UMTS Signalling

UMTSUniversal MobileTelecommunicationsSystem

Signalling

Signalling protocol details

Chapter contents

» UMTS Protocol Internetworking Architecture

» Part 1: Transport Network Protocols, CS and PS

» Part 2: Radio Network Protocols, CS and PS

» Part 3: System Network Protocols, CS and PS

» Examples of UMTS procedures

UMTS Network Protocol Architecture

Transport Network Layer

Radio Network Layer

System Network Layer

Uu Iub Iu E / Gn

User Plane

Control Plane

User Plane

Control Plane

User Plane

Control Plane

NodeB RNC MSC VLR SGSN GMSC GGSN

UMTS Network Transactions

Uu / Iub – Control-Plane

ATM

AAL2

UP FP

MAC

RLC

RRC

MM/SM/CC

AAL5

SSCOP

SSCF- UNI

STC

AAL2L3 NBAP

WCDMA

MAC

RLC

RRC

MM / SM / CC

NodeB RNC

Uu / Iub – User-Plane

ATM

AAL2

UP FP

MAC

RLC

PDCP BMC

Application data

WCDMA

MAC

RLC

PDCP BMC

Application data

NodeB RNC

Iur – User- / Control-Plane

User-Plane

RRC

ATM

AAL2

UP FP

MAC

RLC

AAL5

SSCOP

SSCF-NNI

IP

SCTP

MTP3-B M3UA

STC

AAL2L3

MM/SM/CC

ATM

AAL2

UP FP

MAC

RLC

PDCP BMC

Application data

Control-Plane

SCCP

RNSAP

RNCRNCRNC

RLP

TAF AMR

IuCS – User- / Control-Plane

User-Plane

ATM

AAL2

Iu UP

Application data

Control-Plane

ATM

AAL5

SSCOP

SSCF-NNI

IP

SCTP

MTP3-B M3UA

SCCP STC

AAL2L3RANAP

MM/SM/CC

RNC RNCMSC

IuPS – User- / Control-Plane

User-Plane

ATM

AAL5

IP

IP

Control-Plane

ATM

AAL5

SSCOP

SSCF-NNI

IP

SCTP

MTP3-B M3UA

SCCP

RANAP

MM / CC / SS

UDP

GTP-U

Application data

RNC RNCSGSN

E – User- / Control-Plane

Control-Plane

PCM

MTP-L2

MTP-L3

User-Plane

Application data

SCCP

TCAP

MAP

PCM

ISUP

MSCVLR

MSCVLR

MSCVLR

Gn – User- / Control-Plane

Control-Plane

ATM

AAL5

Ethernet

IP

UDP

ATM

AAL5

Ethernet

IP

UDP

GTP-U

User-Plane

IP

Application data

GTP-C

SGSN GGSN SGSN

Signalling Part 2

Radio Network Layer

ASN.1

RRC, NBAP, RNSAP and RANAPAAL2L3 (ALCAP)

Iu UP, AMR, TAF, RLPPDCP and BMC

RRC

» Radio Resource Control

» Routing of higher layer messages to different MM/CM entities (UE side) or different core network domains

» Creation and management of Radio Bearers

» Broadcasting of System Information

» Paging of UEs

» Dedicated Control handles all functions specific to one UE

» Location Management

» Handover

» Power Management (outer loop power control)

» Configuration of lower layer protocols

» Management of measurement reports

» Specified in 3GPP 25.331

RRC States

Idle Mode

Camping on a UTRAN cell Camping on a GSM cellGPRS idle mode

UTRAN Connected Mode

CELL_DCH CELL_FACH

URA_PCH CELL_PCH

EstablishDedicated

RRC-Connection

ReleaseDedicated

RRC-Connection

EstablishSharedRRC-

ConnectionReleaseSharedRRC-

Connection GPRSPacket

TransferMode

Initof

TBF

Rel.of

TBF

GSM Connected

Mode

EstablishRR-

Connection

ReleaseRR-

Connection

GSM: Handover

UTRAN: Inter-RAT Handover

Cellreselection

RRC – UMTS Connected Mode States

UTRAN Connected Mode

CELL_DCH

CELL_PCH

Release last dedicated channel

Allocation of dedicated channel

RRC State Indicator:URA_PCH

RRC Sta

te In

dicato

r: URA_PCH

RRC State Indicator:

CELL_PCH

Pagingor

Init. UL transfer

Paging o

r Init.

