UTRAN Procedures Elementary procedures Paging g RRC connection setup Transaction reasoning Authentication and security control Transaction setup with RAB allocation Transaction clearing and RAB release RRC connection release RRM procedures Radio link addition and deletion Intersystem t handover from UMTS to GSM (CS/PS) UE state transitions/ bearer reconfiguration MM procedures -> see MM slides CM procedures -> see CM slides References: Kaaranen ch. 10 (simple cases discussed here) 3GPP TR 25.931 (more complicated cases) 1
Basic Model of UMTS Network Transactions Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release A transaction comprises all the elementary procedures required to enable the transport of user data (PS or CS mode) or the exchange of higher-layer signaling messages (e.g. MM or CM) UE indicates the CN the requested service Allocation of bearers to support required UMTS bearer service Transfer of data Release of all bearers to support UMTS bearer service 2
Paging Paging type 1: UE idle mode (no RRC connection) RRC connected modes cell_pch or URA_PCH Example: paging for a UE in idle mode Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release UE N ode B N ode B RNC RNC CN 1.1 2.1 1 2 1. Paging 1. Paging (Requesting CN domain, IMSI,...) 2. PCCH : Paging Type 1 3. PCCH : Paging Type 1 3
Paging Paging type 2: UE is in RRC connected mode cell_dch or cell_fach Paging request est from another CN domain Example: paging g for a UE in RRC Connected Mode (CELL_DCH or CELL_FACH state) Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release UE Serving RNC CN 1. Paging RRC 2. DCCH : Paging Type 2 RRC 2 cases: UTRAN coordinates the paging request with the existing RRC connection (given example) UE coordinates the paging request with the existing RRC connection 4
RRC Connection Setup UE Node B RNC CN UE_Idle Initial Random Access CCCH (TM)/ RACH: RRC Connection Request RL Setup Request Addr.: Initial UE ID Request for DCCH Incl. Establishment cause Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release RL Setup Response ALCAP Iub Transport bearer Setup Establishment of futran DCH resources incl. CAC UL/DL Synchronisation CCCH (UM)/ FACH: RRC Connection Setup Addr.: Initial UE ID CELL_DCH DCCH (AM)/ DCH: RRC Connection Setup Complete Addr.: by DCH DCCH established UE capabilities known Establishment of a RRC connection in cell_dch mode 5
Initial Random Access UE Node B Controlling RNC Persistency check before Preamble Preamble Preamble Acquisition Indication (AICH) Resourcing Node B Hardware PRACH Message CRC Check RACHFP RACH Message [RRC Connection Request] RACHFP UE addressing CCCH: UE ID embedded in the RRC message DTCH/ DCCH: UE ID included in MAC header 6
RRC Connection Setup Reasons for RRC connection setup: Call setup (mobile-originated and mobile-terminated calls) Conversational call Streaming call Interactive call Background call Emergency call Call re-establishmentestablishment Exchange of signaling messages (low/high priority) RRC connection request message contains, e.g. IMSI, TMSI, IMEI Location area, routing area identity, etc. Other information: e.g. HSDPA/ E-DCH UE capability, standards release 7
Paging NAS Signaling Connection Establishment (Transaction Reasoning) Transaction Reasoning RRC Connection Establishment (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release UE Serving RNC CN 1. RRC Connection Establishment RRC 2. DCCH : Initial Direct Transfer RRC 3. Initial UE Message Payload contains system network message: Information about the transaction initiated by the UE (IMSI, TMSI, location area, kind of requested transaction) 8
Authentication and Security Control Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release Authentication request/response: mutual authentication of UE and network Security mode command/complete: CN domain indicates to UTRAN and UE the encryption details (method/algorithms and encryption keys) 9
