Handover Notify) or failed (Handover Failure)) and continue them once the Handover procedure has completed if the MME is still the serving MME, except in case of Serving GW relocation.If during the handover procedure the MME detects that the Serving GW or/and the MME needs be relocated, the MME shall reject any PDN GW initiated EPS bearer(s) request received since handover procedure started and shall include an indication that the request has been temporarily rejected due to handover procedure in progress. The rejection is forwarded by the Serving GW to the PDN GW, with the same indication.Upon reception of a rejection for an EPS bearer(s) PDN GW initiated procedure with an indication that the request has been temporarily rejected due to handover procedure in progress, the PDN GW start a locally configured guard timer. The PDN GW shall re-attempt, up to a pre-configured number of times, when either it detects that the handover is completed or has failed using message reception or at expiry of the guard timer.If emergency bearer services are ongoing for the UE, handover to the target eNodeB is performed independent of the Handover Restriction List. The MME checks, as part of the Tracking Area Update in the execution phase, if the handover is to a restricted area and if so MME releases the non-emergency bearers as specified in clause 5.10.3.If the MME receives a rejection to a UE Context modification Request message with a CS Fallback indication from the eNodeB with an indication that an S1 handover is in progress, the MME shall resend a UE Context Modification Request message with CS Fallback indicator to the target eNodeB when either the handover is complete or to the source eNodeB when the handover is deemed to have failed if the MME is still the serving MME.For inter-PLMN handover to a CSG cell, based on operator's configuration the source MME may allow the handover by validating the CSG membership of the UE in the target CSG cell using the CSG-ID list of the registered PLMN-ID. Otherwise, the source MME shall reject the handover due to no CSG membership information of the target PLMN-ID.1.2.2 S1-based handover, normalThis procedure describes the S1-based handover in the normal case, clause 1.2.3 describes it when the procedure is rejected by the target eNodeB or the target MME and clause 1.2.4 describes when the procedure is canceled by the source eNodeB.Figure 1.2.2-1: S1-based handoverNOTE 1: For a PMIP-based S5/S8, procedure steps (A) and (B) are defined in TS 23.402 [2]. Steps 16 and 16a concern GTP based S5/S8.NOTE 2: If the Serving GW is not relocated, the box "Source Serving GW" in figure 1.2.2-1 is acting as the target Serving GW.1. The source eNodeB decides to initiate an S1-based handover to the target eNodeB. This can betriggered e.g. by no X2 connectivity to the target eNodeB, or by an error indication from the target eNodeB after an unsuccessful X2-based handover, or by dynamic information learnt by the source eNodeB.2. The source eNodeB sends Handover Required (Direct Forwarding Path Availability, Source