UL tr

ansfer

CELL_FACH

URA_PCH

RRC Connection Establishment

„ ... a point-to-point bi-directional connection between RRC peer entitiesin the UE and the UTRAN characterised by the allocation of a U-RNTI.

A UE has either zero or one RRC connection.“RNC

( RLC-SAP: TM, CCCH ) RRC CONNECTION REQUEST

[ RRC TAId, Initial UE Id, Establishment Cause ]

( RLC-SAP: UM, CCCH ) RRC CONNECTION SETUP

[ RRC TAId, new U-RNTI, SRB ]

( RLC-SAP: AM, DCCH ) RRC CONNECTION SETUP COMPLETE

[ RRC TAId, UE Radio Acces Capability ]Successful

Unsuccessful ( RLC-SAP: TM, CCCH ) RRC CONNECTION REQUEST

[ RRC TAId, Initial UE Id, Establishment Cause ]

( RLC-SAP: UM, CCCH ) RRC CONNECTION REJECT

[ RRC TAId, Cause ]

Idle

Connected

RRC Connection Release

RNC

( RLC-SAP: UM, DCCH ) RRC CONNECTION RELEASE

[ RRC TAId, Release Cause ]

( RLC-SAP: UM / AM, DCCH ) RRC CONNECTION RELEASE COMPLETE

[ RRC TAId ]

( RLC-SAP: UM, CCCH ) RRC CONNECTION RELEASE

[ U-RNTI, RRC TAId, Release Cause ]

RRC Signalling Connection

RNC

( RLC-SAP: AM, DCCH ) INITIAL DIRECT TRANSFER

[ CN Domain Id, NAS SDU ]

( RLC-SAP: AM, DCCH ) UPLINK DIRECT TRANSFER

[ CN Domain Id, NAS SDU ]

( RLC-SAP: AM, DCCH ) DOWNLINK DIRECT TRANSFER

[ RRC TAId, CN Domain Id, NAS SDU ]

( RLC-SAP: AM, DCCH ) SIGNALLING CONNECTION RELEASE

[ RRC TAId, CN Domain Id ]

RRC Radio Bearer Setup

RNC

( RLC-SAP: AM, DCCH ) RADIO BEARER SETUP * COMPLETE

[ RRC TAId ]

( RLC-SAP: AM, DCCH ) RADIO BEARER SETUP *

[ RRC TAId, SRB and RB Info / List etc. ]

( RLC-SAP: AM, DCCH ) RADIO BEARER SETUP * FAILURE

[ RRC TAId , Failure Cause ]

( RLC-SAP: AM, DCCH ) RADIO BEARER SETUP *

[ RRC TAId, SRB and RB Info / List etc. ]

NBAP

» Node B Application Part

» Cell Configuration Management

» Common Transport Channel Configuration

» System Information Management

» Resource Event Management

» Measurements on common and dedicated resources

» Radio Link Management of dedicated resources

» Radio Link Supervision


NBAP Elementary Procedure

» Two classes of elementary procedures:

» Class 1: Elementary procedure with response,

success or failure

» Class 2: Elementary procedure without response

» NBAP Initiating Message is transporting the procedure request

» For Class 1 elementary procedure the response is transmitted

» Success: Successful Outcome Message

» Failure: Unsuccessful Outcome Message

» The elementary procedure is identified by the parameter

Procedure Identification Code.

» The CRNC Communication Context contains all info for the CRNC tocommunicate with a specific UE.

» The Context is identified by the parameter

CRNC Communication Context Identifier.

NBAP Example Procedure

RNC

INITIATING MESSAGE

[ Procedure Code: RADIO LINK SETUP,

Transaction-Id, C-Id, Channel parameter ]

NodeB

SUCCESSFUL OUTCOME


Transaction-Id, Channel parameter ]Successful

Unsuccessful

INITIATING MESSAGE


Transaction-Id, C-Id, Channel parameter ]

UNSUCCESSFUL OUTCOME


Transaction-Id, Cause ]

RANAP

» Radio Access Network Application Part

» Transfer of NAS-PDU between CN and UTRAN

» Overall RAB management

» Relocating of SRNC

» Controlling the security mode of UTRAN

» Paging the UE

» Release of RAB and the Iu connection resources

» SCCP uses SSN=142 for RANAP identification


RANAP Elementary Procedure

» Three classes of elementary procedures:

» Class 1: Elementary procedure with response

( success and / or failure )

» Class 2: Elementary procedure without response

» Class 3: Elementary procedure with possibility of

multiple responses ( success and/or failure )

