UMTS NetworkArchitecture

UMTS ArchitectureSection Objectives

Upon completion of this section, the participant should be able to:

– List and Identify UMTS Elements in a PLMN including UTRAN and Core Network.

– Explain Briefly UMTS Standard Interface

UMTS ArchitectureGSM Architecture

D

C

BTS

BSCA bis

TCUA ter

MSC

VLR

HLR/AuC

BSSNSS PSTN

MS

UMTS ArchitectureFrom GSM to GSM/GPRS Architecture

D

C

BTS

BSCA bis

TCUA ter

MSC

VLR

HLR/AuC

PSTN

PCUGrFrame

RelayBackbone

SGSN GGSN

A

Gb

GbGn Gn

IPBackbone

MS

Access Network Core Network

PrivateIP

Backbone

UMTS ArchitectureUMTS Elements in a PLMN

Node B(BTS)

Uu

Iub (ATM)

RNCIu

(CS & PS)

RNC

Iur

Iur

Iu (CS & PS)

Node B(BTS)

Uu

TRAUMSC

VLR

SGSN

GGSN

Gn Gn

Gi

Iu CS

Iu PS

HLR/AuC

D

C

Gr

UE

UE

PSTN

ExternalPacket

Networks

ATMBackbone ATM

Backbone

Iub (ATM)

UMTS ArchitectureUTRAN Elements: Node B

• Node B– Logical node responsible

for radio transmission/receptionin one or more cells to/from the UE

– Performs and reports radio measurements to the RNC

– ATM Termination (Iub)

– Inner Loop Power Control

UMTS ArchitectureUTRAN Elements: RNC

• RNC– Responsible for the use and

integrity of the radio resourceswithin the RNS

– Responsible for the handoverdecisions that require signaling to the UE

– Provides a combining/splitting function to support macro diversity between different Node Bs

– ATM Switching and Multiplexing

UMTS ArchitectureCN Elements: GSM CN Elements (1)

• HLR (Home Location Register)– Stores the master copy of the user’s

service profile.– Stores the UE location.

• MSC/VLR (Mobile Switching Center/Visitor Location Register)– Performs all necessary functions in

order to handle the circuit switchedservices to and from the mobile stations

– Is expected to be identical in hardware to the latest generation GSM MSCs, although with a different software version

• GMSC (Gateway MSC)– The point where UMTS PLMN is

connected to external CS networks.

UMTS ArchitectureCN Elements: GSM CN Elements (2)

• SGSN (Serving GPRS Support Node)– Used for PS (Packet Switched) services.– Performs additionally the role of the VLR:

• Subscription Information– The IMSI– One or more temporary identities– Zero or more PDP addresses

• Location Information– Depending on the operating mode of the MS, the cell or the routing

areawhere the MS is registered– The VLR number of the associated VLR (if the Gs interface is

implemented)– The GGSN addressof each GGSN for which an active PDP context

exists

• GGSN (Gateway GPRS Support Node)– Gateway to external packet networks

UMTS ArchitectureOverall functions

Overall Functions of UTRAN

• Provision of Radio Coverage

• System Access Control

• Security and Privacy

• Handover

• Radio Resource Management and Control

Overall Functions of CN

• Switching

• Mobility Management

• Service Provision

• Transmission of User Traffic Between UTRAN(s) and/or Fixed Network

• Operations, Administration and Maintenance

UMTS ArchitectureUE Elements

UE RNCRNC CN

Node B provides :o Means of communication between UE and the networko Physical channels for synchronization, cell reselection…o Measurement information to the RNC

RNC is responsible for :o RRC (Radio Resource Control)o Handover (CS) & Cell Selection (PS)o Ciphering/ De-Ciphering

CN is responsible for :o Mobility Management (Location Registration, Authentication, Attach/Detach)o Session Management o Bearer Negotiation/Service Request

UMTS ArchitectureProtocols used over the Iub Interface

RNCRNC

IubNBAP

ALCAP

Iub FP

SAAL - UNI

AAL5

ATM

SAAL - UNI

AAL5

ATM

Data stream

AAL2

ATM

Control Plane User Plane

TransportNetworkControlPlane

The Node B Application Protocol (NBAP)provides the following functions :

Cell Configuration ManagementSystem Information ManagementResource Event ManagementCommon Transport Channel ManagementRadio Link ManagementMeasurements on Common ResourcesMeasurements on Dedicated Resources

Physical layer

Note : ALCAP is not used by Nortel

UMTS ArchitectureProtocols used over the Iur Interface

RNCRNC

IurRNSAP

ALCAP

Iur FP

SCCP

SAAL - NNI

AAL5

ATM

SAAL - NNI

AAL5

ATM

Data stream

AAL2

ATM

Control Plane User Plane

TransportNetworkControlPlane

The Radio Networks SubsystemApplication Protocol (RNSAP) providesthe following functions :

Radio Link ManagementMeasurement reporting functionTransfer of UL and DL functionsPower ControlLoad ManagementPaging functionsrelocation functions

Physical layer

RNCRNC

MTP3-B MTP3-B

Note : ALCAP is not used by Nortel

UMTS ArchitectureProtocols used over the Iu CS Interface

Iu CSRANAP

ALCAP

Iu CS FP

SCCP

SAAL - NNI

AAL5

ATM

SAAL - NNI

AAL5

ATM

Data stream

AAL2

ATM

Control Plane User Plane

TransportNetworkControlPlane

The Radio Access NetworkApplication Protocol (RANAP) providesthe following functions :

Relocation functionsOverall RAB ManagementTransport of Non Access Stratum messagesPaging functionsSecurity functionsCN information broadcastOverload control over Iu Interface

Physical layer

RNCRNC

MTP3-B MTP3-B

WirelessGateway

TRAU

UMTS ArchitectureProtocols used over the Iu PS Interface

Iu PSRANAP Iu PS FP

SCCP

SAAL - NNI

AAL5

ATM

Control Plane User Plane

TransportNetworkControlPlane

The Radio Access NetworkApplication Protocol (RANAP) providesthe following functions :

Relocation functionsOverall RAB ManagementTransport of Non Access Stratum messagesPaging functionsSecurity functionsCN information broadcastOverload control over Iu Interface

Physical layer

RNCRNC

MTP3-B

WirelessGateway

GTP-U

SAAL - NNI

AAL5

ATM

UDP

SGSN