05 - Introduction to UMTS Signalling and Interface2_emad

1 © NOKIA Kittipong Thamapa

Introduction to 3G/UMTS Introduction to 3G/UMTS Signalling and InterfacesSignalling and Interfaces


Module topics

• Introduction to 3G/UMTS signalling

• Transport layer signalling and interfaces

• Control layer signalling and interfaces

• User layer signalling and interfaces

• Summarised function of the 3G/UMTS interfaces


Bearer & Signalling

UE BTS RNC

Uu Iub/Iur Iu

Core Network

MSC

3G

SGSN

RNCWCDMA BTS

Keypoint:

Define signalling - Communication between different network elements, control processes, enable bearers/communication.

Signalling protocols - standardised set of rules on how the communication should take place, what messages to exchange, etc.


3G/UMTS Session Management

CNRAN

RRC Connection

UE

CircuitSwitchedNetwork

PacketNetwork

Radio Access Bearer

Speech Service

Video Service

Radio Access BearerPacket Data Service

Radio Access Bearer

RANAP Connection

RANAP Connection

Key points:

RAB - Radio Access Bearer = service connection between the terminal and the core network.

User plane = User Data.

Signalling links are used to inform the different network elements on how to control the Radio Resource Connection.


BS RNCMTUSIM Core Network Domains:

- MSC & GMSC (Circuit Switched)

- SGSN & GGSN (Packet Switched)

3G network structure

Access Stratum

Serving Stratum

Application Stratum

Stratum is collection of protocols

ATM

SignallingProtocol

User Data

The different Stratums:

- Access Stratum: Message Flows, rules and procedures on how to establish the connection between the MT and the network (RNC).

- Serving Stratum: Signalling messages that are used to enable/establish services (bearer setup).

- Application Stratum: High-layer stratum, which contains signalling procedures to enable the usage of applications. When connecting to external networks (such as the Internet), the protocols and procedures must of course be supported all the way between the end-points.

Compare this with the serving stratum and application stratum, which are both defined internally in the UMTS network.

3GPP 23.101.


OSI model

Transport Layer Transport Layer

Session Layer Session Layer

Presentation Layer Presentation Layer

Application Layer Application Layer

User Data Control Data

Network Layer

Data (Link) Layer

Physical Layer

User Plane Control Plane

Transport Plane

Access Stratum

Serving StratumApplication

Stratum


General protocol modelfor UTRAN terrestrial interfaces

TransportNetworkLayer

RadioNetworkLayer

ALCAP(s)

Signalling Bearer(s)

Application Protocol


Data Stream(s)

Data Bearer(s)

User PlaneControl Plane

TransportNetwork

Control Plane

TransportNetwork

User Plane

TransportNetwork

User Plane

Physical Transmission layer

ALCAP Access Link Control Application Part

All UTRAN-related issues are visible only in the radio network layer

Used for all 3G specific control signalling such as setting up bearers to the UE

- RANAP in Iu - RNSAP in Iur - NBAP in Iub- etc.

Always set up by O&M

Used for all control signalling within the transport network layer

Used to set up and tear down data bearers for the user plane

Always set up by O&M

•Horizontal Layers

The protocol structure consists of two main layers, the Radio Network Layer and

the Transport Network Layer. All UTRAN related issues are visible only in the Radio Network

Layer. The Transport Network Layer represents standard transport technology that is selected

to be used for the UTRAN but without any UTRAN specific changes.

•Vertical Planes

⇒Control Plane

The Control Plane is used for all UMTS specific control signalling. It includes the

Application Protocol (i.e. RANAP in Iu, RNSAP in Iur, NBAP in Iub) and the Signalling

Bearer for transporting the Application Protocol messages.

The Application Protocol is used, among other things, for setting up bearers to the

UE (i.e. the Radio Access Bearer in Iu and subsequently the Radio Link in Iur and Iub).

The Signalling Bearer for the Application Protocol is always set-up by O&M

actions.

The protocol structures in UTRAN terrestrial interfaces (Iu, Iur, Iub) are designed according to the same

general protocol model. The structure is based on the principle that the layers and planes are logically

independent of each other and, if needed, parts of the protocol structure may be changed in the future

while other parts remain intact.