toTarget transparent container, target eNodeB Identity, CSG ID, CSG access mode, target TAI, S1AP Cause) to the source MME. The source eNodeB indicates which bearers are subject to dataforwarding. Direct Forwarding Path Availability indicates whether direct forwarding is available from the source eNodeB to the target eNodeB. This indication from source eNodeB can be based one.g. the presence of X2. The target TAI is sent to MME to facilitate the selection of a suitable targetMME. When the target cell is a CSG cell or a hybrid cell, the source eNodeB shall include the CSG ID of the target cell. If the target cell is a hybrid cell, the CSG access mode shall be indicated.3. The source MME selects the target MME as described in clause4.3.8.3 on "MME SelectionFunction" and if it has determined to relocate the MME, it sends a Forward Relocation Request (MME UE context, Source to Target transparent container, RAN Cause, target eNodeB Identity, CSG ID, CSG Membership Indication, target TAI, MS Info Change Reporting Action (if available), CSG Information Reporting Action (if available), UE Time Zone, Direct Forwarding Flag, Serving Network) message to the target MME. The target TAI is sent to the target MME to help it todetermine whether S-GW relocation is needed (and, if needed, aid SGW selection). The old Serving Network is sent to target MME to support the target MME to resolve if Serving Network is changed.In network sharing scenarios Serving Network denotes the serving core network.The source MME shall perform access control by checking the UE's CSG subscription when CSG ID is provided by the source eNodeB. If there is no subscription data for this CSG ID or the CSG subscription is expired, and the target cell is a CSG cell, the source MME shall reject the handover with an appropriate cause.The MME UE context includes IMSI, ME Identity, UE security context, UE Network Capability, AMBR, Selected CN operator ID, APN restriction, Serving GW address and TEID for controlsignalling, and EPS Bearer context(s).An EPS Bearer context includes the PDN GW addresses and TEIDs (for GTP-based S5/S8) or GRE keys (for PMIP-based S5/S8) at the PDN GW(s) for uplink traffic, APN, Serving GW addresses and TEIDs for uplink traffic, and TI.RAN Cause indicates the S1AP Cause as received from source eNodeB.The source MME includes the CSG ID in the Forward Relocation Request when the target cell is a CSG or hybrid cell. When the target cell is a hybrid cell, the CSG Membership Indication indicating whether the UE is a CSG member shall be included in the Forward Relocation Request message.The Direct Forwarding Flag indicates if direct forwarding is applied, or if indirect forwarding is going to be set up by the source side.The target MME shall determine the Maximum APN restriction based on the APN Restriction of each bearer context in the Forward Relocation Request, and shall subsequently store the newMaximum APN restriction value.If the UE receives only emergency services and the UE is UICCless, IMSI can not be included in the MME UE