» RANAP Initiating Message is transporting the procedure request

» For Class 1 elementary procedure the response is transmitted

» Success: Successful Outcome Message

» Failure: Unsuccessful Outcome Message

» For Class 3 elementary procedure the response is transmitted as

Outcome Message

RANAP Example Procedure

RNC

INITIATING MESSAGE

[ Procedure Code: INITIAL UE MESSAGE,

CN Domain Id, LAI, SAI, Iu Signal.Conn.Id, NAS PDU ]

INITIATING MESSAGE

[ Procedure Code: SECURITY MODE CONTROL,Integrity protection info, key status ]

SUCCESSFUL OUTCOME

[ Procedure Code: SECURITY MODE CONTROL,Integrity protection algorithm ]

MSC

Class 2

Class 1

INITIATING MESSAGE

[ Procedure Code: RAB ASSIGNMENT,RAB Id and Info, Cause ]

OUTCOME

[ Procedure Code: RAB ASSIGNMENT,Success or failure IEs for RAB Id and Info ]

Class 3

Signalling Part 3

System Network LayerCircuit Switched:

Mobility Management and Call Control

control plane between CN nodes

Packet Switched:Mobility and Session Management

control plane between CN nodes

Location Based Services

CS Mobility Management

» Procedures well known from GSM

» MM procedures to establish and release connections.

» Transfer of Call Management (CM) sublayer messages.

» MM common procedures for security functions, e.g.

Authentication procedure.

» MM specific procedures for location functions like

Periodic location updating or IMSI attach procedure.

» UE identified by IMSI or TMSI.


CS Call Control

» Procedures well known from GSM

» CC establishes and releases CC connections between UE and

CN.

» Activation of voice/multimedia codec.» Based on 3G-324M, variant of H.324. See 3GPP 26.111.

» Interworking with RANAP for establishment of a RAB.» CC SETUP QoS will be mapped onto RANAP RAB assignment.


CS MOC Example

MM: CM Service Request[ Mobile Identity, MS Classmark ]

MM: CM Service Accept

MSC VLR

CC: Setup[ Called Party Number, Bearer Capability ]

CC: Call Proceeding

CC: Alert

CC: Connect

CC: Connect Ack.

MM: Authentication Request

MM: Authentication Response

Call set-up

Call release CC: Disconnect [ Cause ]

CC: Relase

CC: Reease Complete

PS Mobility Management

» Procedures well known from GPRS (GMM)

» GMM protocol makes use of a signalling connection between UE and SGSN.

» GMM establishes and releases GMM contexts, e.g. GPRS Attach.

» GMM specific procedures for location functions likePeriodic routing area updating.

» New message implemented to provide service to CM sublayer on topof GMM:

» SERVICE REQUEST message

» Initiated by UE, used to establish a secure connection to the network and

to request the bearer establishment for sending data.

» UE identified by IMSI or P-TMSI


PS Session Management

» Procedures well known from GPRS (SM)

» Counterpart to CS CC protocol, i.e.

it is used to establish and release packet data sessions.

» SM procedures to setup and release one or more

PDP contexts.

» PDP Contexts are handled in UE and GGSN.

» SGSN represents interworking function.


PS Activate PDP Context Example

GMM: Service Request[ Mobile Identity, MS Classmark ]

GMM: Service Accept

SM: Activate PDP Context Request[ APN, Type of PDP-Address, QoS ]

SM: Activate PDP Context Accept[ PDP-Address, QoS ]Connection

set-up

Connectionrelease SM: Deactivate PDP Context Request

SM: Deactivate PDP Context Accept

SGSN

Iu Procedures

• Location Update on IuCS

• MOC on IuCS

• MTC on IuCS

• Attach on IuPS

• PDP Context on IuPS

Location Update on IuCS 1/2

NodeB

Initial Direct Transfer [ NAS: LUREQ ]

DL Direct Transfer [ NAS: AUTREQ ]

RNC MSC

CR – RANAP: * Initial UE Message [ MM: LUREQ ]

CC

DT1 – RANAP: * Direct Transfer [ MM: AUTREQ ]

UL Direct Transfer [ NAS: AUTRESP ]DT1 – RANAP: * Direct Transfer [ MM: AUTRESP ]

DT1 – RANAP: * Common ID

* : Initiating Message

RRC Connection Setup

RRC Connection Request

NBAP: Radio Link Setup

AAL2L3: Establish

Location Update on IuCS 2/2

NodeB

DL Direct Transfer [ NAS: LUACC ]

RNC MSC

DT1 – RANAP: * Direct Transfer [ MM: LUACC ]