Transport plane (≈≈≈≈Access Stratum)

• Defines how physical connection is established between the mobile terminal and the network

• In the Uu interface, WCDMA/FDD is used

• In the UTRAN interfaces, ATM will be used:

- Iub

- Iur

- Iu-CS, Iu-PS

BS RNCMTUSIM

Access Stratum

CN


Synchronous and Asynchronous Multiplexing

CACCC

A A

C C C C

A

CACAB

A A

BB B BB B B B

BB BB B

C

ABC

Asynchronous Multiplexing

Synchronous Multiplexing

C

BB

CC

B

C

• Asynchrounous Multiplexing can utilise the transmission capacity more flexibly

• ATM provides a "bit pipe" by providing Virtual Circuits


Why is the ATM selected as a transport network in 3G?

• ATM provides efficient support for transmission of voice, data, and video

• ATM provides QoS guarantee and reliability

• ATM utilises statistical multiplexing, so

less bandwidth can be reserved

transmission cost saving are considerable

• ATM supports the soft handover functionality


ATM cell

• Always the same payload - 48 bytes (octets)

• Overhead is almost 9.5%, due to the 5-octet header

• Can carry any type of information

• Two types of ATM cells

• ATM UNI (User-Network Interface) cell; used for communicationbetween ATM endpoints and ATM switches

• ATM NNI (Network-Node Interface) cell; used forcommunication between ATM switches

Header5 bytes

Payload48 bytes

53 bytes


Virtual Path (VP)

Virtual Channel (VC)

ATM CellVirtual Channel

Virtual Path

• Virtual Channel = Virtual Circuit

• Virtual Paths = Logical grouping of Virtual Circuits → an ATM switch can perform operations on groups of Virtual Circuits

• Transmission Path= A bundle of Virtual Paths

Virtual Path, Virtual Channel, Transmission Path

Virtual Path is a semi-permanent connection simultaneously handling many virtual connections/channels. Actual data is transferred in ATM cells over the Virtual Channels

A group of Virtual paths between two network elements forms a Transmission Path.


Transmission Path, VP, VC and ATM Cell

Transmission pathVirtual PathVirtual Channel (VC)ATM Cell


ATM resource management (Iu-CS)

RNC MGW

AT

M lo

gic

al in

terfa

ce

VP

Ltp

,V

PL

tp,

VP

Ltp

,

VC

Ltp

AT

M lo

gic

al in

terfa

ce

For RANAP, AAL2 (MTP3SL) signalling

VC

Ltp

VP

Ltp

,V

PL

tp,

VC

Ltp

VC

Ltp

User traffic

VC

Ltp

3

1

4

2

Access profile of ATM interface- max bandwidth- max VPI/VCI bits- max VPC/VCC

- VPI- VPL service level: VP/VC- usage e.g. MTP3SL, AAL2UD, IPOAM, AAL2SL, DNBAP, CNBAP- service category: CBR/UBR- traffic and QoS parameters

- interface id- UNI / NNI- IMAGR/PET/ SET

- VCI- service category- traffic and QoS parameters

O&M traffic (UBR, IPOAM)

Signalling traffic (CBR, MTP3SL)

User traffic (CBR, AAL2UD)

User traffic

VC

Ltp

VP

Ltp

,V

CL

tpV

CL

tp


ATM UNI cell header - Content

VCI

GFC VPI

VPI

VCI

VCI PT CLP

HEC

123457 68

Payload

Header

(5 bytes)

Payload

(48 bytes)

GFC Generic Flow Control

GFC Provides local functions, such as identifying multiple stations that share a

single ATM interface. This field is typically not used and is set to its default value.

VPI Virtual Path Identifier

VPI: In conjunction with the VCI, identifies the next destination of a cell as it passes

through a series of ATM switches on the way to its destination.

VCI Virtual Channel Identifier

VCI: In conjunction with the VPI, identifies the next destination of a cell as it passes

through a series of ATM switches on the way to its destination.

PT Payload Type

PT: Indicates in the first bit whether the cell contains user data or control data. Ifuser data, the second bit indicates congestion, and the third bit indicates whether

the cell is the last in a series of cells that represent a single AAL5 frame.

