3gpp architecture evolution

1. 1
3GPP TSG CT Chairman3GPP TSG CT Chairman
Hannu HietalahtiHannu Hietalahti
3GPP presentation
Architecture evolution
Moscow, October 2008

2. 2
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

3. 3
Continuous improvement of access technologies
Provision 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 RAN
S1
GERAN
UTRAN
GPRS Core
Gb
Iu
S 3
S8
S 2
S7 Rx+
Home EPC
MME
UPE
S6
Op. IP
Serv
(IMS,
PSS,
etc.)
Home
Inter AS
Anchor
HSS
S6
non 3GPP WLAN
S4
S 2
vPCRF
S7
hPCRF
Visited
Network
Home
Network
S9
Visited EPC
Evolved RAN
S1 SGi
UTRAN
Iu
S 3
S8
S 2
Rx+
Home EPC
MME
UPE
S6
Op. IP
Serv
(IMS,
PSS,
etc.)
Home
Inter AS
Anchor
HSS
S6
non 3GPP WLAN
S 2
vPCRF
S7
hPCRF
Visited
Network
Home
Network
S9
* Color coding: red indicates new functional element / interface
3GPP
Anchor
SGSN
S5a
From GSM to multi-access
Fixed
Packet
Cable

4. 4
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
???

5. 5
Security evolution
Phase 2 SIM
2G
AKA
SIM
SRES
Kc
RAND
RES
Ck
Ik
RES
Ck
Ik
USIM Application
3G
AKA
ISIM Appl
UICC Smartcard, R99 ->
2G
AKA
RANDRAND
SRES
Kc
2G
AKA
SIM Appl
SRES
Kc
RAND
3G
AKA
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

6. 6
• 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)

7. 7
• 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

8. 8
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
Multimedi
a
Core
PSTN
IP
connectivity
GPRS,(
3G,...)
Find & route
to destination
User data
Any IP connectivity
(3G, WLAN,...)
End-to-End IP
services

9. 9
• 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

10. 10
• 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

11. 11
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
E (privateID-A) S-CSCF
REGISTER 1 (privateID-A, IPaddress: 1.2.3.4)
oss of
radio
UE registered with 1.2.3.4
REGISTER 2 (privateID-A, IPaddress: a.b.c.d)
UE registered ONLY wit
a.b.c.d REGISTER 1 got–
overwritten with REGISTE

12. 12
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-

13. 13
Multi-mode,
Single Radio Voice Call Continuity
Transfer 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
relocation
request
prepare HO
relocation
response
session
transfer
HO command
HO complete

14. 14
Multi-mode, CS fallback
Directing 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

15. 15
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

16. 16
PLMN
Selector
(USIM):
VPLMN5
VPLMN2
VPLMN1
Multi-mode network selection,
Outbound roaming example
HPLMN
VPLMN1
VPLMN
2
VPLMN1
CDMA
VPLMN2
GERAN
VPLMN1
E-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
VPLMN2
UTRAN
VPLMN2
E-UTRAN

17. 17
Thanks f or your
at t ent i on !
Mor e i nf or mat i on at
www. 3gpp. or g

18. 18
Ar chi t ect ur e Annex:
3GPP and non- 3GPP
access ar chi t ect ur e

19. 19
S6a
HSS
S8
S3
S1-MME
S10
UTRAN
GERAN
SGSN
MME
S11
Serving
GatewayUE
“LTE -Uu”
E-UTRAN
S12
HPLMN
VPLMN
PCRF
S
7
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 plane
security
(UMTS AKA)
Signaling
security
(UMTS AKA)

20. 20
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
S5
S6c
Rx+
Rx+
S2a
PDN
Gateway
MME
S11
S10
UE
S2c
* Untrusted non-3GPP access requires ePDG in the data path
UE
Wu*
S2 for
connectiv
ity via
non-3GPP
acces
Trusted IP
access
directly to
P-GW
Untruste
d IP
access via
ePDG
SAE non-3GPP access
(23.402)