DT1 – RANAP: InitiatingMsg [ Iu Release ]RRC Connection Release

DT1 – RANAP: SuccOutcome [ Iu Release ]

NBAP: Radio Link Deletion

RLSD

RLC

AAL2L3: Release

Security Mode CompleteDT1 – RANAP: SuccOutcome [ Security Mode Control ]

Security Mode Command DT1 – RANAP: InitiatingMsg [ Security Mode Control ]


MOC on IuCS 1/4

NodeB

Initial Direct Transfer [ NAS: CMSREQ ]


RNC MSC

CR – RANAP: * Initial UE Message [ MM: CMSREQ ]

CC




Security Mode Command

Security Mode Complete

DT1 – RANAP: InitiatingMsg [ Security Mode Control ]

DT1 – RANAP: SuccOutcome [ Security Mode Control ]


UL Direct Transfer [ NAS: SETUP ]DT1 – RANAP: * Direct Transfer [CC : SETUP ]

MOC on IuCS 2/4

NodeB RNC MSC


DL Direct Transfer [ NAS: CPROC ]DT1 – RANAP: * Direct Transfer [ MM: CPROC ]

DT1 – RANAP: InitiatingMsg [ RAB Assignment ]

NBAP: Synchronised Radio LinkReconfiguration Preparation

AAL2L3: Establish Request

AAL2L3: Establish Confirm



Iu UP: ProcCode [ Initialisation ]

Iu UP: Ack

Radio Bearer Setup

DT1 – RANAP: Outcome [ RAB Assignment ]

MOC on IuCS 3/4

NodeB RNC MSC


DL Direct Transfer [ NAS: ALERT ]DT1 – RANAP: * Direct Transfer [CC : ALERT ]

Iu UP: Type 0 [ AMR data ]

DL Direct Transfer [ NAS: CONNECT ]DT1 – RANAP: * Direct Transfer [CC : CONNECT ]

DL Direct Transfer [ NAS: CONN ACK ]DT1 – RANAP: * Direct Transfer [CC : CONN ACK ]



DL Direct Transfer [ NAS: DISC ]DT1 – RANAP: * Direct Transfer [CC : DISC ]

DL Direct Transfer [ NAS: RELEASE ]DT1 – RANAP: * Direct Transfer [CC : RELEASE ]

DL Direct Transfer [ NAS: REL COMP ]DT1 – RANAP: * Direct Transfer [CC : REL COMP ]

MOC on IuCS 4/4

NodeB RNC MSC

DT1 – RANAP: InitiatingMsg [ Iu Realease ]RRC Connection Release

AAL2L3: Release Request

AAL2L3: Release Confirm

AAL2L3: Relase ( DTCH )



AAL2L3: Relase ( DCCH )

RLSD

RLC

MTC on IuCS 1/5

NodeB

( PCH ) Paging Type 1

RNC MSC

UDT – RANAP: Paging


AAL2L3: Establish ( DCCH )


UL – DL – SYNC



RRC Connection Setup Comp

Initial Direct Transfer [ NAS: PRES ]CR – RANAP: * Initial UE Message [ MM: PRES ]

CC

MTC on IuCS 2/5

NodeB


RNC MSC









DL Direct Transfer [ NAS: SETUP ]DT1 – RANAP: * Direct Transfer [CC : SETUP ]

UL Direct Transfer [ NAS: CCONF ]DT1 – RANAP: * Direct Transfer [CC : CCONF ]

MTC on IuCS 3/5

NodeB RNC MSC


Synchronised Radio LinkReconfiguration Preparation





Iu UP: ProcCode [ Initialisation ]

Iu UP: AckNBAP: Radio Bearer Setup


MTC on IuCS 4/5

NodeB RNC MSC


DL Direct Transfer [ NAS: ALERT ]DT1 – RANAP: * Direct Transfer [ CC: ALERT ]


DL Direct Transfer [ NAS: CONNECT ]DT1 – RANAP: * Direct Transfer [ CC: CONNECT ]

DL Direct Transfer [ NAS: CONN ACK ]DT1 – RANAP: * Direct Transfer [ CC: CONN ACK ]



DL Direct Transfer [ NAS: DISC ]DT1 – RANAP: * Direct Transfer [CC : DISC ]

DL Direct Transfer [ NAS: RELEASE ]DT1 – RANAP: * Direct Transfer [CC : RELEASE ]

DL Direct Transfer [ NAS: REL COMP ]DT1 – RANAP: * Direct Transfer [CC : REL COMP ]