CLP Cell Loss Priority

CLP: Indicates whether the cell should be discarded if there is congestion in thenetwork. If the CLP bit equals 1, the cell should be discarded in preference to cells

with the CLP bit equal to zero.

HEC Header Error Control

HEC: Calculates checksum only on the header itself.

Any cell that fails the header error check is instantly discarded by the network.

Generic Flow Control (GFC)Provides local functions, such as identifying multiple stations that share a single ATM interface. This field is typically not used and is set to its default value.

Virtual Path Identifier (VPI)In conjunction with the VCI, identifies the next destination of a cell as it passes through a series of ATM switches on the way to its destination.

Virtual Channel Identifier (VCI)In conjunction with the VPI, identifies the next destination of a cell as it passes through a series of ATM switches on the way to its destination.

Payload Type (PT)Indicates in the first bit whether the cell contains user data or control data. If the cell contains user data, the second bit indicates congestion, and the third bit indicates whether the cell is the last in a series of cells that represent a single AAL5 frame.

Congestion Loss Priority (CLP)Indicates whether the cell should be discarded if there is congestion in the network. If the CLP bit equals 1, the cell should be discarded in preference to cells with the CLP bit equal to zero.

Header Error Control (HEC)Calculates checksum only on the header itself. Any cell that fails the header error check is instantly discarded by the network.


ATM protocol layers

• Physical layer defines the transmission medium.

• ATM layer inserts and extracts the cell header. It also takes care of multiplexing and switching of cells.

• AAL maps user data from higher layer into standard ATM cells to be transported over an ATM network. It also collects information from ATM cells for delivery to higher layers.

PHYSICAL LAYER

ATM LAYER

AALATM ADAPTATION LAYER


ATM layer functions

Convergence Sublayer (CS)

PayloadPayload HeaderHeader

48 bytes5 bytes

User data

AAL

Segmentation and Reassembly Sublayer (SAR)

ATM Layer

Transmission Convergence (TC)

48 bytes

Physical Medium Dependent(PMD)

SD

H O

/H

PayloadHeader

Scramble frame and adapts the signals to the optical or electrical transmission medium

STM-1 Frame

Physical Layer


ATM Adaptation Layer

Typical

Use

FixedConnection

Video&

Audio

FrameRelay

IPServices

AAL AAL1 AAL2 AAL3/4 AAL5

Connection OrientedConnection oriented or

connectionless

Synchronised Not Synchronised

Constant VariableBit Rate

Source & Dest.

Connection

ATM Layer

Physical Layer

A B C D

ATM Service Classes

Convergence Sublayer

Segmentation and ReassemblySublayer

AAL

CS

SAR

Higher Protocol Layers

ATM Layer

AAL2 is seen as a suitable option for Iu-CS (Circuit Switched), Iur, and Iub user plane connections

AAL5 is seen suitable for control information and Iu-PS (Packed Switched) user plane data transfer.

The main difference between AAL2 and AAL5 is that AAL2 requires timing between the source and destination. AAL2 is thus suitable for real-time services such as speech, while AAL5 works fine in a non real-time environment.

************************************************************************************************

AAL is divided into two sublayers: CS (Convergence sublayer) and SAR (Segmentation and Re-assembly sublayer). The CS sublayer adapts AAL to the upper protocol layers and the SAR splits data to be transmitted into suitable payload pieces, and in receiving direction it collects payload pieces and unites them back to original data flow. Depending on the case, the CS sublayer may be divided further on into smaller entities.


