LTE典型信令过程课件.ppt

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1、LTE 典型信令过程,LTE 典型信令过程,Software Architecture,Software Architecture,3类NAS信令流程,1. 会话管理相关2. 位置管理相关3. 鉴权管理相关,3类NAS信令流程1. 会话管理相关,LTE典型信令过程课件,UE,eNB,MME,SGW,PGW,RRC: RRC Connection setup complete,NAS: Attach RequestNAS:PDN connectivity request,S1AP: Initial UE message,Authentication and NAS security proced

2、ure,HSS,S6a: Update Location request,S6a: Update Location answer,S11: Create bearer request,S5: Create bearer request,S5: Create bearer response,S11: Create bearer response,S1AP: Initial Context setup request,NAS: Attach acceptNAS: Activate Default EPS bearer request,NAS: Attach RequestNAS:PDN conne

3、ctivity request,RRC: RRCConnectionReconfiguration,NAS: Attach acceptNAS: Activate Default EPS bearer request,RRC: RRCConReconfigComplete,S1AP: Initial Context setup response,RRC: UL information Transfer,NAS: Attach completeNAS: Activate Default EPS bearer accept,S1AP: Uplink NAS Transport,NAS: Attac

4、h completeNAS: Activate Default EPS bearer accept,UEeNBMMESGWPGWRRC: RRC Connect,UE initiated Detach Procedure,UE,eNB,MME,SGW,PGW,HSS,RRC: RRC Connection setup complete,NAS: Detach request,S1AP: Initial UE message,NAS: Detach request,Authentication and NAS security,S11: Delete session request,S5: De

5、lete session request,S5: Delete session response,S11: Delete session response,S1AP: Downlink NAS transport,NAS: Detach accept,RRC: DLInformation transfer,NAS: Detach accept,Radio and S1 Release,S6a: TDelay purge timer expires,S6a: Purge UE request,S6a: Purge UE answer,UE initiated Detach ProcedureU,

6、UE Triggered Service Request Procedure,Initial UE Message,UE Triggered Service Request P,Network Triggered Service Request,Network Triggered Service Requ,TAU procedure,TAU procedure,Inter MME-TAU-message flow,Inter MME-TAU-message flow,Handover,Handover,Handover Air Interface,TYPES OF HANDOVER X2 Ba

7、sed Handover : without SGW change and with SGW change S1 Based Handover : with eNB, MME and SGW change,Handover Air InterfaceTYPES OF,X2 Handover,X2 is the interface between two eNBs and X2-AP is the protocols used for communication over it. The handover is directly performed between two eNodeBs.Han

8、dover takes place when the eNB detects that UE can no longer be served by it because of the power constraints.The MME is only informed at the end of the handover procedure once the handover is successfulThe release of resources at the source side is directly triggered from the target eNB.,X2 Handove

9、rX2 is the interface,RRC: Connection Reconfiguration Request,RRC: Connection Reconfiguration Complete,UE,S-eNB,T-eNB,MME,SGW,RRC: Measurement Control,X2AP: Handover Request,S11: Modify bearer request,S11: Modify bearer response,X2AP: SN Status Transfer,Sync,UL Allocation + TA for UE,UL Allocation,RR

10、C: Measurement Report,HandoverDecision,X2AP: Handover Response,UE Detach from old cell and syncto new cell,S1AP: Path Switch Request,S1AP: Path Switch Response,X2AP: UE Context Release,End Marker,SwitchDL Path,Data Forwarding,Data Forwarding,End Marker,FlushDL Buffer,RRC: Connection Reconfiguratio,S

11、1 Handover,This type of handover takes place when there is no X2 connectivity between source eNB and target eNB.Both eNBs are served by different MMEs. SGWs can also be different. Source eNB is served by source MME and source SGW while target eNB is served by target MME and target SGW. Source and ta

12、rget MMEs can communicate over S10 interface.All the handover decisions are taking place on S1 interface, its called as S1 based handover.,S1 HandoverThis type of handov,UE,T-eNB,S-MME,T-MME,T-SGW,S10: Forward Relocation Request,S11: Create Session Request,S11: Create Session Response,S1AP: eNB Stat

13、us Transfer,S1AP: Handover Required,S1AP: Handover Request,UE Detach from old cell and sync to new cell,S11: Modify Bearer Request,S1AP: UE Context Release Command,S-eNB,S-SGW,PGW,Handover Decision,S1AP: Handover Request Ack,S10: Forward Relocation Response,S1AP: Handover Command,RRC: Connection Rec