context in Forward Relocation Request message. For emergency attached UEs, if the IMSI cannot be authenticated, then the IMSI shall be marked as unauthenticated. Also, in this case, security parameters are included only if available.4. If the MME has been relocated, the target MME verifies whether the source Serving GW cancontinue to serve the UE. If not, it selects a new Serving GW as described in clause 4.3.8.2 on "Serving GW Selection Function". If the MME has not been relocated, the source MME decides on this Serving GW re-selection.If the source Serving GW continues to serve the UE, no message is sent in this step. In this case, the target Serving GW is identical to the source Serving GW.If a new Serving GW is selected, the target MME sends a Create Session Request (bearer context(s) with PDN GW addresses and TEIDs (for GTP-based S5/S8) or GRE keys (for PMIP-based S5/S8) at the PDN GW(s) for uplink traffic, Serving Network, UE Time Zone) message per PDNconnection to the target Serving GW. The target Serving GW allocates the S-GW addresses and TEIDs for the uplink traffic on S1_U reference point (one TEID per bearer). The target Serving GW sends a Create Session Response (Serving GW addresses and uplink TEID(s) for user plane)message back to the target MME.5. The Target MME sends Handover Request (EPS Bearers to Setup, AMBR, S1AP Cause, Source toTarget transparent container, CSG ID, CSG Membership Indication, Handover Restriction List) message to the target eNodeB. This message creates the UE context in the target eNodeB, including information about the bearers, and the security context. For each EPS Bearer, the Bearers to Setup includes Serving GW address and uplink TEID for user plane, and EPS Bearer QoS. If the direct forwarding flag indicates unavailability of direct forwarding and the target MME knows that there is no indirect data forwarding connectivity between source and target, the Bearers to Setup shallinclude "Data forwarding not possible" indication for each EPS bearer. Handover Restriction List is sent if available in the Target MME; it is described in clause 4.3.5.7 "Mobility Restrictions".S1AP Cause indicates the RAN Cause as received from source MME.The Target MME shall include the CSG ID and CSG Membership Indication when provided by the source MME in the Forward Relocation Request message.The target eNodeB sends a Handover Request Acknowledge (EPS Bearer Setup list, EPS Bearers failed to setup list Target to Source transparent container) message to the target MME. The EPS Bearer Setup list includes a list of addresses and TEIDs allocated at the target eNodeB for downlink traffic on S1-U reference point (one TEID per bearer) and addresses and TEIDs for receivingforwarded data if necessary. If the UE-AMBR is changed, e.g. all the EPS bearers which areassociated to the same APN are rejected in the target eNodeB, the MME shall recalculate the new UE-AMBR and signal the modified UE-AMBR value to the target eNodeB.If none of the default EPS bearers have been accepted by the target eNodeB, the