ATM protocol for signalling and user data

Physical layer

ATM layer

SignallingAAL

AAL

Signalling protocol User data

C-Plane U-Plane

AAL 2 – Iu-CS

AAL5 – Iu-PSAAL 5


Iu Transport PlanesRNCBS

Physical Layer Physical Layer

ATM ATM

AAL2 AAL2AAL5 AAL5

Control

Data

Control

Data

User

Data

User

Data

Iub

DRNCSRNC


ATM ATM

AAL2 AAL2AAL5 AAL5

Control

Data

Control

Data

User

Data

User

Data

Iur

RNC


ATM ATM

AAL2 AAL2AAL5 AAL5

Control

Data

Control

Data

User

Data

User

Data

Iu-CSCS Core Network Domain

RNC


ATM ATM

AAL5 AAL5AAL5 AAL5

Control

Data

Control

Data

User

Data

User

Data

Iu-PSPS Core Network Domain

In the Iub interface the transport plane consists of ATM (Asynchronous Transfer Mode) and its adaptation layer(s) located on top of the physical layer. The physical layer could be any media providing constant bit rate with adequate bandwidth, that is, PCM(s), PDH or SDH.

In the Iur interface between SRNC and DRNC the construction of the transport plane is similar as in the Iub, and in the Iu-CS interface too!

=>In all Iub, Iur and Iu-CS interfaces ATM uses two adaptation layers: AAL2 and AAL5.


Iu -CS UP

A/µ-law,PCM,UDI,etc.

WCDMAL1

MAC

RLC-U

E.g. Vocoder

PHY

ATM

AAL2

FP

WCDMAL1

PHY PHY

ATM ATM

AAL2 AAL2

FP

MAC

RLC-U

PHY PHY

ATM

AAL2

Iu -CS UP

E.g. Vocoder

Link Layer

PHY PHY

Link Layer

A/µ-law,PCM,UDI,etc.

PSTNN-ISDN

PSTNMGW MSCRNCBSUE

A BIu-CSIubUu

PHY

ATM

AAL5

SSCOP

SSCF-UNI

PHY

ATM

AAL5

SSCOP

SSCF-NNI

MTP3b

SCCP

RANAPNBAP

PHY

ATM

AAL5

SSCOP

SSCF-UNI

NBAP

PHY

ATM

AAL5

SSCOP

SSCF-NNI

MTP3b

SCCP

RANAP

PHY

TDM

MTP

SCCP

BSSAP

PHY

TDM

MTP

SCCP

BSSAP

UNI NNI

USER PLANE

CONTROL PLANE

Protocol Stack for Circuit Switched Data


Protocol Stack for Packet Switched Data

PHY

ATM

AAL5

SSCOP

SSCF-UNI

PHY

ATM

AAL5

SSCOP

SSCF-NNI

MTP3b

SCCP

RANAPNBAP

PHY

ATM

AAL5

SSCOP

SSCF-UNI

NBAP

PHY

ATM

AAL5

SSCOP

SSCF-NNI

MTP3b

SCCP

RANAP

RNC SWU MSC

GTP-U

UDP

ATM ATM

WCDMAL1

MAC

RLC-U

PDCP

E.g.IPv4, IPv5

PHY

ATM

FP

PHY PHY

AAL2AAL2WCDMAL1

AAL5

FP LLC/SNAP

MAC IP

RLC-U

PDCP

ATM

AAL5

LLC/SNAPLink

Layer

IP IP

GTP-U

UDP

PHY PHY PHY

LinkLayer

IP

UDP

E.g. IPv4, IPv5

PHY

GTP-U GTP-U

UDP

IPnetwork

SGSN GGSNRNCBS

Iu-PSIubUu

UNI NNI

USER PLANE

CONTROL PLANE

Gn Gi

UE

SAAL NNISAAL UNI


CCS7 lower layers (review from GSM courses)

Message Transfer Part (MTP)

Data Link Layer

Physical Layer


Signalling network(review from GSM courses)

Node A Node B

Node C

SignallingRoutes

Signalling Route Set

SPC SPC

STP

Terminology: Terminology:

• Signalling Point

• Signalling Transfer Point

• Signalling Link

• Signalling Link Set

• Signalling Route

• Signalling Route Set


Transport network control plane

TransportNetworkLayer

RadioNetworkLayer

ALCAP(s)


Application Protocol


Data Stream(s)

Data Bearer(s)

User PlaneControl Plane

TransportNetwork

Control Plane

TransportNetwork

User Plane

TransportNetwork

User Plane

Physical Transmission layer

For setup connection of Transport Network Layer


Main interfaces in Release 3MSC

TCSM

RAN Mobility Core

BSCMSC

MGW

2GSGSN

3G

SGSN

RNC

RNC

A

Iu-PS

Gb

Iu-CS

Abis

Iub

IurIPBB

HLR

GGSNIP Backbone

GSM BTS

Triple Mode BTS

WCDMA BTS

WCDMA BTS

PSTN

NMS

The focus in this chapter is to look at the interfaces and protocols.

