LTE系统全网信令流程.docx

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1、 LTE系统全网信令流程IntroductionAs a new wireless mobile communication technology, LTE (Long Term Evolution) provide all kinds of services through network access procedures. So when you are trying to understand the LTE technology, the network access procedure is just in the close front of your eyes.This doc

2、ument is trying to describe the general procedure handlings among the network elements under LTE network architecture, by way of showing you the procedure handlings in figures. From these figures, you will get an overview of the LTE general procedures, such as: “The System Information Handling, uThe

3、 Random Access Procedure,5 ttThe Attach Procedure5, ttThe TAU Procedure5, uThe Handover Procedure55, etc.The first several figures show the introduction of protocol layer stacks among network elements, such as: protocol layer stacksubetween UE-MME, ubetween UE-PDN GW,5 etc. From these protocol layer

4、 stacks introduction, you will learn the peer-to-peer protocol layers among several related network elements, it will help you to understand LTE procedures working mechanism stuff. And after, begins the description of the LTE general procedure, in an order from uSystem information handling,to “ANR M

5、easurement procedure55, with the ttaccess ProCedUre”，“handover procedure55, tInter-RAT operation procedure,5 in the middle. From these procedure figures description, you can get the deep details of the LTE network access procedure, and it will finally direct you to found a wholesystem-view of LTE ar

6、chitecture.This document is suitable for the guys who want to know the LTE general procedure, or use it as a reference book.2009-11-06LTE PDU L3 R&D TeamAbbreviationsMMEMobiHty ManageInent EntityUEUSer EqUiPmentMSMobile StationeNodeBevolved NodeBGWGateWayPCRFPoliCy and Charging RUleS FUCtiOnH-PCRFHo

7、me-PCRFV-PCRFVisited-PCRFHSSHome Subscriber ServerEIREqUiPmentldentity RegiSterUTRANUniversal Terrestrial Radio Access NetworkE-UTRANevolved UTRANGERANGSM/EDGE Radio Access NetworkPLMNPublic Land Mobile NetworkHPLMNHome PLMNVPLMNVisited PLMNHLRHome LoCation RegiSterVLRViSitor LoCation RegiSterCBCCel

8、l Broadcast CentreOMCODeration and MaintenanCe CenterBSCBase Station ControlerBTSBase Transceiver StationBSSBaSe Station SLlbSyStemCNCore NetworkMSC/SGSNMobile-services Switchina Centre/Servina GPRS SUDDort NodeInter-RATRadio ACCeSS TeChnolOgyMBMSMedia Broadcast and MUItiCaSt SyStemMCEMUIti-CelI/mul

9、ticast Coordination EntityRNCRadio Network ControlerNetwork elements functionseNodeB functions:- Header compression and user plane ciphering;- MME selection when no roteing to an MME can be determined from the information provided by the UE;- UL bearer level rate enforcement based on UE-AMBR and MBR

10、 via means of uplink scheduling (e.g. by limiting the amount of UL resources granted per UE overtime);- DL bearer level rate enforcement based on UE-AMBR;- UL and DL bearer level admission control;- Transport level packet marking in the uplink, e.g. setting the DiffServ Code Point, based on the QCI

11、of the associated EPS bearer.MME functions:- NAS signalling;- NAS signalling security;- Inter CN node signalling for mobility between 3GPP access networks (terminating S3);- UE Reachability in ECM-IDLE state (including control and execution of paging retransmission);- Tracking Area list management;-

12、 PDN GW and Serving GW selection;- MME selection for handovers with MME change;- SGSN selection for handovers to 2G or 3G 3GPP access networks;- Roaming (S6a towards home HSS);- Authentication;- Authorization;- Bearer management functions including dedicated bearer establishment;- Lawful Interceptio

13、n of signalling traffic;- Warning message transfer function (including selection of appropriate eNB);- UE Reachability procedures.SGSN functions:- Inter EPC node signalling for mobility between 2G3G and E-UTRAN 3GPP access networks;- PDN and Serving GW selection: the selection of S-GW/P-GW by the SG

14、SN is as specified for the MME;- MME selection for handovers to E-UTRAN 3GPP access network.Serving GW functions:- the local Mobility Anchor point for inter-eNodeB handover;- sending of one or more end marker to the source eNodeB, source SGSN or source RNC immediately after switching the path during

15、 inter-eNodeB and inter-RAT handover, especially to assist the reordering function in eNodeB.- Mobility anchoring for inter-3GPP mobility (terminating S4 and relaying the traffic between 2G3G system and PDN GW);- ECM-IDLE mode downlink packet buffering and initiation of network triggered service req

