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3GPP TSG CT Chairman3GPP TSG CT Chairman Hannu HietalahtiHannu Hietalahti
3GPP presentationArchitecture evolutionMoscow, October 2008
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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
Contents
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Continuous improvement of access technologiesProvision of services over any access network
...and let’s make it IP all the way to the terminal !
Common Core network
GSM 900
3G HSPA
WLAN E-UTRANEDGE
GSM 1800
GPRS
GSM 1900
GSM ph.1 R97 R98 R99 Rel-5/6 Rel-6/7 Rel-8 and onwards
WiMAX?
?
Evolved RA N S 1
GERAN
UTRAN
GPRS Core G b
I u
S 3
S 8
S 2
S7 Rx +
Home EPC MME UP E
S 6
Op . IP Serv (IMS, PSS, etc.)
Home Inter AS Anchor
HSS S 6
non 3GPP WLAN
S4
S 2
vPCRF
S 7
hPCR F
Visited Network
Home Network
S 9
Visited EPC
Evolved RA N S 1 SGi
UTRAN I u
S 3
S 8
S 2
Rx +
Home EPC MME UP E
S 6
Op . IP Serv (IMS, PSS, etc.)
Home Inter AS Anchor
HSS S 6
non 3GPP WLAN
S 2
vPCRF
S 7
hPCR F
Visited Network
Home Network
S 9
* Color coding: red indicates new functional element / interface
3GPP Anchor
SGSN
S5a
From GSM to multi-access
Fixed
PacketCable
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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 non-3GPP access
???
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Security evolution
Phase 2 SIM
2GAKA
SIM
SRESKc
RAND
RESCkIk
RESCkIk
USIM Application
3GAKA
ISIM Appl
UICC Smartcard, R99 ->
2GAKA
RANDRAND
SRESKc
2GAKA
SIM Appl
SRESKc
RAND
3GAKA
Authentication Request (RAND )SIP 401 Unauthorised
, AUTN
GSM security
SIM application in UICC
3G AKA in UICC
IMS 3G AKA in ISIM
+AUTN
SIM security in USIM
RAND+AUTN
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• 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
System Architecture Evolution (SAE)
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• 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
SAE/LTE Deployment
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Internet
IP Multimedia Subsystem (IMS)• PS domain IP Multimedia service platform
• Based on open IETF standards– End to end IP (SIP)– Multi access
• GPRS, I-WLAN, fixed xDSL, Packet Cable defined
• More access technologies to follow...
Circuit-switched network
(2G or 3G)IP
MultimediaCore
PSTN
IP connectivity
(GPRS, 3G,...)
Find & route to destination
User data
Any IP connectivity (3G, WLAN,...)
End-to-End IP services
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• 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
Common IMS
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• 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
Multi-mode,Service continuity
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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) S-CSCF
REGISTER 1 (privateID-A, IPaddress: 1.2.3.4)
loss of radio
UE registered with 1.2.3.4
REGISTER 2 (privateID-A, IPaddress: a.b.c.d)UE registered ONLY with a.b.c.d – REGISTER 1 got overwritten with REGISTER 2
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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
S-CSCF
P-CSCF 1
P-CSCF 2
GPRS
IP: 1.2.3.4
UE-A
HSS
I-WLAN
IP: a.b.c.d user1 / 1.2.3.4 / UE-A
user1 / a.b.c.d / UE-A
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Multi-mode,Single Radio Voice Call ContinuityTransfer from E-UTRAN to GERAN with active call (not all entities shown)
PLMN serving
remote user
MSC server
IMS
MSC
E-UTRAN
2G or 3G
measurements
HO required
MME
relocationrequest
prepare HO
relocationresponse
sessiontransfer
HO command
HO complete
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Multi-mode, CS fallbackDirecting the UE from E-UTRAN to 2G/3G for CS service
PLMN serving
remote user
MSC
E-UTRAN
2G or 3G
MME
SETUP
call setup
paging
paging
paging resp.SETUP
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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
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PLMN Selector(USIM):
VPLMN5
VPLMN2
VPLMN1
Multi-mode network selection,Outbound roaming example
HPLMN
VPLMN1
VPLMN2
VPLMN1CDMA
VPLMN2GERAN
VPLMN1E-UTRAN
?
HPLMN has not
configured RAT priority
for this VPLMN
• HPLMN is not available• Prioritized VPLMNs are
listed with no associated RAT in PLMN selector with access technology:– VPLMN5 is not
available– VPLMN1 is available– VPLMN2 is available
• VPLMN2 is selected via 2G, 3G or E-UTRAN– USIM configured RAT
preference possible• After PLMN selection
normal idle mode is resumed– Cell & RAT may change
within the selected PLMN
– Background scan for higher priority network
RAT = Radio Access Technology, PLMN = Public Land Mobile Network
VPLMN2UTRAN
VPLMN2E-UTRAN
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S6a
HSS
S8
S3 S1-MME
S10
UTRAN
GERAN SGSN
MME
S11 Serving Gateway UE
“ LTE - Uu ” E-UTRAN
S12
HPLMN
VPLMN
PCRF S7 Rx
+ SGi •Operator’s IP
Services (e.g. IMS, PSS
etc.)
PDN Gateway
S1-U
S4
Mobility anchor
Packet routing
Idle mode packet buffering & DL
initiation
Legal interception
UE IP address allocation
Packet screening & filtering
Policy enforcement
Charging support
Legal interception
NAS signaling+sign. security
Mobility between 3GPP ANs
Idle mode UE reachability
P-GW and S-GW selection
SGSN selection at HO
Authentication
Bearer establishment
SAE architecture (23.401)
User planesecurity(UMTS AKA)
Signalingsecurity(UMTS AKA)
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Trusrted*
Non-3GPP IP Access
or 3GPP Access
SGi
PCRF
S7
S6a
HSS
ePDG
S2b
Serving Gateway
Wn*
3GPP AAA
Server
Operator’s IP Services
(e.g. IMS, PSS etc.)
Wm*
Wx*
Untrusted
Non-3GPP IP Access
Trusted
Non-3GPP IP Access
Wa*
Ta*
HPLMN
Non-3GPP Networks
S1-U
S1-MME
EUTRAN
2G/3G SGSN
S4
S3
S5S6c
Rx+
Rx+
S2a
PDN Gateway
MMES11
S10
UE
S2c
* Untrusted non-3GPP access requires ePDG in the data path
UE
Wu*
S2 for connectivity via non-
3GPP acces
Trusted IP access
directly to P-GW
Untrusted IP access via
ePDG
SAE non-3GPP access (23.402)
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