Earlier, we have been more element-orientated (Architecture Module) and Traffic Management orientated.


Control plane (≈≈≈≈ Serving Stratum)Main protocols:Main protocols:

• NBAP Node B Application Part - Iub interface

• RNSAP/Radio Network Subsystem Application Part → Iur interface

• RANAP/Radio Access Network Application Part→ Iu interfaces (CS and PS)

• Also MAP and ISUP are presented

BS RNCMT

Access Stratum

Serving Stratum

ATM

USIM CN

SignallingProtocol


Iub interface (NBAP)

RNCBS


ATM ATM

AAL5

NBAP NBAP

Convergence Protocol(s) Convergence Protocol(s)

AAL5

Iub

Common NBAP procedures:Common NBAP procedures:

• Create UE contexts (needed before dedicated signalling procedures can take place).

• Control BCCH information

Dedicated NBAP procedures:Dedicated NBAP procedures:

• Related to specific UE context, examples:

• Radio link addition,reconfiguration, deletion

• Downlink power control

• Dedicated measurement signalling

Common NBAP procedures are used to create new User Equipment (UE) contexts and control BCCH broadcast information. The Iub always contains one signalling link for the common NBAP procedures, and there may be several signalling links for dedicated NBAP procedures.When a UE establishes connection to the network, the control plane is taken into use.After establishing the control plane, the UE may start to use its own applications, which may require signalling too (user plane).Control plane means the signalling resources attached for signalling connection set-up issues between two signalling nodes. In case of Iub interface, the control plane is established between the BS and the RNC, and signalling connection set-up case is radio link set-up.

From Specs: Rel'99; 24.433: "" The NBAP protocol provides the following functions:

- Cell Configuration Management. This function gives the CRNC the possibility to manage the cell configuration information in a Node B.- Common Transport Channel Management. This function gives the CRNC the possibility to manage the configuration of Common Transport Channels in a Node B.- System Information Management. This function gives the CRNC the ability to manage the scheduling of System Information to be broadcast in a cell.- Resource Event Management. This function gives the Node B the ability to inform the CRNC about the status of Node B resources.- Configuration Alignment. This function gives the CRNC and the Node B the possibility to verify and enforce that both nodes have the same information on the configuration of the radio resources.- Measurements on Common Resources. This function allows the Node B to initiate measurements in the Node B. The function also allows the Node B to report the result of the measurements.- Radio Link Management. This function allows the CRNC to manage radio links using dedicated resources in a Node B.- Radio Link Supervision. This function allows the CRNC to report failures and restorations of a Radio Link.- Compressed Mode Control [FDD]. This function allows the CRNC to control the usage of compressed mode in a Node B.- Measurements on Dedicated Resources. This function allows the CRNC to initiate measurements in the Node B. The function also allows the Node B to report the result of the measurements.- DL Power Drifting Correction [FDD]. This function allows the CRNC to adjust the DL power level of one or more Radio Links in order to avoid DL power drifting between the Radio Links.- Reporting of General Error Situations. This function allows reporting of general error situations, for which function specific error messages have not been defined.- Physical Shared Channel Management [TDD]. This function allows the CRNC to manage physical resources in the Node B belonging toShared Channels (USCH/DSCH).- DL Power Timeslot Correction [TDD]. This function enables the Node B to apply an individual offset to the transmission power in each timeslot according to the downlink interference level at the UE.""


