1. Policy and Regulatory Requirements for Future Mobile Networks
June 22nd 2005
F. COURAU
M. OLSSON

2. Introduction Policy and Regulation Network Sharing
IP Multimedia System IMS

3. Network Sharing NETWORK SHARING:
Regulation to impose sharing of part of the network elements between two or more operators on a regional basis

4. Network sharing in Release 99, 4 and 5
CN PLMN2
CN PLMN1
CN PLMN3
One Radio per PLMN

5. Network sharing in Release 6
CN PLMN2
CN PLMN1
CN PLMN3
Different PLMNS on a single radio

6. IP Multimedia System

7. IP support in Mobile Network
A bit of history
Support of IP services was first introduced in GSM networks in Release 97 of the specifications as complement to the Circuit Switched Services
The packet services was introduced in such a way that it did not destabilize the provision of Circuit Switched services and it also minimized the impact on the Radio part.
The specifications defines a mobile specific architecture taking the roaming and the mobility aspects into account and offering a differentiated Quality of Service
When defining the third generation systems (Release 99) the support of packet services was fully integrated in the architecture
Release 99 for both GSM and UMTS introduced the notion of Quality of Service (Background, Real time, Interactive)

8. GPRS Architecture Overview
ISDN
MSC/VLR
BSS
with PCU
HLR
SGSN
GGSN
GPRS Mobile
Frame
Relay
GPRS
Backbone
Internet
X.25
DNS
DHCP

9. General Architecture Overview
Circuit Switched
Domain
Packet Switched
IP Multimedia
Subystem
Other Accesses
(e.g.WiFi
CDMA2000)
Network
UTRAN
BSS/GERAN
IP Network
PSTN / CS PLMN

10. Main IMS Features A Multi-phase Standardisation
IMS Phase 1 - 3GPP Rel5
SIP Session Control for IMS Signalling
Security & IMS Authentication :
SIP signalling integrity (IPSec : UE / P-CSCF)
IMS User/Service authentication (IMS-AKA)
QoS :
SBLP (Go : P-CSCF-PDF / GGSN-PEF)
SIP Compression (Sigcomp, UE/P-CSCF)
Header compression in RAN (UE / RNC, re-use of RoHC)
Charging (mainly Offline) and OAM&P
Multimedia codecs
OSA support
CAMEL (Phase 4) for IM-SSF
IPv6 use for SIP signalling and IMS user traffic
IPv4 optional (guidelines & IPv6 evolution)
IMS Phase 2 - 3GPP Rel6
Inter-working with non-IMS IP networks (e.g. Internet)
Inter-working with CS networks (e.g. PSTN, CS PLMN)
IMS Services combining CS (rt) & PS (nrt) : CSI Phase 1
Access agnostic IMS specifications
UTRAN QoS optimisation for PS conversational services
WLAN/3GPP inter-working for using PS/IMS services
Presence/Instant Messaging (SIMPLE)  OMA
Group management & Conferencing (SIP)
Immediate and Session based messaging
Service enablers for IMS : PoC  OMA
Dynamic QoS policy (including Gq (P-CSCF/PDF))
Lawful interception
SIP forking
Full charging framework (incl. Online and Flow based)
IPv4 option & IPv6 evolution guidelines still applicable
Emergency services
IMS local services
Enhanced QoS (extension for IP Inter-working)
MRFP / MRFC (Mp) & ALG/Tr-GW (Ix) interfaces
GERAN optimisation for PS conversational services
IMS ‘Phase 3’ - 3GPP Rel7 (Draft contents, depends on Rel6 and company proposals)
IMS enhancements for Fixed Broadband access
Interim Security (IP based authentication)
Merging of Go and Gx (TPF/FBC) interfaces

11. I M S IP Multimedia Subsystem
Primarily designed (3gpp R5) to work on top of GPRS using SIP signalling
But extended (3gpp R6) to work on top on non-GPRS based access and SIP TEs
(Harmonised with the 3GPP2 (CDMA 2000) IP Multimedia Domain (MMD))
On going work with ETSI TISPAN to adapt IMS for requirements of fixed networks
Services on top of IMS (e.g. MMS, PoC, IM/PM, DRM, DM are also
developed by other organizations like OMA.
Circuit Switched
Domain
Packet Switched
IP Multimedia
Subystem
Other Accesses
(e.g.WiFi
CDMA2000)
Network
UTRAN
BSS/GERAN
IP Network
PSTN / CS PLMN