MTC on IuCS 5/5

NodeB RNC MSC


AAL2L3: Release Request

AAL2L3: Release Confirm





RLSD

RLC

Attach on IuPS 1/2

NodeB



Initial Direct Transfer [ NAS: ATRQ ]

DL Direct Transfer [ NAS: ACRQ ]

RNC

CR – RANAP: * Initial UE Message [ GMM: ATRQ ]

CC

DT1 – RANAP: * Direct Transfer [ GMM: ACRQ ]

UL Direct Transfer [ NAS: ACRE ]DT1 – RANAP: * Direct Transfer [ GMM: ACRE ]



AAL2L3: Establish

SGSN

Attach on IuPS 2/2

NodeB

DL Direct Transfer [ NAS: ATAC ]

RNC MSC

DT1 – RANAP: * Direct Transfer [ GMM: ATAC ]

DT1 – RANAP: InitiatingMsg [ Iu Release ]RRC Connection Release



RLSD

RLC

AAL2L3: Release

Security Mode CompleteDT1 – RANAP: SuccOutcome [ Security Mode Control ]

Security Mode Command DT1 – RANAP: InitiatingMsg [ Security Mode Control ]

UL Direct Transfer [ NAS: ACOM ]DT1 – RANAP: * Direct Transfer [ GMM: ACOM ]


PDP Context on IuPS 1/3

NodeB

Initial Direct Transfer [ NAS: SREQ ]

DL Direct Transfer [ NAS: ACRQ ]

RNC MSC

CR – RANAP: * Initial UE Message [ GMM: SREQ ]

CC

DT1 – RANAP: * Direct Transfer [ GMM: ACRQ ]

UL Direct Transfer [ NAS: ACRE ]DT1 – RANAP: * Direct Transfer [ GMM: ACRE ]








NodeB RNC MSC



NBAP: Synchronised Radio LinkReconfiguration Preparation

AAL2L3: Establish

NBAP: Radio Bearer Setup


DL Direct Transfer [ NAS: APCA ]DT1 – RANAP: * Direct Transfer [ SM : APCA ]

UL Direct Transfer [ NAS: APCR ]DT1 – RANAP: * Direct Transfer [SM : APCR ]

Application data flowon dedicated VPI/VCI

using AAL5


NodeB RNC MSC






RLSD

RLC

UL Direct Transfer [ NAS: DPCR ]DT1 – RANAP: * Direct Transfer [SM : DPCR ]

DL Direct Transfer [ NAS: DPCA ]DT1 – RANAP: * Direct Transfer [ SM : DPCA ]

CS-Control Plane between CN nodes

» Standard SS#7 protocols are used as control plane transport layers.

» For circuit switched procedures ISDN user part is used to setup connections and to control the traffic channel.

» Procedures for network specific functions are handled by the MAPprotocol, known from GSM/GPRS.

» Procedures for subscriber specific functions are handled by INAP and CAP protocol, also know from GSM/GPRS.

» More or less old specification numbers are used. Version number will indicate the type of network standard (GSM, GPRS or UMTS)

GPRS Tunneling Protocol Interfaces

» Three types of GTP protocols1. GTP – Control Plane

2. GTP – User Plane

3. GTP‘

other PLMN

SGSN GGSN

CGF

SGSN

SGSN

UTRAN

UTRAN

3.

1. + 2.

2.

2.

GTP

» Tunnel is identified by Tunnel Endpoint Identifier

» C-Plane: TID-C; U-Plane: TID-D (Data)

» GTP-C:» Establish, management and release of user specific tunnels between

GSNs for exchange of signalling information.

» supports creation, modification and deletion of PDP Contexts

» supports mobility management (relocation of RNC)

» GTP-U:» Transport of application data

» GTP‘:» Transport of charging data records from SGSN and GGSN to Charging

Gateway.


GTP – C and – U Example

GTP-C-TM: Create PDP Context Request[ TID-C, DL-TID-D, MSISDN, NSAPI, APN, PDP-Info ]

GTP-C-TM: Create PDP Context Response[ TID-C, UL-TID-D, PDP-Address, Cause ]

PDP Contextset-up

PDP Contextrelease

SGSN GGSN

GTP-U: Tunnel-PDU[ UL-TID-D, ]

GTP-U: Tunnel-PDU[ UL-TID-D, ]

GTP-U: Tunnel-PDU[ DL-TID-D, ]

GTP-C-TM: Delete PDP Context Request[ TID-C, NSAPI, Teardown Ind ]

GTP-C-TM: Delete PDP Context Response[ TID-C, Cause ]

UMTS Signalling

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