14、onfiguration,RRC: Connection Reconfiguration Complete,S1AP: Handover Notify,S11: Modify Bearer Response,S5: Modify Bearer Request,S1AP: UE Context Release Complete,S11: Delete Session Request,S11: Delete Session Response,S1AP: MME Status Transfer,S10: Forward SRNS Context Notification,S10: Forward S

15、RNS Context Ack,S10: Forward Relocation Complete,S10: Forward Relocation Complete Ack,S5: Modify Bearer Response,UET-eNBS-MMET-MMET-SGWS10: For,开始,开始,Before the UE can do anything, a Radio Resource Control connection must be established. The RRC is a logical connection between the UE and E-UTRAN. Th

16、ere are two different RRC states:RRC IDLERRC CONNECTED,Before the UE can do anything,RRC IDLE,This state indicates that there is no signaling radio bearer is established i.e. no RRC connection is established. The UE is considered RRC_IDLE once it obtains the center frequency, reads the timing inform

17、ation, syncs to the eNodeB, and is ready to receive system broadcast information.UE monitors a paging channel to detect incoming calls.UE can performs neighboring cell measurements and measurement reporting.,RRC IDLEThis state indicates t,RRC CONNECTED,This state indicates that there is signaling ra

18、dio bearer established i.e. RRC connection is established.Transfer of unicast data to/from an UE.The UE Monitors control channels associated with the shared data channel to determine if data is scheduled for it.The UE Provides channel quality and feedback information. The UE Perform neighboring cell

19、 measurements and measurement reporting.,RRC CONNECTEDThis state indica,Radio Resource Control (RRC) protocol states,RRC_IDLE state vs. RRC_CONNECTED state:UE does not have context in eNB and only Signalling Radio Bearer 0 (SRB0) is available for signalling between eNB and UE.UE has context in eNB a

20、nd communications between the UE and the network occurs on Signalling Radio Bearer 1 (SRB1) and Signalling Radio Bearer 2 (SRB2)UE generally has an id unique in the tracking area (S-TMSI = 40 bits long);UE generally has an id unique in the eNB area (C-RNTI = 40 bits long)UE may perform cell selectio

21、n/reselection without involvement from eNB;UE can perform handover (inter-eNB, intra-eNB, inter-RAT) under eNB control; UE can request connection establishment or re-establishment; eNB processes these requestsUE and eNBcan transmit and/or receive data to/from each other;UE listens for pages at speci

22、fic times (DRX, configured by MME); on request from the MME, eNB sends pages to the UE during UEs DRX up wake timeAt PDCP/RLC/MAC level:UE monitors L1/L2 control signalling channel to see if any transmission over the shared data channel has been allocated to the UEUE reports channel quality and feed

23、back information to eNBDRX/DTX period can be configured according to UE activity level for UE power saving and efficient resource utilization. This is under control of eNB (RRC).DRX = Discontinuous Reception; DTX = Discontinuous Transmission,Radio Resource Control (RRC) p,Control plane: Radio-interf

24、ace Related,PHY,MAC,RLC,PDCP,NAS,RRC,PHY,MAC,RLC,PDCP,RRC,NAS,UE,eNB,MME,L1,L2,IP,SCTP,S1-AP,L1,L2,IP,SCTP,S1-AP,eNB,MME,S1-MME,L1,L2,IP,SCTP,X2-AP,L1,L2,IP,SCTP,X2-AP,eNB,eNB,X2-C,Non-Access Stratum (NAS): The key control interface between MME and UERadio Resource Control (RRC): The main control in

25、terface between eNB and UEPacket Data Convergence Protocol (PDCP): Duplicate detection, ROHCRadio Link Control (RLC): Segmentation/re-assmebly, ARQ, acknowledge mode (AM)/ un-acknowledged mode (UAM), etcMedium Access Control (MAC): Access the channelPhysical Layer (PHY): Radio layer, eg modulation e

26、tc.,S1-AP: S1-Application ProtocolX2-AP: X2-Application ProtocolSCTP: Stream Control Transmission Protocol,Control plane: Radio-interface,状态转换图,状态转换图,RRC连接建立过程,RRC连接建立过程,UE,eNB,1. RRC连接建立准备阶段,RRC,RRC,RRC,RRC,RRC,RRC,2.CCCH:RRC连接请求,3.CCCH:RRC连接建立,4.DCCH:RRC连接建立完成,RRC连接建立过程示意图,UEeNB1. RRC连接建立准备阶段RRCRR

