01 WCDMA Core Network Overview ISSUE1.0

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WCDMA Core Network

Overview

ISSUE 1.0


Chapter1 Core Network Evolution

Chapter2 R99 Core Network




Definition of Core Network CN includes a series of physical entities to realize user location

management, network function and service control, such as (G)MSC, HLR,

SCP, SMC,GSN etc.

CN can be divided into three types: Home Network Domain, Transit Network

Domain and Transit Network Domain. Ref. is 3GPP 23.101.

User Equipment Domain

Access Network Domain Core Network Domain

Infrastructure Domain

Cu

Mobile

Equipment

Domain

USIM

Domain

Home

Network

Domain

Transit

Network

Domain

Uu Iu

[ Zu]

[ Yu]

Serving

Network Domain


Release Evolution of WCDMA

R4

R5

R99

Inherit all the services and

functions of 2G ( GSM

and GPRS )

CN is composed of CS

domain and PS domain

Adopt WCDMA UTRAN

Iu interface between RAN

and CN is based on ATM

Inherit all the services and

functions of R99

CS domain change: control is

separated from bearer, the

function of MSC can be fulfilled

by MSC SERVER and MGW.

Packet voice supported by CS

domain, supporting ATM, IP,

TDM bearer

Inherit all the services

and functions of R4

IM domain is adopted

RAN evolved to IP

Enhanced IP QoS ability ,

supporting end to end IP

multimedia service

2000 2001 2002 function frozen time


Questions

What functions can CN provide?

What is the WCDMA first version? How about the features?

Which domain in WCDMA R4 can implement the function of

control separated from bearer?


R99 Network Architecture

BSS

BSC

RNS

RNC

CN

Node B Node B

A IuPS

Iur

Iub

MS

Uu

MSC SGSN

Gs

GGSN GMSC

Gn HLR

Gr

Gc C

D

E

AuC

H

EIR

F Gf

Gi PSTN

IuCS Gb

VLR

B

Gp

VLR

G

BTS BTS

Um

RNC

Abis

MSC

B

PSTN

cell

PCU

UE



GSM /GPRS BSS

BTS

BSC

NodeB

RNC

PCU

UTRAN

SCP

SMS

SCE

PSTN

ISDN

Internet,

Intranet

MSC/VLR GMSC

HLR/AUC

SGSN

CG BG

GGSN

GPRS骨干网/

Other PLMN

SS7


R99 Core Network－Features and Technologies

Core Network is split into CS domain and PS domain. CS domain

is based on original GSM network. PS domain is based on

original GPRS network.

CS domain: used to provide Circuit-switched service. Network

mode can support TDM, ATM and IP. Physical entities include

switching equipment (such as MSC/VLR, GMSCs), and inter-

working equipment (IWF).

PS domain: used to provide Packet-switched service. Network

mode is IP. Physical entities include SGSN, GGSN, CG , BG etc.


R99 Core network－Function Entity(1)

Function entity shared by CS domain and PS :

HLR: to realize mobile subscriber management and

location information management ;

VLR: to deal with all kinds of data information of current

mobile subscriber ;

AUC: to store authentication information of mobile

subscriber ;

EIR: to store IMEI data of mobile subscriber;

SMS: Short Message Center.


R99 Core network－Function Entity(2)

Function entity of CS domain:

MSC: to realize switching and signaling control function of

circuit service.

GMSC: to realize addressing function for different network.

GMSC and MSC can be integrated together or separated

independently.

IWF: integrated together with MSC, to realize inter-working

with PLMN and ISDN, PSTN , PDN (Mainly complete

signaling transfer function), its functions can be defined

based on specified services and network types.


R99 Core Network－Function Entity(3)

Function entity of PS domain:

SGSN: to realize packet switching function, signaling

control function and route function of packet service.

GGSN: to realize inter-working with PS domain and

external data network.

CG: to realize billing function of packet service.

BG: to realize inter-working of two GPRS network and

guarantee the security of network.


R99 Core Network－Interface(1)

Interface between CN and RAN/BSS:

A Interface: to realize mobile station management, base station

management, mobility management and call processing, etc.

Gb interface: to realize packet data transmit and mobility

management.

Iu-CS interface: to realize RNS management, mobility

management and call control function.

Iu-PS interface: its basic function is similar to Iu-CS interface.