Transition Setup and RAB Establishment (CS Mode) Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release 10
Transition Setup and RAB Establishment (PS Mode) Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release 11
RAB Establishment UE NodeB SRNC CN Activation Time, T Activation Cell_DCH/ Cell FACH RAB Assignment ALCAP Iu Transport Bearer Establishment Radio Link Reconfiguration Prepare When Cell_FACH: RL Setup Radio Link Reconfiguration Ready ALCAP Iub Transport Bearer Establishment Node B RNC Data Transport Bearer Sync Radio Link Reconfiguration Commit Radio Bearer Setup Radio Bearer Setup Complete RAB Assignment Response When CS CN Cell DCH Example: Synchronised establishment of a RAB on DCH 12
Transaction Release and RAB Release (CS Mode) Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release Note: signaling connection and RRC connection remains 13
Transaction Release and Iu Release (CS Mode) Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release Note: signaling connection and RRC connection are released 14
Transaction Release and RAB Release (PS Mode) Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release Note: signaling connection and RRC connection remain 15
Transaction Release and Iu Release (PS Mode) Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release Note: signaling connection and RRC connection are released 16
RRC Connection Release Paging RRC Connection Establishment Transaction Reasoning (Signaling conn. establishment) Authentication and Security Transaction Setup and RAB Allocation Transaction (user or control plane) Transaction Release and RAB Release RRC Connection Release 17
RRC Connection Release (involving DRNC) Example: RRC connection release of a dedicated channel in soft HO mode with DRNC UE N ode B N ode B Drift Serving D rift RNS Serving RNS RNC RNC CN 1. Iu Release Command 2. Iu Release Complete 3. ALCAP Iu Bearer Release RRC RRC 4. RRC Connection Release 5. RRC Connection Release Complete RRC RRC N BAP 6. Radio Link Deletion N B AP RNSAP 7. Radio Link Deletion RN S AP N BAP 8. Radio Link Deletion N BAP N BAP 9. Radio Link Deletion Response N B AP NBAP 10. Radio Link Deletion Response NBAP 11. Radio Link Deletion Response RNSAP RN S AP 12. ALCAP Iub Bearer Release 13. ALCAP Iub Bearer Release ALCAP Iur Bearer Release 18
Soft Handover Radio Link Addition UE Target Node B DRNC SRNC Radio Link Add/ Setup Request Radio Link Add/ Setup Request RNC Decides to add a new Radio Link start Rx Radio Link Add/ Setup Response RadioLinkAdd/SetupResponse Response ALCAP Iub Data Transport bearer Setup Radio Link Restore Indication start Tx Active Set Update (Radio Link Addition) ALCAP Iur bearer Setup Radio Link Restore Indication When RL Setup Target Node B is ready Active Set Update Complete UE starts Rx on new radio link Measurement Control E.g. new neighbour cell list Unsynchronized addition 19
Soft Handover Radio Link Deletion UE Node B DRNC SRNC Active Set Update (Radio Link Deletion) RNC Decides to delete an existing Radio Link UE stops Rx on old radio link Active Set Update Complete Measurement Control E.g. new neighbour cell list Radio Link Deletion Request Radio Link Deletion Request Free-up resources of old NodeB stop Rx & Tx Radio Link Deletion Response Radio Link Deletion Response ALCAP Iub Data Transport bearer Release ALCAP Iur bearer Release Unsynchronized deletion 20
Inter-system Handover (UMTS to GSM) UE SRNC 3G MSC 2G MSC BSC RNC Decides to perform HO to GSM Relocation Required MAP Prepare HO Req. HO Request HO Request ACK Channel activation procedure in BSS MAP Prepare HO Response UE switches to GSM BSS HO from UTRAN Command Relocation Command Radio Link Failure in UTRAN and Radio Link Establishment in GSM BSS HO Complete HO Complete MAP Send End Signal Req. Free up of Resources Iu Release Procedure MAP Send End Signal Resp. 21
