http://TelecomTutorial.info VoLTE SIM IMS Registration VoLTE Registration • LTE Attach • Default Vs Dedicated Bearer • IMS Bearer • SIP and IMS Registration • TAS Registration Disclaimer : Views expressed in this blog or Video are strictly mine and not of my employers or Equipment Manufacturers http://TelecomTutorial.info VoLTE Registration VoLTE UE Behavior 1. LTE Attach UE IMS 2. IMS Registration • Enables VoLTE Services LTE Network • Ex : Calls , SMS , Supplementary Services etc.. http://TelecomTutorial.info http://TelecomTutorial.info VoLTE IMS Registration 1 2 Default Internet EPS bearer LTE Attach 3 4 Default IMS EPS bearer SIP / IMS Registration Dedicated Bearer : MO / MT Calls 5 Default LTE Bearer Internet Default LTE Bearer SIP EPC LTE Network TAS CSCF IMS GW PSTN N/W Other IMS EPS bearer Default EPS Bearer • Established during LTE Attach • Allocate IP address to UE • Used for Always connected bearer :• Internet Connectivity ( QCI : 6-9 ) • SIP Signaling Connectivity ( QCI : 5 ) Dedicated EPS Bearer • Established during call • No IP Address Allocation • Linked to particular Default EPS Bearer • Have a specific (usually guaranteed) QoS • Used for On-Demand bearer for :• Voice Call ( QCI : 1 ) • Video Call ( QCI : 2 ) http://TelecomTutorial.info What if LTE Radio is Congested ?? Priority QCI 1 2 3 5 1 3 Resource Type non-GBR Guaranteed Bit Rate (GBR) Packet Delay Budget Packet Error Loss Rate 100ms 100ms 50ms 10−6 10−2 10−3 Volte , IMS Signaling Volte , Conversational Voice Real Time Gaming, V2X messages 150ms 10−3 Volte , Conversational Video (Live Streaming) Non-Conversational Video (Buffered Streaming) 4 2 5 4 300ms 10−6 6 7 8 6 7 8 300ms 100ms 300ms 10−6 10−3 10−6 9 9 300ms 10−6 non-GBR Best Effort Example Services Internet Services , Video (Buffered Streaming) TCP-Based (for example, www, email, chat, ftp, p2p and the like) http://TelecomTutorial.info VoLTE UE Attach and IMS Registration LTE Bearer Default Bearer QCI = 6 Internet Internet Default Bearer QCI = 5 SIP Registration SIP CSCF EPC LTE Network IMS Dedicated Bearer QCI = 1 Voice Call TAS GW PSTN N/W Other IMS http://TelecomTutorial.info LTE Attach & Default Internet EPS Bearer HSS 1 Default Internet EPS bearer 2 Default IMS EPS bearer 3 SIP / IMS Registration 4 Dedicated Bearer : MO / MT Calls 5 PCRF Location Update LTE Attach Create Session request Attach Request Attach Accept MME UE Create Session resp. SAE GW UE found IMS Service is supported MME found subscriber can support SRVCC VoPS = Yes SRVCCOperation Internet APN http://TelecomTutorial.info Default IMS EPS bearer LTE Attach 1 Default Internet EPS bearer 2 Default IMS EPS bearer 3 SIP / IMS Registration 4 Dedicated Bearer : MO / MT Calls 5 http://TelecomTutorial.info PCRF Create Session request PDN Connection Request UE Activate Default Bearer Request IMS MME Create Session resp. Return P-CSCF IP SAE GW IMS APN SIP Registration : 1st Attempt HSS Cx: UAR (IMPI) Cx: MAR Cx: MAA (rand, xres,ck,ik,autn) Cx: UAA (Server Capabilities) Mw: SIP REGISTER (ATCF STN-SR) Gm : SIP REGISTER (IMPI,IMPU, IP@) UE Gm: 401 Unauthorized (nonce) P-CSCF Mw: 401 Unauthorized. Mw: SIP REGISTER I-CSCF Authenticate UE Send Challenge http://TelecomTutorial.info Mw: 401 Unauthorized. S-CSCF 401 Error SIP Registration : 2nd Attempt LTE Attach 2 Default IMS EPS bearer 3 Dedicated Bearer : MO / MT Calls Cx: UAR (IMPI) 1 Default Internet EPS bearer SIP / IMS Registration HSS Cx: SAR Cx: SAA Cx: UAA (scscf) Gm: SIP REGISTER (IMPI,IMPU, nonce, RES) UE Mw: 200 OK 4 5 Download subscriber service profiles Mw: SIP REGISTER (ATCF STN-SR) P-CSCF Rx: AAR Rx: AAA I-CSCF Mw: 200 OK (path: p-cscf, atcf s-cscf) PCRF IMS Signaling bearer Supervision UE registered in S-CSCF Mw: SIP REGISTER Mw: 200 OK (path: pcscf, atcf) S-CSCF Success Regn. http://TelecomTutorial.info SIP Registration : TAS Update LTE Attach Default Internet EPS bearer Default IMS EPS bearer SIP / IMS Registration Dedicated Bearer : MO / MT Calls 1 ISC: SIP REGISTER (ATCF STN-SR,ATCFMgmt-uri, ATCF-Path) 2 3 4 5 http://TelecomTutorial.info SIP Basic Data TAS Sh: UDR (Repository Data) Sh: UDA MAP Messages ( RD & ISD ) S-CSCF ISC: 200 OK (REGISTER) Supplementary Service Data HSS TAS Regn. SIP Registration : TAS Update LTE Attach 1 Default Internet EPS bearer 2 Default IMS EPS bearer 3 SIP / IMS Registration 4 Dedicated Bearer : MO / MT Calls Ready http://TelecomTutorial.info