ATM resource management (Iub)

RNC BS

AT

M lo

gic

al in

terfa

ce

VP

Ltp

,V

PL

tp,

VC

Ltp

AT

M lo

gic

al in

terfa

ce

VP

Ltp

,V

PL

tp,

3

1

42

Access profile of ATM interface- max bandwidth- max VPI/VCI bits- max VPC/VCC

- VPI- VPL service level: VP/VC- usage e.g. MTP3SL, AAL2UD, IPOAM, AAL2SL, DNBAP, CNBAP- service category: CBR/UBR- traffic and QoS parameters

- interface id- UNI / NNI- IMAGR /PET /SET

- VCI- service category- traffic and QoS parameters

O&M traffic (UBR, IPOAM)

Signalling and user traffic (CBR, AA2SL, DNBAP, CNBAP, AAL2UD)

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

VC

Ltp

Common NBAP signalling

Dedicated NBAP signalling

Dedicated NBAP signalling

SAAL UNI (AAL2) signalling

SAAL UNI (AAL2) signalling

User traffic

User traffic

User traffic

VC

Ltp

VC

Ltp

VP

Ltp

,

User traffic

WAM

WAM


Iur interface (RNSAP)DRNCSRNC


ATM ATM

AAL5

RNSAP RNSAP


AAL5

Iur RNSAP protocol functionsRNSAP protocol functions

Some examples:

• Radio link management and supervision

• Physical channel reconfiguration

• Measurements, dedicated resources

From the specifications Rel 99; 25.423:

""The RNSAP protocol provides the following functions:

- Radio Link Management. This function allows the SRNC to manage radio links using dedicated resources in a DRNS; - Physical Channel Reconfiguration. This function allows the DRNC to reallocate the physical channel resources for a Radio Link;- Radio Link Supervision. This function allows the DRNC to report failures and restorations of a Radio Link;- Compressed Mode Control [FDD]. This function allows the SRNC to control the usage of compressed mode within a DRNS;- Measurements on Dedicated Resources. This function allows the SRNC to initiate measurements on dedicated resources in the DRNS. The function also allows the DRNC to report the result of the measurements;- DL Power Drifting Correction [FDD]. This function allows the SRNC to adjust the DL power level of one or more Radio Links in order to avoid DL power drifting between the Radio Links;- CCCH Signalling Transfer. This function allows the SRNC and DRNC to pass information between the UE and the SRNC on a CCCH controlled by the DRNS;- Paging. This function allows the SRNC to page a UE in a URA or a cell in the DRNS;- Common Transport Channel Resources Management. This function allows the SRNC to utilise Common Transport Channel Resources within the DRNS (excluding DSCH resources for FDD);- Relocation Execution. This function allows the SRNC to finalise a Relocation previously prepared via other interfaces;- Reporting of General Error Situations. This function allows reporting of general error situations, for which function specific error messages have not been defined.- DL Power Timeslot Correction [TDD]. This function enables the DRNS to apply an individual offset to the transmission power in each timeslot according to the downlink interference level at the UE.""


Signalling example: Radio link setup

RACH-Short Initial Access RRC Connection Request

Radio Link Setup

RRC Conn. Request AckFACH - Access Granted

Radio Link Setup Response

Synchronisation IndicatedUL DPCCH

4

DRNC SRNCBSUu Iub Iur

Radio Link Setup Response

Radio Link Setup


Iu interface (RANAP)

Core NetworkDomains

RNC


ATM ATM

AAL5

RANAP RANAP


AAL5

IuRANAP protocol functionsRANAP protocol functions

Some examples:

• RAB management

• Controlling overload in Iu

• Paging users

• Controlling security in UTRAN

• Location reporting/control

From the Specs, Rel'99, 25.413: ""RANAP protocol has the following functions:

- Relocating serving RNC. This function enables to change the serving RNC functionality as well as the related Iu resources (RAB(s) and Signalling connection) from one RNC to another.- Overall RAB management. This function is responsible for setting up, modifying and releasing RABs.- Queuing the setup of RAB. The purpose of this function is to allow placing some requested RABs into a queue, and indicate the peer entity about the queuing.- Requesting RAB release. While the overall RAB management is a function of the CN, the RNC has the capability to request the release of RAB.- Release of all Iu connection resources. This function is used to explicitly release all resources related to one Iu connection.- Requesting the release of all Iu connection resources. While the Iu release is managed from the CN, the RNC has the capability to request the release of all Iu connection resources from the corresponding Iu connection.- SRNS context forwarding function. This function is responsible for transferring SRNS context from the RNC to the CN for intersystem forward handover in case of packet forwarding.- Controlling overload in the Iu interface. This function allows adjusting the load in the Iu interface.- Resetting the Iu. This function is used for resetting an Iu interface.- Sending the UE Common ID (permanent NAS UE identity) to the RNC. This function makes the RNC aware of the UE's Common ID.- Paging the user. This function provides the CN for capability to page the UE.- Controlling the tracing of the UE activity. This function allows setting the trace mode for a given UE. This function also allows the deactivation of a previously established trace.- Transport of NAS (non-access stratum )information between UE and CN (ref. [8]). This function has two sub-classes: 1. Transport of the initial NAS signalling message from the UE to CN. This function transfers transparently the NAS information. As a consequence also the Iu signalling connection is set up.2. Transport of NAS signalling messages between UE and CN, This function transfers transparently the NAS signalling messages on the existing Iu signalling connection. It also includes a specific service to handle signalling messages differently.- Controlling the security mode in the UTRAN. This function is used to send the security keys (ciphering and integrity protection) to the UTRAN, and setting the operation mode for security functions.- Controlling location reporting. This function allows the CN to operate the mode in which the UTRAN reports the location of the UE.- Location reporting. This function is used for transferring the actual location information from RNC to the CN.- Data volume reporting function. This function is responsible for reporting unsuccessfully transmitted DL data volume over UTRAN for specific RABs.- Reporting general error situations. This function allows reporting of general error situations, for which function specific error messages have not been defined.""


The path of the bearer through the network

IuCN Circuit Domain: - RT Traffic - Constant Bit Rates

CN Packet Domain: - NRT Traffic (RT Traffic) - Variable Bit Rates

RAB4


Radio Access Bearer assignment

RAB Assignment Complete

RAB Assignment Request

4

RNCBSUu Iub Iu Core Network

Domains

RAB is configured to be used over the existing Radio Link(s)

Core Network always initiate RAB


Serving RNC Relocation

IuIur Iu

Relocation Required

Relocation Command

SRNC Relocation Commit

Relocation Detect

Relocation Complete

Relocation Request

Reloc. Req. Ack.

Relocation Detect

Relocation Complete

Core NetworkDomain(s)

SourceServingRNC

TargetServingRNC

RAB(s) Assigned

RAB(s) Released

Iu Release

To the target RNC withRNSAP:


Core network MAP (optional topic)

MSC VLR

A(u)C EIRHLR

MAP-B

MA

P-C M

AP-D

MAP-G

MA

P-F

MAP-E To/from other MSC

To/from other VLR

L1L2

L3

SCCP

TCAP

MAP

CCS7 Protocol Stackwithin Circuit SwitchedCore Network Branch:

MTP


Packet switched interfaces (optional topic)

3G RAN

Interface Legend:UuIuGcGfGiGnGr

= Interface between UE (User Equipment) and RAN= Interface between RAN and CN= G interface between Gateway GSN and HLR= G interface between Serving GSN and EIR= G interface between Gateway GSN and IP network= G interface between Serving and Gateway GSN= G interface between Serving GSN and HLR

IP Network(s)


User plane (≈≈≈≈ Application Stratum)

• Signalling between the UE and the destination (for instance an application server).

• In the Uu interface, user plane is DPDCH plus the data it carries.

• User planes for other interfaces are shown in the following fourfigures.

BS RNCMTUSIM

Access Stratum

Serving Stratum

Application Stratum


User plane in the Iub interface

RNCBS


ATM ATM

AAL2

Frame Protocols for:

DCH, RACH and FACH

Frame Protocols for:

DCH, RACH and FACH

AAL2

Iub


User plane in the Iur interface

DRNCSRNC


ATM ATM

AAL2

Frame Protocols forDCH and CCH

Frame Protocols forDCH and CCH

AAL2

Iur


User data on the Iu-CS interface

Core Network

Circuit Switched Domain

RNC


ATM ATM

AAL2

User Data Streams User Data Streams

AAL2

Iu-CS


User data on the Iu-PS interface

Core Network

Packet Switched Domain

RNC


ATM ATM

AAL5

IP

UDP

GTP

User Data Streams

IP

UDP

GTP

User Data Streams

AAL5

Iu-PS


IP/UDP relationship (optional topic)