27、CRRCRR,1.准备阶段(1)UE用默认的物理信道参数来配置物理信道(2)UE为调度配置默认的半静态调度参数(3)UE配置默认的MAC主配置参数(4)UE配置CCCH参数(5)UE设置上行对齐定时器参数2.发RRC连接请求阶段(1)UE通过接入过程接入E-UTRAN,获得在UL_SCH信道上传数据的许可(2)设置UE标识(ue-Identity):S-TMSI或在0240 -1之间任选一个数(3)根据高层提供的RRC建立原因填写原因(establishmentCause信元)(4)通过PUSCH/UL_SCH/CCCH向E-UTRAN发RRC连接请求消息,消息中携带UE标识和建立原因3.接收

28、响应阶段E-UTRAN通过PDSCH/DL_SCH/CCCH想UE发RRC连接建立消息。UE收到RRC连接建立消息后，根据消息中的信元进行以下操作：（1）根据radioResourceConfigDedicated信元进行无线资源配置过程（2）填写RRC连接建立完成消息4.设置完成阶段UE通过PUCH/UL_SCH/DCCH向E-UTRAN发RRC连接建立完成消息,进入RRC连接状态,结束本次RRC连接建立过程,1.准备阶段,An example of a possible connection flow,UE,eNB,MME,Power ON, measurements, cell sele

29、ction,BCCH/BCH: MasterInformationBlock,BCCH/BCH: SystemInformation (SIB-1),BCCH/BCH: SystemInformation (SIB-2),RACH: preamble_id,PDCCH: UL grant,CCH: SRB0: RRCConnectionRequest (S-TMSI),CCH: SRB0: RRCConnectionSetup (S-TMSI, C-RNTI),DCCH: SRB1: RRCConnectionSetupComplete (C-RNTI, NAS_info),S1: INITI

30、AL UE MESSAGE,S1: INITIAL CONTEXT SETUP REQUEST (UE cap),DCCH: SRB1: Security Mode Command,DCCH: SRB1: Security Mode Complete,DCCH: SRB1: RRCReconfigurationRequest,DCCH: SRB1: RRCReconfigurationComplete,An example of a possible con,Random Access Procedure Contention Based (Initial Access Example),Th

31、e four steps of the RACH procedures are:1)(MSG. 1) Random Access Preamble on RACH in uplink: 6 bits to carry: a 5 bit random ID, and 1 bit to indicate information on size of message 3 limited by radio conditions.2)(MSG. 2) Random Access Response in downlink:semi-synchronous (within a flexible window

32、) with message 1;No HARQ;Sent on DL-SCH, and intended for one or multiple UEs3)(MSG. 3) RRC Connection Request in uplink:Uses HARQ;RLC TM: no segmentation;If the size of the message allows it, the initial NAS message (or something allowing to build the initial NAS message in eNB) can be included;Con

33、veys UE identityat least NAS UE identifier (initial access), or C-RNTI (other cases) 4)(MSG. 4) RRC Contention Resolution on DL-SCH:Not synchronous with message 3.HARQ is applied;UE identity, as provided in message 3 is echoed in RRC Contention Resolution message HARQ feedback is transmitted only by

34、 the UE which detects its own UE identity,Random Access Procedure Cont,RRC连接释放过程由E-UTRAN发起,要求一个处于RRC连接状态的UE释放RRC连接,包括释放已建立的无线承载(RB)和所有无线资源RRC连接重配置过程E-UTRAN通过向UE发RRC连接重配置消息,发起RRC连接重配置过程。当要求建立，修改，释放RB，或进行切换，或建立，修改，释放测量时，使用RRC连接重配置过程来修改RRC连接。RRC连接重配置消息中包括测量配置，移动控制，无线资源配置（包括RB，MAC主配置和物理信道配置）等消息以及所有相关的专用

35、NAS信息和安全配置信息。 RRC连接重配置消息以及RRC连接重配置完成消息使用SRB1且承载在DCCH逻辑信道上,RRC连接释放过程,E-UTRAN 附着,E-UTRAN 附着,UE,eNB,MME,SGW,PGW,1.RRC: RRC Connection setup complete,NAS: Attach RequestNAS:PDN connectivity request,2.S1AP: Initial UE message,3.Authentication and NAS security procedure,HSS,4.S6a: Update Location request,

36、5.S6a: Update Location answer,6.S11: Create bearer request,7.S5: Create bearer request,8.S5: Create bearer response,9.S11: Create bearer response,10.S1AP: Initial Context setup request,NAS: Attach acceptNAS: Activate Default EPS bearer request,NAS: Attach RequestNAS:PDN connectivity request,11.RRC:

