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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 supportGSM Ph.2 – R98 R99 – Rel-4 Rel-5 – Rel-7 Rel-8 ->

GSM phone UMTS 3G phone IP Multimedia SAE

GSM phase 2Mandatory SIMNo USIM supportOptional GPRS (R97 ->)

WCDMA or EDGEMandatory SIMUSIM support is:

Mandatory for WCDMAOptional for GSM/EDGE

IMSMandatory USIMNo SIM specsOptional support of legacy SIMISIM support mandatory for IMS MEWLAN (Rel-6)

SAEUSIM mandatory for SAE access3G AKA securitySIM access not allowed any moreNo need to update legacy USIMIMC as alternative to ISIM for non-3GPP access

???

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Security evolutionPhase 2 SIM

2GAKA

SIM

SRESKc

RAND

RESCkIk

RESCkIk

USIM Application3GAKA

ISIM ApplUICC 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-CSCFP-CSCF 1

P-CSCF 2

GPRSIP: 1.2.3.4

UE-A

HSS

I-WLANIP: 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):

VPLMN5VPLMN2VPLMN1

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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Thanks for your attention !

More information at www.3gpp.org

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Architecture Annex:3GPP and non-3GPP access architecture

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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 anchorPacket routing

Idle mode packet buffering & DL

initiationLegal interception

UE IP address allocationPacket screening &

filteringPolicy enforcementCharging supportLegal interception

NAS signaling+sign. security

Mobility between 3GPP ANsIdle mode UE reachabilityP-GW and S-GW selection

SGSN selection at HOAuthentication

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*

UntrustedNon-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

MME S11

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)