target MME shall reject the handover as specified in clause 1.2.3.If the target cell is a CSG cell, the target eNodeB shall verify the CSG ID provided by the target MME, and reject the handover with an appropriate cause if it does not match the CSG ID for the target cell. If the target eNodeB is in hybrid mode, it may use the CSG Membership Indication to perform differentiated treatment for CSG and non-CSG members.6. If indirect forwarding applies and the Serving GW is relocated, the target MME sets up forwardingparameters by sending Create Indirect Data Forwarding Tunnel Request (target eNodeB addresses。
lte异频切换信令流程
lte异频切换信令流程LTE（Long Term Evolution）是一种4G无线通信技术，为了提供更高的数据传输速率和更好的用户体验，LTE网络支持异频切换（Inter-frequency Handover）功能。
异频切换是指当用户从一个频率（或信道）切换到另一个频率（或信道）时，保持通信的连续性和稳定性。
本文将详细介绍LTE异频切换的信令流程。
1. 切换触发LTE异频切换的触发可以由多种因素引起，例如当前信道质量较差、用户移动速度较快或者网络负载过高等。
当这些条件满足时，基站会发出切换请求给用户设备。
切换请求可以通过系统信息广播或者单播的方式传输给用户设备。
2. 测量报告一旦用户设备接收到切换请求，它会开始测量附近的其他频率。
用户设备会周期性地向当前连接的基站发送测量报告，包括附近频率的信号强度、信号质量等参数。
基站根据这些测量报告来评估其他频率的可用性和适用性。
3. 切换决策基站收集到用户设备的测量报告后，会根据预设的切换策略和算法进行切换决策。
切换决策主要考虑目标频率的信号强度、信号质量以及网络负载情况等因素。
基站会选择最适合的目标频率，并发送切换请求给用户设备。
4. 切换请求基站向用户设备发送切换请求，请求其切换到目标频率。
切换请求中包含目标频率的相关信息，以及切换所需的参数和配置。
用户设备接收到切换请求后，会进行相应的切换准备工作。
5. 邻区搜索用户设备在接收到切换请求后，会执行邻区搜索过程，以获取目标频率的邻区信息。
邻区搜索是为了获取目标频率的信号强度和质量，以便用户设备做出更准确的切换决策。
6. 切换准备用户设备根据目标频率的邻区信息和切换请求中的参数进行切换准备。
这包括调整接收机的频率和配置，准备好切换所需的资源和参数。
用户设备必须确保在切换过程中不会中断正在进行的通信。
7. 切换执行一旦用户设备完成切换准备，它会发送切换执行命令给基站，请求切换到目标频率。
基站接收到切换执行命令后，会执行相应的切换操作，包括释放当前频率的资源、分配目标频率的资源等。
LTE系统信令流程八
6. PS Handover Complete 7. XID Response 8. Forward Relocation Complete Notification 8a. Forward Relocation Complete Acknowledge 9. Modify Bearer Request For Serving GW relocation Steps 9, 10 and 11, and the following User Plane path, will be handled by Target Serving GW 12. XID Negotiation for LLC ADM 12a. SABM UA exchange re-establishment and XID negotiation for LLC ABM) Uplink and Downlink User Plane PDUs 13. Routeing Area Update procedure 13a. PS Handover Complete Ack 14. Delete Session Request 14b. Release Resource (B) 14a. Delete Session Response 15. Delete Indirect Data Forwarding Tunnel Request 15a. Delete Indirect Data Forwarding Tunnel Response 16. Delete Indirect Data Forwarding Tunnel Request 16a. Delete Indirect Data Forwarding Tunnel Response 10. Modify Bearer Request (A) 10a. Modify Bearer Response 11. Modify Bearer Response
切换失败事件层三信令详解
切换失败原因手机在通话中为了保证通话质量，经常会切换到能够提供更好服务的小区上去，如果移动的距离较长，则会发生多次切换的现象。
虽然切换失败不等同于掉话，但在GSM网络中切换失败就意味着增加了网络的信令流量，并且也是掉话的隐患。
因此处理好切换关系，减少切换失败的任务是优化工作非常重要的一项环节。
在这一章里我们将从路测角度结合实例来分析日常工作中会遇到的切换失败的现象，并分析造成各种现象的原因以及相应的处理办法。
总的来说，在遇到切换失败事件时首先应该从HO_FAILURE消息中查找切换失败的原因解释（Causevalue）,有些切换失败是可以直接查到切换失败原因的（可以详查GSM规范）。
但对于有些Cause value，如Cause value111（Protocol error，unspecified）、Cause value 3（Abnormal release，timer expired）等就无法定位具体原因。
对于这些情况，我们就应该再进一步的对信令流程、多种测量参数、统计报告以及测试现场的环境等进行综合的分析，从而进一步确定切换失败原因。
下面的大部分篇幅的分析解决办法都是基于这些无法定位具体原因的Cause value。
一、连续的切换失败测试中我们有时会遇到这样的情况：如图7所示，接连不断的出现切换失败，当测试工程师继续驱车向前行驶时，就可能导致拖带掉话。
从系统下行发送的Handover_Command消息中我们可以发现，目标小区都是同一个小区（或同一个基站的不同小区）。
此种现象一般都和基站或传输设备的时钟故障有关，但也有可能是同频同BISC的小区造成的。