UTRAN Initiated UMTS-GPRS Cell Reselection UE Serving RNC SGSN 1. UTRAN decision to perform Cell Change Order from UTRAN: RRC 2. Cell Change Order from UTRAN RRC 3. The UE accesses the GSM system and initiates routing area 4. SRNS Context Request update. The packet context is transferred to the new SGSN. 5. SRNS Context Response 6. Iu Release Command 7. Iu Release Complete Most signalling between 2G and 2G CN 22
SRNS Relocation (CS) 23
UE RRC Connected States Cell FACH optional Data activity High traffic or CS call URA PCH No data No data Low traffic Cell DCH Dynamic RB reconfigure Data activity Cell_DCH Dedicated Traffic and Control carried over DCH Cell_FACH Dedicated Traffic and Control carried over RACH/ FACH URA_PCH No air interface resources required, dormant RB UE receives paging on UTRAN Routing Area (URA) basis rather than standard routing area (RA); URA usually in the order of 10 cells 24
URA_PCH to CELL_DCH/ CELL_FACH Transition UE Node B SRNC URA PCH UE temporary in CllFACH Cell_FACH Cell Update (CCCH, RACH, TM, cause paging response or Uplink Data transmission ) Radio Link Setup request If Cell_DCH Incl. DBC check UE Transitions to Cell DCH/ stays in Cell_FACH UE Sends Complete Message Cell_DCH/ Cell_FACH Cell Update Confirm(CCCH, FACH, UM) Radio Link Setup response ALCAP Iub Data Transport bearer Setup Radio Link Restore Indication Cell_DCH: Radio Bearer Reconfiguration Complete (DCCH AM, DCH) Cell_FACH: UTRAN Mobility Confirm (DCCH AM, RACH) L2 ACK (DCCH) For each DCH, separately tl Incl. UL/ DL Synch. RRC State Indicator Cell_DCH/ URA_FACH T Activation = NOW Unsynchronised procedure with CRNC = SRNC 25
CELL_FACH to CELL_DCH Transition UE Node B RNC CN Cell FACH Radio Link Setup request Radio Link Setup response RNC determines UE should transition to Cell DCH ALCAP for both DCH UE Transitions to Cell DCH UE Sends Complete Message on DCH CllDCH Cell FP Synch Radio Bearer Reconfiguration (DCCH, FACH) Rdi Radio Link LikRestore Indication Idi i Radio Bearer Reconfiguration Complete (DCCH AM, DCH) L2 ACK (DCH) RNC Stops MAC-d Transmission to UE Unsynchronised procedure with CRNC = SRNC 26
CELL_DCH to URA_PCH/ CELL_FACH Transition UE Node B SRNC UE transitions to Cell_ FACH and reads SIB Cell DCH Radio Bearer Reconfiguration (DCCH, DCH, UM) Radio Bearer Reconfiguration Complete(DCCH, RACH, AM) RRC State Indicator Cell_FACH/ URA_PCH UE Sends Complete Message on RACH Cell_FACH/ URA_PCH L2 ACK (DCCH, FACH) RNC leaves time for L2 ACK being errored Radio Link Deletion Request Radio Link Deletion Response Free-up non-used DCH Resources ALCAP Iub Data Transport Bearer Release Unsynchronised procedure with CRNC = SRNC 27
Dynamic Bearer Reconfiguration UE Cell DCH Activation Time, T Activation UE & Node-B reconfigured to the new rates Cell DCH Node B (Drift RNS) Node B (Serving RNS) Rdi Radio Link LikReconfiguration Prepare DRNC Radio Link Reconfig Prepare Radio Link Reconfiguration Prepare Radio Link Reconfiguration Ready Radio Link Reconfig Ready Radio Link Reconfiguration i Ready ALCAP Iub Data Transport bearer Setup ALCAP Iur bearer Setup ALCAP Iub Data Transport bearer Setup Radio Link Reconfiguration Commit (T Activation ) Radio Link Reconfig commit (T Activation ) Radio Link Reconfiguration commit (T Activation ) Transport Channel Reconfiguration (DCCH, AM, T Activation ) Transport Channel Reconfiguration Complete (DCCH, AM) ALCAP Iub Data Transport bearer Release ALCAP Iur bearer Release ALCAP Iub Data Transport bearer Release SRNC RNC Decides to change the rate of the UE When rate increase All Node B s are ready Release the transport Network resources for the previous configuration Synchronised DCH modify w/o transport bearer reconfiguration 28