【正文】 LTE 典型信令過(guò)程 Software Architecture 3類(lèi) NAS信令流程 ? 1. 會(huì)話管理相關(guān) ? 2. 位置管理相關(guān) ? 3. 鑒權(quán)管理相關(guān) UE eNB MME SGW PGW RRC: RRC Connection setup plete NAS: Attach Request NAS:PDN connectivity request S1AP: Initial UE message Authentication and NAS security procedure 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 accept NAS: Activate Default EPS bearer request NAS: Attach Request NAS:PDN connectivity request RRC: RRCConnectionReconfiguration NAS: Attach accept NAS: Activate Default EPS bearer request RRC: RRCConReconfigComplete S1AP: Initial Context setup response RRC: UL information Transfer NAS: Attach plete NAS: Activate Default EPS bearer accept S1AP: Uplink NAS Transport NAS: Attach plete NAS: Activate Default EPS bearer accept UE initiated Detach Procedure UE eNB MME SGW PGW HSS RRC: RRC Connection setup plete NAS: Detach request S1AP: Initial UE message NAS: Detach request Authentication and NAS security S11: Delete session request S5: Delete 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 MME Se rv i n g G W PDN G W 2 . NAS: Se rv i c e Re q u e s t 1 . NAS: Se rv i c e Re q u e s t 7 . S1 AP: I n i ti a l Co n te x t Se tu p Co m p l e te 3 . Au th e n ti c a t i o n HSS 4 . S1 AP: I n i ti a l Co n te x t Se tu p Re q u e s t 5 . Rad i o Be a r e r Es t a b l i s h m e n t 6 . Upl i n k D a ta 8 . Upd a t e Be a r e r Re q u e s t 1 2 . Upd a te Be a re r Re s p o n s e UE e Nod e B 1 1 . Upd a te Be a re r Re s p o n s e PCR F (A ) 1 0 . P C E F I n it ia t e d I P C A N S e s s ion M o d if i c a t ion 9 . Upd a t e Be a r e r Re q u e s t UE Triggered Service Request Procedure Initial UE Message Network Triggered Service Request 1 . Dow n l i n k D a ta 2 a . Dow n l i n k Da ta N o ti f i c a ti o n MME S GW PDN G W 3 a . Pa g i n g 4 b . Pa g i n g 5 . UE Pa g i n g Re s p o n s e UE RN C/BSC 2 a . Dow n l i n k Da ta N o ti f i c a ti o n e Nod e B SG SN 2 b . Dow n l i n k Da ta N o ti f i c a ti o n Ac k 2 b . Dow n l i n k Da ta N o ti f i c a ti o n Ac k 3 b . Pa g i n g Dow n l i n k Da ta E UT RAN 6 a . Sto p Pa g i n g 6 b . Sto p Pa g i n g 4 a . Pa g i n g Dow n l i n k Da ta 3 G DT Dow n l i n k Da ta 2 G o r 3 G n o n DT TAU procedure U EM M ES t o p T 3 4 3 0O RT R A C K I N G A R E A U P D A T E R E Q U E S TS t a r t T 3 4 3 0S t o p T 3 4 5 0T R A C K I N G A R E A U P D A T E A C C E P TS t a r t T 3 4 5 0T R A C K I N G A R E A U P D A T E C O M P L E T ES t o p T 3 4 3 0T R A C K I N G A R E A U P D A T E R E Q U E S TS t a r t T 3 4 3 0T R A C K I N G A R E A U P D A T E R E J E C TI f G U T I a l l o c a t e d ,I f G U T I a l l o c a t e d ,Inter MMETAUmessage flow Handover Handover Air Interface TYPES OF HANDOVER ? X2 Based Handover : without SGW change and with SGW change ? S1 Based Handover : with eNB, MME and SGW change X2 Handover ?X2 is the interface between two eNB’s and X2AP is the protocols used for munication over it. ?The handover is directly performed between two eNodeB’s. ?Handover 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 successful ?The release of resources at the source side is directly triggered from the target eNB. RRC: Connection Reconfiguration Request RRC: Connection Reconfiguration Complete UE SeNB TeNB 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 Handover Decision X2AP: Handover Response UE Detach from old cell and sync to new cell S1AP: Path Switch Request S1AP: Path Switch Response X2AP: UE Context Release End Marker Switch DL Path Data Forwarding Data Forwarding End Marker Flush DL Buffer S1 Handover ?This type of handover takes place when there is no X2 connectivity between source eNB and target eNB. ?Both eNB’s are served by different MME’s. SGW’s 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 target MME’s can municate over S10 interface. ?All the handover decisions are taking place on S1 interface, its called as S1 based handover. UE TeNB SMME TMME TSGW S10: Forward Relocation Request S11: Create Session Request S11: Create Session Response S1AP: eNB Status 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 SeNB SSGW PGW Handover Decision S1AP: Handover Request Ack S10: Forward Relocation Response S1AP: Handover Command RRC: Connection Reconfiguration RRC: Connection Reconfiguration Complete S1AP: Handover Notify S11: Modify Bearer Response