37、RRCConnectionReconfiguration,NAS: Attach acceptNAS: Activate Default EPS bearer request,12.RRC: RRCConReconfigComplete,13.S1AP: Initial Context setup response,14.RRC: UL information Transfer,NAS: Attach completeNAS: Activate Default EPS bearer accept,15.S1AP: Uplink NAS Transport,NAS: Attach complet

38、eNAS: Activate Default EPS bearer accept,UEeNBMMESGWPGW1.RRC: RRC Conne,UE附着到E-UTRAN中时，要建立一个默认的EPS承载，该承载使UE获得一个“总是在线”的IP连接1. UE发起附着过程，向eNodeB发一个RR消息（RRC连接配置完成消息），消息中携带高层的附着请求消息。包括以下参数：UE的IMSI，旧的GUTI以及附加GUTI：旧GUTI可以由P-TMSI和RAI(routing area identity)导出。如果UE没有一个有效的GUTI或P-TMSI，则必须提供IMSI；如果IMSI也没有，则必须提供M

39、E的设备标识（IMEI）上一次访问的TAI：如果UE中保存有上一次访问的TAI，则应该把该参数提供给MMEUE核心网能力：描述UE的能力，包括支持的NAS和AS安全算法UE专用DRX参数：在接入过程中MAC为UE分配的DRX参数PDN类型：表示请求的IP地址类型（IPv4,IPv6,IPv4/IPv6)协议配置选项PCO：用于在UE和P-GW之间传输参数，比如UE希望的地址分配方式加密选项传输标志位附着类型：可以设为“切换”，“附着”，“紧急附着”KSIASME，NAS序列号，NAS-MAC此外，还携带两个RRC参数：被选网络，旧GUMMI2. eNodeB根据收到附着请求消息中的RRC参数进

40、行配置,并向MME转发附着请求消息(通过S1AP消息:初始UE消息),UE附着到E-UTRAN中时，要建立一个默认的EPS承载，该,3.身份ID请求和响应,NAS鉴权和安全功能激活,ME标识校验请求和确认4.MME向HSS发一个更新位置请求消息,告诉HSS目前在该MME中UE(由IMSI标识)正在发起附着5.HSS通过更新位置确认消息向MME提供该UE的签约数据(包括一个或多个PDN签约上下文)。MME正式确认UE驻留在某个TA中，并为该UE生成上下文6.MME向S-GW发生成默认承载请求消息,要求S-GW为该UE生成一个默认承载7.S-GW在其EPS承载列表中建立一个新的条目,并向P-GW发

41、送生成默认承载请求消息,要求P-GW为该UE生成一个默认承载8.P-GW在其EPS承载列表中建立一个新的条目,开始在外部PDN网络和S-GW之间转发用户面PDU,并生成一个新的计费ID,开始计费。P-GW向S-GW发送默认承载建立响应消息，其中包含给UE分配的PDN地址9.S-GW向MME发默认承载建立响应消息,通知MME默认承载已经建立,3.身份ID请求和响应,NAS鉴权和安全功能激活,ME标识校,10.MME通知eNodeB(通过S1AP的初始上下问建立请求消息)UE的附着请求已经被接受,并要求建立一个初始上下文11.eNodeB通知UE附着请求已经被接受(通过RRC连接重配置消息)12.

42、UE进行RRC连接重配置,完成后,向eNodeB回复一个RRC连接重配置完成消息13.eNodeB向MME回复一个初始上下文建立响应消息14.UE通过RRC的上行信息传输消息向eNodeB发一个NAS消息:附着完成消息,这标志着UE侧和附着相关的操作及设置已经完成15.eNodeB通过S1AP的上行NAS传输消息向MME转发UE的附着完成消息。本步后,一旦UE获得PDN地址,UE就想eNodeB发上行分组数据,这些分组数据可以通过隧道传到S-GW和P-GW更新承载请求及响应在MME S-GW P-GW之间完成后,EPS承载的E-UTRAN部分和EPC部分就连起来了,这时候下行分组数据也开始传送

43、了,10.MME通知eNodeB(通过S1AP的初始上下问建立请,会话管理过程UE和网络都能发起服务请求过程.UE发起的主呼,UE被叫以及网络发起ECM空闲态,UE的去附着都属于服务请求,会话管理过程,UE Triggered Service Request Procedure,Initial UE Message,UE Triggered Service Request P,UE触发的服务请求过程(1)UE向MME发送服务请求消息(为NAS消息,封装在给eNodeB的RRC消息中,如上行信息传输消息或RRC连接建立完成消息)(2)eNodeB向MME转发该NAS消息(封装在S1AP的初始UE

