3GPP presentation Architecture evolution Moscow, October 2008 3GPP TSG CT Chairman Hannu Hietalahti 1 Contents Migration from GSM to multi-access IP multimedia • From GSM to multi-access • SIM/USIM/ISIM support • Security evolution • System Architecture Evolution (SAE) • IMS • Multi-mode terminals and networks – – – – – Service continuity Multiple registration Voice Call Continuity CS Fallback Network selection 2 From GSM to multi-access Continuous improvement of access technologies Provision of services over any access network Gb GERAN Iu Visited Network GPRS Core Home Network vPCRF hPCR F SGSN S7 UTRAN Common Core network S9 S3 Rx + S4 HSS S6 S7 S6 S1 Evolved RA N MME UP E S5a Home Inter AS Anchor S8 3GPP Anchor SGi Home EPC Op . IP Serv (IMS, PSS, etc.) Visited EPC S2 S2 WLAN non 3GPP * Color coding: red indicates new functional element / interface GSM 1800 GSM 1900 GSM 900 GSM ph.1 GPRS R97 3G EDGE R98 R99 Packet Cable HSPA WLAN Fixed Rel-5/6 Rel-6/7 WiMAX? E-UTRAN ? Rel-8 and onwards ...and let’s make it IP all the way to the terminal ! 3 SIM / USIM / ISIM support GSM Ph.2 – R98 R99 – Rel-4 Rel-5 – Rel-7 Rel-8 -> ??? GSM phone UMTS 3G phone IP Multimedia SAE GSM phase 2 Mandatory SIM No USIM support Optional GPRS (R97 ->) WCDMA or EDGE Mandatory SIM USIM support is: Mandatory for WCDMA Optional for GSM/EDGE IMS Mandatory USIM No SIM specs Optional support of legacy SIM ISIM support mandatory for IMS ME WLAN (Rel-6) SAE USIM mandatory for SAE access 3G AKA security SIM access not allowed any more No need to update legacy USIM IMC as alternative to ISIM for non3GPP access 4 Security evolution Phase 2 SIM SIM 2G AKA UICC Smartcard, R99 -> SIM Appl 2G AKA RAND GSM security SRES Kc SIM application in UICC SIM security in USIM USIM Application 2G AKA 3G AKA RAND+ AUTN RANDRAND +AUTN RAND SRES Kc 3G AKA ISIM Appl SRES Kc RES Ck Ik RES Ck Ik IMS 3G AKA in ISIM 3G AKA in UICC Authentication Request (RAND , AUTN SIP 401 ) Unauthorise d 5 System Architecture Evolution (SAE) • LTE = E-UTRAN = evolved radio network – Megabit class data rates – Short delays – Short transition from idle to active • SAE = System Architecture evolution – Evolved IP oriented multi access architecture • • • • • • E-UTRAN integrates only to SAE, A/Gb or Iu not possible Strongly IP based PS only network SAE covers both 3GPP and non-3GPP access technologies Seamless roaming between E-UTRAN, 2G and 3G (tight interworking) Loose interworking with non-3GPP accesses Currently work is progressing on GTP for intra-3GPP mobility and IETF based mobility for non-3GPP mobility – The main Architecture specifications 23.401 and 23.402 frozen in June 2008 – Protocol work is ongoing with the goal to freeze it in December 2008 6 SAE/LTE Deployment • Deployments are expected to start with overlapping cellular coverage – E-UTRAN overlapping with legacy 3GPP GERAN / UTRAN coverage – E-UTRAN overlapping with legacy 3GPP2 coverage – Multi-mode networks and terminals • E-UTRAN is a packet-only radio with no CS capacity • Initially E-UTRAN is foreseen as “islands” in the sea of legacy cellular access – – – – Mobility between E-UTRAN and legacy access is required Mobility between PS and CS domains is required Multi-mode terminals expect to use PS coverage where available Desire to keep the connectivity and services 7 IP Multimedia Subsystem (IMS) • • PS domain IP Multimedia service platform Based on open IETF standards – End to end IP (SIP) – Multi access Internet • GPRS, I-WLAN, fixed xDSL, Packet Cable defined • More access technologies to follow... Find & route to destination PSTN IP Multimedia Core Circuit-switched network (2G or 3G) IP connectivity (GPRS, 3G,...) User data Any IP connectivity (3G, WLAN,...) End-to-End IP services 8 Common IMS • 3GPP members, 3GPP2, WiMAX forum, ETSI TISPAN and CableLabs contribute to 3GPP common IMS specifications – Different requirements are supported in common implementation • All IMS specifications are harmonized to 3GPP specifications – Common parts are defined in 3GPP specifications only • Core IMS entities (CSCFs, AS, UE IMS client,...) + agreed common functions – Other organisations either reference or re-use 3GPP specification as it stands – Any changes or additions in the Common IMS area are made in 3GPP • All 3GPP members can contribute on their favourite work items • Ongoing work initiated by 3GPP members, CableLabs, 3GPP2 and ETSI TISPAN – The scope and coverage of Common IMS have been agreed by the SDOs • Common version of IMS specifications in Rel-8 – Business or architecture specific additions to 3GPP Common IMS are possible outside the agreed Common IMS area 9 Multi-mode, Service continuity • Call control protocols – E-UTRAN is a PS only radio, speech and other services are IMS based – PS domain IMS uses SIP protocol for call control (3GPP TS 24.229) – CS domain uses Call Control defined in 3GPP TS 24.008 • Voice Call Continuity – Domain transfer of ongoing call – Typically