二、单独出现的切换失败如上所述，面对连续的切换失败时，我们的目标比较明确，而且基本上都是与时钟等硬件有关，比较容易发现问题，也比较好解决。
而实际工作中，却存在着偶尔单独出现的切换失败现象。
出现这种现象的原因却是多种多样，我们在这一节中将针对不同的现象分析不同的原因，值得注意的是，虽然大多数单独出现的切换失败现象很相似，但通过对信令的分析（时间、帧号、信令内容等），就会找出切换失败的具体原因。
LTE信令流程详解
LTE信令流程详解LTE（Long Term Evolution）是一种无线通信技术，它的信令流程是指移动设备和基站之间进行通信时所涉及的过程和协议。
下面将详细介绍LTE信令流程。
1.邻小区：当移动设备打开或重新启动时，它首先会周围的基站和小区信息。
移动设备通过读取广播消息、相邻小区信息和测量报告等来获取附近基站的信息。
2.小区选择和附着：移动设备选择一个适合自己的基站，并向其发送附着请求消息。
附着请求消息中包含设备的身份信息和位置等信息。
基站会对附着请求消息进行验证，并根据验证结果决定是否允许移动设备接入LTE网络。
3.鉴权：当设备成功附着到基站后，基站会发送鉴权请求消息给移动设备。
移动设备会将自己的鉴权信息发送给基站进行验证。
如果鉴权成功，移动设备就可以进入下一步。
4.配置：在鉴权成功后，基站和移动设备会进行一系列的配置，包括分配临时标识、分配IP地址、设置协议参数等。
这些配置过程的目的是为了确保设备和网络之间的正常通信。
5.建立承载：在配置完成后，移动设备会发送一个承载请求给基站，请求建立数据传输承载。
基站会根据网络负载情况和设备的需求来决定是否建立承载。
如果建立成功，移动设备就可以进行数据传输了。
6.数据传输：一旦数据传输承载建立成功，移动设备就可以通过LTE网络进行数据传输了。
数据可以通过IP传输协议进行传输，也可以通过其他协议进行传输，比如VoIP、视频流等。
7.承载释放：当数据传输结束或不再需要传输时，移动设备会发送一个承载释放请求给基站，请求释放数据传输承载。
基站会根据设备的请求来决定是否释放承载。
8. Switch Handover（切换切换）：当移动设备处于移动状态时，为了保持持续的通信，可能需要切换到其他基站的覆盖范围内。
移动设备会发送一个切换请求给目标基站，目标基站会与源基站进行协调，并进行切换。
9.释放附着：当移动设备需要离开网络或者切换到其他网络时，会发送一个释放附着请求给当前附着的基站，请求释放附着。
GSM信令完整流程
UL: AUTHENTICATION RESPONSE 鉴权响应
DL: CIPHER MODE COMMAND
UL: CIPHER MODE COMPLETE
DL: TMSI REALLOCATION COMMAND TMSI分配命令
UL: TMSI REALLOCATION COMPLETE TMSI分配完成
呼叫失败
Paging Request Channel Request Immediate Assignment CM Service Request System Information Type1（在一次呼叫过程中，若连续出现多个CM Service Request，则视为一次呼叫失败）
正常的呼叫流程
呼叫成功
2023最新整理收集 do something
Paging Request Channel Requet 信道请求 Immediate Assignment 立即指配 CM Service Request (CM连接管理层) CM Service Accept CM业务接收 Setup 建立 Call Proceeding 呼叫进程 Assignment Command 指配命令 Assignment Complete 指配完成 Connect/Alerting 响铃
感感
谢 阅
谢
读阅
读
Classmark Enquiry Identity Request Classmark Change Classmark Change Identity Response Tmsi Reallocation Command Tmsi Reallocation Complete Cm Service Accept Setup Call Proceeding Assignment Command Assignment Complete Alerting Connect Connect Acknowledge Disconnect Release Release Complete Channel Release
常见异常事件信令分析
常见异常事件信令分析目录：一、日常指标中常见异常事件 (2)1、SDCCH拥塞： (2)2、SDCCH分配失败： (3)2.1无线原因引起SDCCH分配失败： (3)2.2 BSS问题引起的SDCCH分配失败： (3)2.3 SDCCH分配失败信令分析： (3)3、SDCCH掉话 (7)3.1无线问题引起SDCCH掉话： (7)3.2 BSS问题引起SDCCH掉话： (7)3.3 SDCCH掉话信令分析 (8)4、TCH拥塞 (10)5、TCH分配失败 (11)5.1无线原因引起的TCH分配失败： (11)5.2 BSS原因引起的TCH分配失败： (12)5.3 TCH分配失败信令分析： (13)6、TCH掉话 (16)6.1无线问题引起TCH掉话： (16)6.2切换失败引起TCH掉话： (17)6.3 BSS内部原因引起TCH掉话： (17)6.4传输问题引起TCH掉话： (17)6.5 TCH掉话信令分析： (18)6.5.1 MC736掉话 (18)6.5.2 MC621掉话 (19)6.5.3 MC14C掉话 (21)6.5.4 MC739掉话 (21)6.5.5 正常的挂机 (22)7、切换异常事件 (26)7.1、无线原因引起的切换失败返回信令流程（小区间异步切换）： (26)7.2、系统原因（BSS问题）引起的切换失败 (26)7.3、切换失败信令分析： (26)二、DT测试中的异常事件 (30)1、未接通 (30)1.1由于TCH拥塞 (30)1.2位置更新引起 (33)2、paging失败 (35)3、TCH掉话 (35)三、附录 (38)Abis口信令名词缩写解释： (38)一、日常指标中常见异常事件日常指标中常见异常事件主要表现为：SDCCH拥塞、SDCCH分配失败、SDCCH 掉话、TCH拥塞、TCH分配失败、TCH掉话、TCH切换失败1、SDCCH拥塞：信令流程如下：MC02a 位置更新次数MC02h 所有主叫电话占用SDCCH次数MC04 SDCCH拥塞次数当用户发起CHANNEL REQUEST时，网络发现无空闲的SDCCH信道时，BSC将会：如果小区参数En_Imm_Ass_Rej=“True”，则发Immediately Assignment Reject；否则Channel Required消息。
ZTE-LTE信令跟踪方法及案例分析
1.5 LTE无线网管信令跟踪---跟踪标识解析
eNodeB MME码 标识 586759 586759 586759 1 1 1 GID 17342 16641 16890 M-TMSI 3339033373 3288450704 3390024549 MME-UE-S1AP 标识 6296776 6296296 6294872