CS internal interface:

B interface (MSC-VLR): A private interface between VLR

and MSC. It is used for the MSC to query the current

location information of a Mobile Station (MS) from the Visit

Location Register (VLR), or request the VLR to update the

current location information of the MS or is used for the

operations of supplementary services.

C interface (MSC-HLR): to get MSRN, the IN service

related subscriber status and location information.



D interface (VLR-HLR): used to exchange the location

information of the MS and the subscriber management

information.

E interface ( between MSC): to be used for handover

process between two MSCs.

F interface (MSC-EIR) : to be used for EIR to verify IMEI

status information of mobile equipment.

G interface (between VLR): to exchange IMSI and

authentication information when MS moves from one VLR

to another VLR.


Questions

What’s the functions of R99 core network elements ?

Which interfaces do we have in the R99 core network ?



Section 1 Networking and Interface

Section 2 R4 Features


SCP

SMS-C

GMLC/SMLC HLR/EIR

CAP

MAP MAP

MAP

SIGTRAN

SS7

UTRAN

BSS TDM

MGW MGW

RTP(AAL2)/AMR

IP(ATM)

BackBone IP network

GSM/R99PLMN

PSTN/ISDN VMSC Server

RANAP

BSSAP

AAL2

H.248

MAP

BICC GMSC Server

TDM/G.711

TDM/G.711



R4 Core Network－Function Entities

MSC Server: control layer, to realize MM (mobility

management), CM ( call control), MGC (media gate control) .

MGW：bearer layer, to realize the exchange of voice and

media flow, and provide all kinds sources, such as TC, EC,

play announcement and receive DTMF.

SG: to realize signaling transfer from MTP (SS7 transmission

layer) to SCTP/IP (SIGTRAN transmission layer).


R4 Core Network－Interface and Protocol (1)

MGW

Mc Mc

Nb

Nc

MSC Server

MGW

GMSC Server

/ISUP/TUP

MTP3 MTP3B M3UA

MTP2 SSCF/SSCOP SCTP

MTP1 AAL5/ATM IP

H.248

SCTP UDP MTP3B

IP SSCF/SSCOP/AAL5

RTP AAL2 Voice

UDP/IP ATM PCM


R4 Core Network－Interface and Protocol (2)

Mc interface ((G)MSC Server–MGW) : H.248 is adopted, to

realize the flexible connection processing for multi call mode,

multi media；

Nc interface (MSC Server–(G)MSC Server) : to realize the

inter-office call control. It adopts BICC protocol ；

Nb interface ( Between MGWs)：to realize the transfer of

control and user information (voice, data, picture, media) in

bearer layer，and realize the transfer of different media frame

format. RTP/UDP/IP and AAL2/ATM protocol is adopted.



Section 1 Networking and Interface

Section 2 R4 Features


Bearer and Control Separated

Control

Layer

Bearer

Layer

MSC

H.248


Four-layer Architecture

Service Management

Network Control

Core Switching

Edge Access

SoftSwitch

3G Access AMG

IAD

Broadband Access

PSTN

TMG SG

PLMN

Packet Core Network

UMG

UMG

App Server Policy Server iOSS IN

SoftSwitch

MRS

SS RR


Embedded SG－Save transmission link

SCP

SMS-C

GMLC/SMLC HLR/EIR

CAP

MAP MAP

MAP

SS7 network

UTRAN

BSS TDM

MGW MGW

RTP(AAL2)/AMR

IP(ATM)

BackBone IP

GSM/R99PLMN

PSTN VMSC Server

RANAP

BSSAP

AAL2

H.248

MAP

BICC GMSC Server

TDM/G.711

TDM/G.711

SG7000


Centralized Service Control

New Service

Server

MGW

MGW MGW MGW MGW

MGW

MGW

Next Generation Network

Service is not combined with MGW.

Service upgrade only relates to server layer.

Centralized service management, easy to upgrade.

Traditional Network

Service is combined with MSC.

Most of services need to upgrade all MSCs.

MSCs locates dispersedly, difficult to upgrade.


Distributed Architecture－Flexible networking

Traditional network

Inter-working mode.

The advantage of distributed networking：

Traffic route is the best, network performance is the best.

Mostly suitable for the operators with wide coverage.

Distributed network

inter-working mode.


Questions

What’s the advantage of embedded SG ?

What’s the advantage of R4 core network ?