from E-UTRAN to 2G or 3G access • CS fallback – Paging the mobile in E-UTRAN to start CS service in 2G or 3G access – Not an E-UTRAN service, but fallback to existing service via 2G/3G • IMS service continuity – IMS service between E-UTRAN and other PS only, such as WLAN • IMS Centralized Service Control (ICS) – Common telephony services between CS and PS domain 10 Multi-mode, IMS registration in Rel-7 • When S-CSCF detects that the same UE registers again, it considers this as an update and overwrites existing registration • In some cases it may not be possible to de-register when changing from one access technology to another – UE might lose radio coverage before being able to de-register • S-CSCF detects that the registration is from the same UE based on the same privateID, which is practically a device-ID UE (privateID-A) REGISTER 1 (privateID-A, IPaddress: 1.2.3.4) S-CSCF UE registered with 1.2.3.4 loss of radio REGISTER 2 (privateID-A, IPaddress: a.b.c.d) UE registered ONLY with a.b.c.d – REGISTER 1 got overwritten with REGISTER 2 11 Multi-mode, IMS Multiple registration, Rel-8 • A UE is able to register the same public user identity with multiple IP addresses at the same time • Used e.g. for IMS Service Continuity (e.g. handing over from I-WLAN to GPRS) • No gap in reachability of the mobile HSS GPRS IP: 1.2.3.4 P-CSCF 1 S-CSCF I-WLAN IP: a.b.c.d P-CSCF 2 user1 / 1.2.3.4 / UE-A user1 / a.b.c.d / UE-A UE-A 12 Multi-mode, Single Radio Voice Call Continuity Transfer from E-UTRAN to GERAN with active call (not all entities shown) IMS MME E-UTRAN HO command HO required measurements relocation request relocation response session transfer PLMN serving remote user MSC server prepare HO HO complete 2G or 3G MSC 13 Multi-mode, CS fallback Directing the UE from E-UTRAN to 2G/3G for CS service MME E-UTRAN paging SETUP paging PLMN serving remote user call setup SETUP paging resp. 2G or 3G MSC 14 Multi-mode, Network selection • Network selection comprises two parts – Network operator selection (the goal, based on commercial agreement) • Home operator determines which visited operators are preferred – Access technology selection (the means, based on technical criteria) • Serving visited operator determines access technology, frequency band and cell • Multi-mode phones supporting many access technologies are a new challenge • Network selection within each technology is defined for 3GPP and non-3GPP accesses • The combination of multiple technologies is undefined • Two approaches are foreseen in Rel-8 – 3GPP network selection procedures are extended to cover any non-3GPP system that supports ITU-T defined concepts of MCC and MNC – For others the ANDSF can (optionally) download network selection policy • Access technology preference, policy for changing access technology, etc. • MCC = Mobile Country Code • MNC = Mobile Network Code • ANDSF = Access Network Discovery and Selection Function 15 Multi-mode network selection, Outbound roaming example • • HPLMN is not available Prioritized VPLMNs are listed with no associated RAT in PLMN selector with access technology: – – – • VPLMN2 is selected via 2G, 3G or E-UTRAN – • VPLMN5 is not available VPLMN1 is available VPLMN2 is available – PLMN Selector (USIM): Cell & RAT may change within the selected PLMN Background scan for higher priority network HPLMN VPLMN1 CDMA VPLMN5 VPLMN2 VPLMN1 VPLMN1 USIM configured RAT preference possible After PLMN selection normal idle mode is resumed – HPLMN has not configured RAT priority for this VPLMN VPLMN1 E-UTRAN ? VPLMN2 UTRAN VPLMN2 GERAN VPLMN2 E-UTRAN RAT = Radio Access Technology, PLMN = Public Land Mobile Network VPLMN2 16 Thanks for your attention ! More information at www.3gpp.org 17 Architecture Annex: 3GPP and non-3GPP access architecture 18 SAE architecture (23.401) HSS NAS signaling+sign. security PCRF Mobility between 3GPP ANs Idle mode UE reachability P-GW and S-GW selection S 7 S6a PDN Gateway SGSN selection at HO Authentication Bearer establishment HPLMN VPLMN UTRAN Charging support S12 S3 Legal interception MME Signaling security (UMTS AKA) S4 Mobility anchor S11 Packet routing S10 Serving Gateway E-UTRAN S1-U User plane security (UMTS AKA) Services (e.g. IMS, PSS etc.) Policy enforcement GERAN UE •Operator’s IP Packet screening & filtering SGSN “LTE -Uu ” SGi UE IP address allocation S8 S1-MME Rx + Idle mode packet buffering & DL initiation Legal interception 19 SAE non-3GPP access (23.402) HSS Wx* S6a S4 2G/3G SGSN PCRF S3 Rx+ S7 S2 for connectivity via non3GPP acces MME Rx+ S11 SGi S1-MME Operator’s IP Services S10 Serving Gateway EUTRAN Untrusted IP access via ePDG (e.g. IMS, PSS etc.) PDN Gateway S5 S6c S1-U S2b Trusted IP access directly to P-GW Wm* ePDG S2c 3GPP AAA S2a Server Wn* HPLMN Non-3GPP Networks Trusrted* Trusted Non-3GPP IP Access Non-3GPP IP Access or 3GPP Access Wu* UE Untrusted Non-3GPP IP Access UE Wa* Ta* * Untrusted non-3GPP access requires ePDG in the data path 20