12
1.6 LTE无线网管信令跟踪---典型信令(measurementReport)
measurementReport_r8 tOptFlags nonCriticalExtensionPresent = 0 measResults tOptFlags measResultNeighCellsPresent = 1 verExt2Present = 0 verExt3Present = 0 measId = 3 服务小区 measResultPCell 测量结果 rsrpResult = 49 rsrqResult = 11 measResultNeighCells t=1 u measResultListEUTRA n=2 elem[0] 邻区小区 tOptFlags 测量结果 cgi_InfoPresent = 0 physCellId = 120 measResult tOptFlags rsrpResultPresent = 1 rsrqResultPresent = 0 verExt2Present = 0 rsrpResult = 49 elem[1] tOptFlags cgi_InfoPresent = 0 physCellId = 127 measResult tOptFlags rsrpResultPresent = 1 rsrqResultPresent = 0 verExt2Present = 0 rsrpResult = 48
LTE切换流程和信令介绍
LTE切换流程和信令介绍LTE（Long Term Evolution）是第四代移动通信技术，它提供了更高的数据传输速率和更低的时延，以满足日益增长的移动通信需求。
在LTE网络中，设备可以通过切换来在不同基站之间进行无缝连接。
LTE切换流程和信令起着至关重要的作用，下面将详细介绍。
首先是触发切换阶段。
当用户设备处于LTE网络中，并且当前基站的信号质量或容量不足以满足设备的需求时，切换过程就会被触发。
通常，切换触发有两种方式：主动切换和被动切换。
- 主动切换由用户设备发起，例如手动选择区域（PLMN）或小区（cell）。
-被动切换由网络管理者发起，例如基站或网络控制器（MME）。
接下来是执行切换阶段。
一旦切换被触发，设备将与新的基站建立连接，同时还要进行测量和评估新旧基站之间的信号质量差异。
执行切换的关键过程包括：-选取目标小区：根据测量结果和策略，设备选择目标小区进行连接。
-建立目标小区连接：设备向目标小区发送连接请求，并与之建立连接。
-配置和激活服务：设备和目标小区之间进行协商，配置和激活所需的服务属性。
-传输数据重新分配：在完成连接建立之后，设备和目标小区之间协商数据传输重新分配，以确保数据在新小区上的传输。
最后是完成切换阶段。
在完成切换后，设备将与之前的基站断开连接，并与目标基站实现无缝切换，以确保通信的连续性。
完成切换的关键过程包括：-基站释放：设备向原始基站发送释放连接请求，并与之断开连接。
-确认连接建立：设备向目标基站发送连接确认，以确认连接建立并准备开始数据传输。
-数据传输切换：在完成连接确认后，设备和目标基站之间进行数据传输切换，以确保数据正常传输。
在LTE切换过程中- 切换请求（Handover Request）：设备发送给LTE网络的信令，用于请求执行切换。
- 小区测量报告（Cell Measurement Report）：设备发送给网络的报告，包含对周围基站信号质量的测量结果。
不同msc之间的移动通信的信令流程
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文档下载后可定制随意修改，请根据实际需要进行相应的调整和使用，谢谢!并且，本店铺为大家提供各种各样类型的实用资料，如教育随笔、日记赏析、句子摘抄、古诗大全、经典美文、话题作文、工作总结、词语解析、文案摘录、其他资料等等，如想了解不同资料格式和写法，敬请关注!Download tips: This document is carefully compiled by theeditor.I hope that after you download them,they can help yousolve practical problems. The document can be customized andmodified after downloading,please adjust and use it according toactual needs, thank you!In addition, our shop provides you with various types ofpractical materials,such as educational essays, diaryappreciation,sentence excerpts,ancient poems,classic articles,topic composition,work summary,word parsing,copy excerpts,other materials and so on,want to know different data formats andwriting methods,please pay attention!理解不同MSC之间的移动通信信令流程移动通信系统是一个复杂而精密的网络，其中Mobile Switching Center（MSC）是核心组成部分，负责处理语音和数据呼叫、控制移动台的切换以及管理移动用户的位置信息。
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Intra BSC Inter Cell Handover (RMHOEC) • New channel(s) in other cell in same BSC requested
Inter BSC and Inter System Handover (RMHOEB) • New channel(s) in other cell in other BSC requested
英才直通车 7
Module Name
Handover Triggers
MSC BSC CPR
RMCHO RMCC RMHBI
BTS
• Half Rate Packing • Subcell Load Distribution
BG-CH
RMCC initiates RMCHO if a Handover is allowed to be started. Control of Handover (RMCHO) initiates: Intra BSC Intra Cell Handover (RMHOAC) Note: No candidate list is needed since a handover shall be performed within same cell or subcell.