16、uest procedure;- Lawful Interception;- Packet routeing and forwarding;- Transport level packet marking in the uplink and the downlink, e.g. setting the DiffServ Code Point, based on the QCI of the associated EPS bearer;- Accounting for inter-operator charging. For GTP-based S5S8, the Serving GW gene

17、rates accounting data per UE and bearer;- Interfacing OFCS according to charging principles and through reference points specified in TS 32.240 51.PDN GW functions:- Per-user based packet filtering (by e.g. deep packet inspection);- Lawful Interception;- UE IP address allocation;- Transport level pa

18、cket marking in the uplink and downlink, e.g. setting the DiffServ Code Point, based on the QCI of the associated EPS bearer;- Accounting for inter-operator charging;- UL and DL service level charging as defined in TS 23.203 6(e.g. based on SDFs defined by the PCRF, or based on deep packet inspectio

19、n defined by local policy);- Interfacing OFCS through according to charging principles and through reference points specified in TS 32.240 51 .- UL and DL service level gating control as defined in TS 23.203 6;- UL and DL service level rate enforcement as defined in TS 23.203 6(e.g. by rate policing

20、/shaping per SDF);- UL and DL rate enforcement based on APN-AMBR(e.g. by rate policing/shaping per aggregate of traffic of all SDFs of the same APN that are associated with Non-GBR QCIs);3Network elements functions- DL rate enforcement based on the accumulated MBRs of the aggregate of SDFs with the

21、same GBR QCI(e.g. by rate policing/shaping);- DHCPv4 (server and client) and DHCPv6 (client and server) functions;- The network does not support PPP bearer type in this version of the specification. Pre-Release 8 PPP functionality of a GGSN may be implemented in the PDN GW;- packet screening.- UL an

22、d DL bearer binding as defined in TS 23.203 6;- UL bearer binding verification as defined in TS 23.203 6;- Functionality as defined in RFC 4861 32;- Accounting per UE and bearer.H-PCRF functions:- terminates the Rx reference point for home network services;- terminates the S9 reference point for roa

23、ming with local breakout;- associates the sessions established over the multiple reference points (S9, Rx), for the same UEs IP- CAN session (PCC session binding).- -PCRF functions:terminates the Gx and S9 reference points for roaming with local breakout;terminates Rx for roaming with local breakout

24、 and visited operators Application Function.网元间信令面总体协议栈Sl-APSl-APSCTPSCTP,IPIPL2L2LILIeNodeBSl-MMEMMEbetween eNodeB-MMENASNASRRCRRCRRCRRCPDCPPDCPPDCPSCTPRLCRLCRLCIPMACMACMACL2LILILILlUELTE-UueNodeBSl-MMEMMEbetween UE-MMEGTP-CGTP-CUDPUDPIPIPL2L2LlLlSGSNS3MMEbetween SGSN-MMEGTP-CGTP-CUDPUDPIPIPL2L2LlL

25、lSGSNS4S-GWbetween SGSN-Serving GWGTP-CGTP-CUDPUDPIPIPL2L2LILlS-GWS5 or S8P-GWbetween Sening GW-PDN GW网元间信令面总体协议栈（续）GTP-CGTP-CUDPIPUDPIPL2LIL2LlMMESlOMMEbetween MME-MMEGTP-CGTP-CUDPUDPIPIPL2L2LlLIMMESllS-GWbetween MME-Servring GWDiameterDiameterSCTPSCTPIPIPL2L2LlLlMMES6aHSSbetween MME-HSSDiameterDia

26、meterSCTPSCTPIPIPL2L2LILlMMESI3EIRbetween MME-EIReNodeB Sl-MME MMESBc CBCbetween CBC-eNodeB#网元间用户面总体协议栈ApplicationIPIPPDCPGTP-UPDCPGTP-UGTP-UGTP-URLCRLCUDPnPUDP1PUDPIPUDPnPMACMACL2L2L2L2LlLlLlLlLlLlUELTE-UueNodeBSI-UServing GWS5S8PDN GWSGibetween UE-PDN GWGTP-UGTP-UUDPUDPIPIPL2L2LILIMMESI-UMMEbetwee

27、n eNodeB-Serving GW79网元间用户面总体协议栈（续）ApplicationIPIPPDCPGTP-URLCUDP/IPMACL2LlLlIuUES4S5S8 PDN GW SGibetween UE-PDN GW with 3G access via S12PDCPGTP-URLCUDP/IPMACL2LlLlUTRANGTP-UGTP-UUDP/IPUDP/IPL2L2LlLlServing GWGTP-UGTP-UUDP/IPUDP/IPL2L2LlLlServing GW系统消息广播流程Special comments:The frozen data of fiduci

28、al 3GPP protocol version : 2009/09.System information handling:System information is divided into the MasterInformationBIock (MIB) and a number of SystemlnformationBIocks (SIBs). The MIB includes a limited number of most essential and most frequently transmitted parameters that are needed to acquire