Section 1 R5 Networking

Section 2 SIP Introduction


GSM /GPRS BSS

BTS

BSC

NodeB

RNC

PCU

UTRAN

SCP SMS

SCE

PSTN/PLMN

Internet,

Intranet

HLR/AUC/HSS

SGSN

CG BG

GGSN

GPRS

backbone

MGW MGW

VMSC Server GMSC Server

IP/ATM Backbone CS domain

PS

domain

Iu-CS

Iu-PS

IP backbone

MRFP

IMS domain

MGW

P-CSCF S-CSCF

MGCF

MRFC

SS7



R5 Features

3GPP R5 Features:

Inherit all the WCDMA R4 service and functions.

IMS ( IP Multimedia System) is added based on PS, CS of R5 is

consistent with that of R4.

Iu interface can select IP and ATM. IP based is a trend of networking.

IP QoS is enhanced.

Services are enhanced, such as OSA，Push Service

R5 realizes ALL IP network put forward by 3GPP.

IP will become the bearing technology for all signaling message and

change the original call flow.


R5 Core Network－IMS (1)

IMS main function entity:

CSCF：

P-CSCF

S-CSCF

I-CSCF

HSS

SLF

BGCF

MGCF/IM MGW

MRFC/MRFP

AS

PDF/PEF

P - CSCF

CSCF MGCF HSS

Cx

IP Multimedia Networks

IMS - MGW

PSTN

Mn

Mb

Mg

Mm

MRFP

Mb

Mr

Mb

Legacy mobile signalling Networks

CSCF

Mw

Mw

Gm

BGCF Mj Mi

BGCF

Mk Mk

C, D, Gc, Gr

UE

Mb

Mb

Mb

MRFC

SL F Dx

M p

PSTN

PSTN

Gq

UE

Gn Iu - PS

PDF

Go

GGSN SGSN

Gi

UTRAN

MSC Iu - CS

PS

IMS

CS

WLAN or IP-CAN -



CSCF：Call Session Control Function

Is divided into P/S/I three types based on its function and location.

P-CSCF(Proxy CSCF)：It is the first connection point for subscriber in IMS and

provide Proxy function. It can receive service request and transfer them, but can

not modify the Request URI field in INVITE message; P-CSCF also can provide

user agent function (UA), it can interrupt and independently produce SIP

conversion at abnormal case.

S-CSCF(Serving CSCF)：S-CSCF is the core control of IMS, it is responsible for

UE to register, authenticate and conservation control, realize conservation route

function for calling and called IMS user. According to subscriber signed IMS

triggered rule, it can trigger the value added service route to AS and control service

negotiation.

I-CSCF(Interrogating CSCF): similar as IMS gateway node, provide node

distribution, route query and IMS Topology Hiding Inter-network function.



HSS:The Home Subscriber Server.

HSS stores the IMS subscriber signed information, including basic identity,

route information and service signed info. Centralized database, located at

the top of IMS core network. It stores the following information:

− IMS subscriber identity (including public and private identity), number

and address information.

− IMS subscriber security context: ciphering information for subscriber to

access network for authentication, roaming restrict information.

− IMS subscriber route information: HSS supported route information,

registration information and location information.

− IMS subscriber service signed information: including other AS value

added service data.



Section 1 R5 Networking

Section 2 SIP Introduction


SIP Development

SIP（Session Initiation Protocol）:

It is application layer control protocol, used to setup, modify, and terminate

multimedia session (including meeting). For example, internet telephone call.

− Originally derived from MBone experiment in 1996.

− In 1999, It was adopted as RFC2543 standard by IETF-MMUSIC work

group.

− In 1999, SIP work group was established independently, later, two work

group named as SIPPING and SIMPLE was newly set up, which is

mainly devoted to SIP.

− In the July of 2002, it is turned to the new standard RFC3261.

− Most of the content was re-written. It is more clear and precise and

some new features were added.

− Most of contents keep the backward compliance with RFC2543.


SIP Features

Based on text code.

Only concern about setup, modify and terminate the conservation. SIP-

URL is uesd to indicate the resources or subscribers needed to be

visited.

Flexible extended and powerful negotiation mechanism: Supported,

Unsupported, Require, ProxyRequire, Allow, Accept...

Simple networking provides the flexibility, reliability and expandability.

Relay equipment (Proxy and Redirecter) need not to care about the

message content, just transfer transparently.


Questions

What is the difference between R5 and R4?

What’s the network element of IMS?


Summary

This course mainly introduces the R99,

R4, R5 evolution and each features.

The emphasis is R4 network.

Summary

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01 WCDMA Core Network Overview ISSUE1.0

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