RMCC initiates RMCHO if a Handover is allowed to be started.
Control of Handover (RMCHO) requests for a candidate list.
RCQS
Control of Handover (RMCHO) decides which procedure to initiate. Input for the decision is the received cell candidate list (max 7 candidates).
BG-CH
RTS
Note: Not done for signalling connections
RTS
CHANNEL ACTIVATION RMHOAC orders RMHTR to activate the channel(s). RMHTR orders RMHBI to activate the channel(s). CHANNEL ACTIVATION ACKNOWLEDGE
英才直通车
2
Module Name
HANDOVER Purpose: •Maintain a good radio transmission quality for a connection
•Control and direct a connection such that the overall radio service in the network is optimized
BG-CH
MSC
RTS
• 08.08 Handover Request (incomming call from GSM or UMTS)
英才直通车andover Triggers
MSC BSC BTS
CPR
Cell Candidate List
RMCC RMCHO RMHBI
Note: No candidate list is needed since the target cell is received from the MSC.
英才直通车
9
Module Name
Handover Procedures
Intra BSC Intra Cell Handover (RMHOAC) • New channel(s) in same subcell requested
英才直通车 11
Module Name
Intra BSC Intra Cell Handover (RMHOAC)
英才直通车
12
Module Name
Handover Procedures
Intra BSC Intra Cell Handover (RMHOAC)
MSC BSC CPR
RMCHO RMHOAC RMHTR RMHBI
Connection established between MS and BTS
Note: Not done for signalling connections
ASSIGNMENT COMMAND ESTABLISH INDICATION
One of the following procedures is initiated: - Intra BSC Intra Cell Handover (RMHOAC) - Intra BSC Inter Cell Handover (RMHOEC) - Inter BSC and Inter System Handover (RMHOEB) RMCC informs RMPH about the handover result.
英才直通车
5
Module Name
Handover Triggers
MSC BSC BTS
Channels blocked due to operation and BG-CH maintenance
CPR
RMCHO RMCC RMHBI
RMCC initiates RMCHO if a Handover is allowed to be started. Control of Handover (RMCHO) requests for a candidate list. Control of Handover (RMCHO) decides which procedure to initiate. Input for the decision is the received cell candidate list (max 7 candidates). One of the following procedures is initiated: - Intra BSC Intra Cell Handover (RMHOAC) - Intra BSC Inter Cell Handover (RMHOEC) - Inter BSC and Inter System Handover (RMHOEB)
BTS
- Channel Type - Target Cell [- Priority] [- CIC] [-Downlink DTX]
RMHAIDL checks the message. RMCC initiates RMCHO.
Control of Handover (RMCHO) initiates: Inter BSC and Inter System Handover (RMHOEB)
RCQS
RMCHO checks with RMCC if a Handover is allowed to be started. Control of Handover (RMCHO) decides which procedure to initiate. Input for the decision is the received cell candidate list (max 7 candidates). One of the following procedures is initiated: - Intra BSC Intra Cell Handover (RMHOAC) - Intra BSC Inter Cell Handover (RMHOEC) - Inter BSC and Inter System Handover (RMHOEB)
Chapter 6 Handover
英才直通车
1
Module name
Chapter 6 OBJECTIVES
Upon completion of this chapter the student will be able to: • • • • Understand the handover Algorithm Describe the signalling procedure for handover Describe the relevant function blocks and their function Describe internal signals for handover
Handover result
RMCC informs BG-CH via RMHBI about the handover result.
BG-CH
英才直通车
8
Module Name
Handover Triggers
MSC BSC CPR HANDOVER REQUEST
RMHAIDL RMCC RMCHO
Handover
Procedure blocks
RMHOAC
RMCHO
RMHOEC
RMHTR
RMHOEB Seizes/Releases: - Channel - TRA - Set up of paths between A-mup and TRA - Set up of paths between TRA and abis-mup
英才直通车
13
Module Name
Handover Procedures
Intra BSC Intra Cell Handover (RMHOAC)
MSC BSC CPR
RMCHO RMHOAC RMHBI
BTS
RMHOAC orders the MS via RMHBI to change to the new channel.