UMTS Network Architecture

UMTS Architecture Section 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 Architecture GSM Architecture NSS

PSTN

BSS MSC BTS A bis

BSC

A ter

TCU VLR

MS

C

D

HLR/AuC

UMTS Architecture From GSM to GSM/GPRS Architecture PSTN MSC A

BTS A bis

BSC

A ter

TCU VLR C

MS D

HLR/AuC Gb PCU

Frame Relay Backbone

Gr

Gb

Gn SGSN

IP Backbone

Gn GGSN

UMTS Architecture UMTS Elements in a PLMN Access Network

Core Network

Uu

MSC

TRAU RNC Iu (CS & PS)

Iub (ATM) Node B (BTS)

UE

Iu CS

PSTN

C

Iur

VLR D ATM Backbone

ATM Backbone Gr

Uu

HLR/AuC GGSN

Iur Iu (CS & PS)

Iub (ATM)

Iu PS Gn

Private IP Backbone

Gn

SGSN UE

Node B (BTS)

RNC

Gi

External Packet Networks

UMTS Architecture UTRAN Elements: Node B • Node B – Logical node responsible for radio transmission/reception in one or more cells to/from the UE – Performs and reports radio measurements to the RNC – ATM Termination (Iub) – Inner Loop Power Control

UMTS Architecture UTRAN Elements: RNC • RNC – Responsible for the use and integrity of the radio resources within the RNS – Responsible for the handover decisions that require signaling to the UE – Provides a combining/splitting function to support macro diversity between different Node Bs – ATM Switching and Multiplexing

UMTS Architecture CN 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 switched services 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 Architecture CN 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 area where the MS is registered – The VLR number of the associated VLR (if the Gs interface is implemented) – The GGSN address of each GGSN for which an active PDP context exists

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

UMTS Architecture Overall functions Overall Functions of UTRAN

Overall Functions of CN

• Provision of Radio Coverage

• Switching

• System Access Control

• Mobility Management

• Security and Privacy

• Service Provision

• Handover

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

• Radio Resource Management and Control

• Operations, Administration and Maintenance

UMTS Architecture UE Elements RNC

UE

Node B provides : o Means of communication between UE and the network o 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

CN

UMTS Architecture Protocols used over the Iub Interface

RNC

Iub NBAP

Iub FP ALCAP

Data stream

SAAL - UNI

SAAL - UNI

AAL5

AAL5

AAL2

ATM

ATM

ATM

Physical layer

Control Plane

Transport Network Control Plane

The Node B Application Protocol (NBAP) provides the following functions : Cell Configuration Management System Information Management Resource Event Management Common Transport Channel Management Radio Link Management Measurements on Common Resources Measurements on Dedicated Resources

User Plane

Note : ALCAP is not used by Nortel

UMTS Architecture Protocols used over the Iur Interface

RNC

RNC

Iur RNSAP

Iur FP

SCCP

ALCAP

MTP3-B

MTP3-B

SAAL - NNI

SAAL - NNI

AAL5

AAL5

AAL2

ATM

ATM

ATM

Data stream

Physical layer

Control Plane

Transport Network Control Plane

The Radio Networks Subsystem Application Protocol (RNSAP) provides the following functions : Radio Link Management Measurement reporting function Transfer of UL and DL functions Power Control Load Management Paging functions relocation functions

User Plane

Note : ALCAP is not used by Nortel

UMTS Architecture Protocols used over the Iu CS Interface Wireless Gateway

RNC

TRAU

Iu CS RANAP

Iu CS FP

SCCP

ALCAP

MTP3-B

MTP3-B

SAAL - NNI

SAAL - NNI

AAL5

AAL5

AAL2

ATM

ATM

ATM

Data stream

Physical layer

Control Plane

Transport Network Control Plane

The Radio Access Network Application Protocol (RANAP) provides the following functions :

User Plane

Relocation functions Overall RAB Management Transport of Non Access Stratum messages Paging functions Security functions CN information broadcast Overload control over Iu Interface

UMTS Architecture Protocols used over the Iu PS Interface Wireless Gateway

RNC SGSN

Iu PS RANAP

Iu PS FP

SCCP

GTP-U

MTP3-B

UDP

SAAL - NNI

SAAL - NNI

AAL5

AAL5

ATM

ATM Physical layer

Control Plane

Transport Network Control Plane

User Plane

The Radio Access Network Application Protocol (RANAP) provides the following functions : Relocation functions Overall RAB Management Transport of Non Access Stratum messages Paging functions Security functions CN information broadcast Overload control over Iu Interface