12. 3GPP IMS Architectural Overview
Application
(Ext. SIP AS, OSA AS, CAMEL SE)
HSS
OSA SCS
IM SSF
SIP AS AS
IMS Data Handling
SLF
HLR/AuC (‘CS/PS’)
CSCF
BGCF
S-CSCF
I-CSCF
MGCF
P-CSCF
MRF
SGW
‘IMS IPGW
MRFC
PDF
ALG
CS Networks
(PSTN, CS PLMN)
MRFP
TrGW
IMS-MGW
IPv4 PDN
(IPv4 Network)
IP CAN
PEF/TPF
IPv4/IPv6 BB
IMS
Terminal
ABG TE AN BG
IPv6 PDN
(IPv6 Network)

13. Main IMS principles 2 phase registration,UE
GPRS
IMS
1. Bearer Level Registration: e.g.GPRS Attach
(2. Establishing signaling link e.g. PDP Context Activation)
3. CSCF Discovery
4. Application (IMS) Level Registration
specific (QoS, charging, security,) at Access and at IMS case

14. IMS in PLMNs & Roaming Two possible Cases Proxy CSCF
P-CSCF / PDF are located in
the same network as GGSN
Two possible Cases
The S-CSCF is always located
in the Home Network
Home Network
Visited Network
IM Subsystem
Inter -
Network
IP Backbone
Internet
Intranets UE
GGSN BG
SGSN
PDP Context Gi
Virtual presence of UE
in visited network IM subsystem (
UE’s IP
address is here)
Proxy CSCF
in Visited Network
P-CSCF
S-CSCF / AS
This case is possible too
IM CN SUBSYSTEM
Service Network
P-CSCF
S-CSCF / AS Gi
GGSN
PDP Context UE
SGSN
Access network connecting the user
Proxy CSCF
in Home Network
This is in fact the GPRS
roaming case

15. IMS Communication Focus Example with two Roaming IMS Mobile Users
Serving Network A
Serving Network B
Access Network A
Service
Platform A
Service
Platform B
Access Network B
(AS )
(AS ) A B P-
CSCF
SIP / SDP
SIP / SDP
SIP / SDP P-
CSCF C D S
-CSCF S
-CSCF
PDF A B
PDF Gm Gm
SIP /
SDP Go Go
SIP /
SDP
inviting
SGSN
GGSN
Data-
Path
GGSN
SGSN IP
Backbone Network
UEA
UEB
PDP
Context
PDP
Context
Session
level
(SIP/SDP
signalling )
Bearer level
(PDP
context
activation / modification /
Release)
Interaction
between
session and
bearer level
(COPS)
I-CSCF (between P-CSCF and S-CSCF) not shown for simplicity

16. IMS charging and QoS: interface between service and access network
Subscription database
Three types of charging
On line charging
Off line charging
Flow based charging
Pre-paid
IP Multimedia
Subystem
P-CSCF
Policy and charging Relay
Gq,Rx
Access GW (GGSN)
Packet Switched Domain (Access)
Go,Gx

17. Emergency & LI Overview
ADMF = LI administration
DF = Delivery Function (to LEA= Law Enforcement Agency)
For the target IMS only service, Emergency calls via IMS to be deployed (3GPP R7)
But absence of deployment of an IMS emergency infrastructure does not block deployment of IMS conversational service provided that
UE or Network can detect emergency requests and direct them via CS domain
A call back from Emergency Center is always directed to UE via CS domain
LI infrastructure in PLMN (ADMF, DF) to be upgraded to take into account IMS and to inter-operate with CSCF. For 3gpp,
IMS specific interception deals only with signaling plane interception.
User plane interception is to be carried out at Access level (GPRS)
Note that user plane generally goes directly from UE to UE without being handled by any MGW (only IW with CS networks) in the network

18. LI for 3GPP IP/IMS : Simplified Overview of Functional ArchitectureX1
HI1
IMC
MM Call
Server
P-CSCF/
S-CSCF
ADMF
Radio
Network
LEMF
IMS Domain Gi
X1_2/3p
3GPP Interfaces
Iu/Gb Gn X2 IP
HI2
Backbone Gi
RAN
SGSN
GGSN*
Mobile
LI target
Internet
LIG
IP-
HI3
Signalling (incl.SIP) X3
DF2/ DF3
User Plane
Management
* Interception at GGSN is optional
Interception of signalling is called “IRI” = Intercept Related Information

19. Annex: A few abbreviations explained
Definitions
GPRS
GGSN Gateway GPRS Support Node
SGSN Serving GPRS Support Node
IMS
API Application Program Interface
AS Application Server
BCSM Basic Call State Model
BG Border Gateway
BGCF Breakout Gateway Control Function
CSCF Call Session Control Function
MGCF Media Gateway Control Function
MGF Media Gateway Function
P-CSCF Proxy‑CSCF
S-CSCF Serving‑CSCF

20. Thank You for Your Attention Alcatel Mobile Solutions
&
Alcatel Mobile Solutions