44、消息中,初试UE消息携带了服务小区的TAI和ECGI),如果MME不能处理服务请求,则会拒绝服务请求(3)NAS 鉴权(4)MME通过S1AP向eNodeB发初始上下文建立请求消息,包含上行到S-GW的隧道端口号和地址,要求激活的所有EPS的S1承载和无线承载.(5)eNodeB发起无线承载建立过程(6)UE的上行链路数据通过eNode转发给S-GW(7)eNodeB通过S1AP向MME发初始上下文建立完成消息,其中携带下行到eNodeB的S1-U隧道端口号和地址(8)MME向S-GW发更新承载请求消息,告之下行的S1-U TEID和基站地址,以建立下行S1承载.MME从这一步开始能给UE传下

45、行数据(9)如果RAT类型改变,S-GW还要向P-GW发更新承载请求消息(10)如果配置了PCC,P-GW要和PCRF交互获得不同的RAT的PCC规则,如果没有配置动态PCC,P-GW可以使用本地QoS策略(11)P-GW向S-GW回复更新承载响应消息(12)S-GW向MME回复更新承载响应消息,UE触发的服务请求过程,Network Triggered Service Request,Network Triggered Service Requ,网络触发的服务请求当MME需要给在ECM空闲态的UE发消息,如进行MME/HSS发起的去附着过程,或有下行数据到达,要求S-GW生成或修改专用承载,

46、在MME会发起网络触发的服务请求过程(1)当S-GW收到一个给UE的下行分组数据包,但S-GW的UE上下文中又没有下行用户面的TEID,表示当前没有和UE建立用户面连接,则S-GW缓存下行分组数据包,并查询目前服务UE的是哪个MME(SGSN)(2a)S-GW向MME(SGSN)发下行数据到达通知消息,请求用户面连接(2b)MME(SGSN)向S-GW发下行数据到达通知确认消息(3)如果UE注册到MME,则MME向UE注册TA的所有eNodeB发寻呼消息(4)如果eNodeB收到MME的寻呼消息,则开始寻呼UE(5)一旦收到E-UTRAN的寻呼消息,UE发起” UE触发的服务请求过程”(6)如

47、果ISR是激活的,当E-UTRAN收到寻呼响应,S-GW向MME发停止寻呼消息,网络触发的服务请求,切换过程,切换过程,RRC连接状态的UE在E-UTRAN中进行移动的一般原则如下在E-UTRAN中,网络控制UE的移动,网络决定UE该进入哪个小区,哪个频点或哪个RAT。根据无线条件或负载情况等，网络会触发切换过程。在给UE发送切换消息之前，源eNodeB为切换准备一个或多个目标eNodeB。目标eNodeB生成用于进行切换的消息，消息中包括目标小区的接如层详细配置信息，源eNodeB把该消息透穿给UE。等合适的时候，源eNodeB发起DRB的转发。接到切换消息后，UE在第一个可用的RACH时刻

48、就开始尝试接入到目标小区，也就是说，切换是异步的。因此，如果目标小区为这个随机接入分配了一个专用前缀（Preamble)，应该确保其在UE的第一个可能的RACH时刻就可用。一旦完成切换，UE给目标eNodeB发一个切换完成确认消息。源eNodeB中会保留UE的上下文一段时间，以防UE切换失败返回。检测到切换失败后，UE尝试在源小区或另一个也做好准备的小区使用RRC连接重建立过程，重新发起RRC连接。,RRC连接状态的UE在E-UTRAN中进行移动的一般原则如下,RRC: Connection Reconfiguration Request,RRC: Connection Reconfigura

49、tion Complete,UE,S-eNB,T-eNB,MME,SGW,RRC: Measurement Control,X2AP: Handover Request,S11: Modify bearer request,S11: Modify bearer response,X2AP: SN Status Transfer,Sync,UL Allocation + TA for UE,UL Allocation,RRC: Measurement Report,HandoverDecision,X2AP: Handover Response,UE Detach from old cell a

50、nd syncto new cell,S1AP: Path Switch Request,S1AP: Path Switch Response,X2AP: UE Context Release,End Marker,SwitchDL Path,Data Forwarding,Data Forwarding,End Marker,FlushDL Buffer,RRC: Connection Reconfiguratio,Source eNB keeps asking UE for the power measurements in a RRC measurement control messag