29、 other information from the cell, and is transmitted on BCH. SIBs other than SystemlnformationBIockTypeI are carried in Systeminformation (SI) messages and mapping of SIBs to SI messages is flexibly configurable by SCheduIingInfoList included in SystemlnformationBIockTypeI, with restrictions that: e

30、ach SIB is contained only in a single SI message, only SIBs having the same scheduling requirement (periodicity) can be mapped to the same SI message, and SystemlnformationBlockType2 is always mapped to the SI message that corresponds to the first entry in the list of SI messages in ScheduIingInfoLi

31、st. There may be multiple SI messages transmitted with the same periodicity. SystemlnformationBIockTypeI and all SI messages are transmitted on DL-SCH.Reference:36.331: Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification;小区选择流程Special comments:Th

32、e frozen data of fiducial 3GPP protocol version : 2009/09.1) Initial Cell Selection:This procedure requires no prior knowledge of which RF channels are E-UTRA carriers. The UE shall scan all RF channels in the E-UTRA bands according to its capabilities to find a suitable cell. On each carrier freque

33、ncy, the UE need only search for the strongest cell. Once a suitable cell is found this cell shall be selected.2) Stored Information Cell Selection:This procedure requires stored information of carrier frequencies and optionally also information on cell parameters, from previously received measureme

34、nt control information elements or from previously detected cells. Once the UE has found a suitable cell the UE shall select it. If no suitable cell is found the Initial Cell Selection procedure shall be started.suitable cell:A suitable cell is a cell on which the UE may camp on to obtain normal ser

35、vice. Such a cell shall fulfil all the following requirements.- The cell is part of either:- the selected PLMN, or:- the registered PLMN, or:- a PLMN of the Equivalent PLMN listaccording to the latest information provided by NAS:- The cell is not barred- The cell is part of at least one TA that is n

36、ot part of the list of forbidden tracking areas for roaming, which belongs to a PLMN that fulfils the first bullet above;- The cell selection criteria are fulfilled;- For a CSG cell, the CSG ID is part of the allowed CSG list of the UE.If more than one PLMN identity is broadcast in the cell, the cel

37、l is considered to be part of all TAs with TAIs constructed from the PLMN identities and the TAC broadcast in the cell.Reference:36.331: Evolved Universal Terrestrial Radio Access (E-LITRA); Radio Resource Control (RRC); Protocol specification;36.304: Evolved Universal Terrestrial Radio Access (E-UT

38、RA);Equipment (UE) procedures in idle mode小区重选流程Special comments:The frozen data of fiducial 3GPP protocol version : 2009/09.Reselection priorities handling:1)Absolute priorities of different E-UTRAN frequencies or inter-RAT frequencies may be provided to the UE in the system information, in the RRc

39、ConnectionReIease message, or by inheriting from another RAT at inter-RAT cell (re)slection.2)ln the case of system information, an E-UTRAN frequency or inter-RAT frequency may be listed without providing a priority (i.e. the field CellReseIectionPriority is absent for that frequency). If priorities

40、 are provided in dedicated signalling, the UE shall ignore all the priorities provided in system information.3)lf UE is in camped on any cell state, UE shall only apply the priorities provided by system information from current cell, and the UE preserves priorities provided by dedicated signalling u

41、nless specified otherwise.4)When the UE in camped normally state, has only dedicated priorities other than for the current frequency, the UE shall consider the current frequency to be the lowest priority frequency (i.e. lower than the eight network configured values).5)The UE shall delete priorities

42、 provided by dedicated signalling when:- the UE enters RRC_CONNECTED state; or- the optional validity time of dedicated priorities (T320) expires; or- a PLMN selection is performed on request by NAS.6)The UE shall only perform cell reselection evaluation for E-UTRAN frequencies and inter-RAT frequen

43、cies that are given in system information and for which the UE has a priority provided.7)The UE shall not consider any black listed cells as candidate for cell reselection.8)The UE shall inherit the priorities provided by dedicated signalling and the remaining validity time (i.e., T320 in E-UTRA, T3

44、22 in UTRA and T3230, FFS in GERAN), if configured, at inter-RAT cell (re)selection.Reference:36.331: Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification;36.304: Evolved Universal Terrestrial Radio Access (E-UTRA);Equipment (UE) procedures in idl

45、e mode寻呼过程流程Network Trigged Service Request(Paging) procedure:If the MME needs to signal with the UE that is in ECM-IDLE state, e.g. to perform the MME/HSS-initiated detach procedure for the ECM-IDLE mode UE or the S-GW receives control signalling (e.g. Create Dedicated Bearer Request or Modify Dedicated Bearer Request), the MME starts network triggered service request procedure from step 3.If I