Network Layers

(OSI 1 - 3)

Transport Layer

Session Layer

Presentation Layer

Application Layer

IP

UDP

GTP

Selected applications for selected purposes


IP/TCP relationship (optional topic)

Network Layers

(OSI 1 - 3)

Transport Layer

Session Layer

Presentation Layer

Application Layer

IP

TCP

Telnet FTP SMTP IMAPHTTP


Summary of UMTS signalling and interfaces

The next two slides summarise the implementation of different interfaces with respect to:

• RAN interfaces

• Core network interfaces


RAN interfaces

BS Functions:- Modulation- Rate Matching- Error Protection in Uu Interface- Uu Interface Channelisation- Macro Diversity (Softer Handover)

Uu Interface:Transport Plane

Control Plane

User Plane

Procedures

- WCDMA (Wideband CodeDivision Multiple Access)

- DPDCH and DPCCH Channels

- Optimised, application-relatedprotocols suitable for bothpacket and circuit switchedtraffic

- Radio Link (RL) Setup- RL Reconfiguration- RL Addition- RL Deletion- Radio Access Bearer Mgmt

Iub Interface:Transport Plane

Control Plane

User Plane

Procedures

- ATM

- Communication Control Ports- Node B Control Ports

- RACH/FACH/DCH Data Portsforming UE Context(s)

- Radio Link (RL) Setup- RL Reconfiguration- RL Addition- RL Deletion- Power Control Information- Handover Signalling- Measurement Reports

Iur Interface:Transport Plane

Control Plane

User Plane

Procedures

- ATM

- SCCP over CCS7

- Frame Protocols for DedicatedChannels over ATM

- Radio Link (RL) Setup- RL Reconfiguration- RL Addition- RL Deletion- Power Control Information- Handover Signalling- Measurement Reports

Iu Interface for CN Packet Domain:Transport Plane

Control Plane

User Plane

Procedures

- ATM

- RANAP over CCS7 or IP

- GTP (GPRS TunnellingProtocol) over UDP/IPover AAL5

- Radio Access Bearer Management- SRNC Relocation- Direct Transfer Procedures(Direct Signalling between UEand the CN Packet Domain)

Iu Interface for CN Circuit Domain:Transport Plane

Control Plane

User Plane

Procedures

- ATM

- RANAP over CCS7

- Optimised, application-relatedprotocols over ATM AAL2

- Radio Access Bearer Management- SRNC Relocation- Direct Transfer Procedures(Direct Signalling between UEand the CN Circuit Domain)

4

BS

BS RNC

RNC

RNC Functions:Radio Resource Management

Telecommunication Management

- Admission Control- Code Allocation- Load Control- Power Control- Handover Control (HO)- Macro Diversity (Soft HO)

- Radio Access Bearer (RAB)- RAB - Radio Link Mapping


Core networkinterfaces

HLR&AC&EIR

MSC&VLR GMSC (&VLR)

Iu PSTN

Gi

3G RAN

Iu Interface for CN Packet Domain:Transport Plane

Control Plane

User Plane

Procedures

- ATM

- RANAP over CCS7 or IP

- GTP (GPRS TunnellingProtocol) over UDP/IPover AAL5

- Radio Access Bearer Management- SRNC Relocation- Direct Transfer Procedures(Direct Signalling between UEand the CN Packet Domain)

Iu Interface for CN Circuit Domain:Transport Plane

Control Plane

User Plane

Procedures

- ATM

- RANAP over CCS7

- Optimised, application-relatedprotocols over ATM AAL2

- Radio Access Bearer Management- SRNC Relocation- Direct Transfer Procedures(Direct Signalling between UEand the CN Circuit Domain)

VLR - VLR MM:Transport Plane

Control Plane

User Plane

Procedures

- CCS7

- CCS7 MTP,SCCP and MAP

- Security ParameterTransfer

MSC - MSC Traffic & MM:Transport Plane

Control Plane

User Plane

Procedures

- CCS7

- CCS7 MTP & ISUPand MAP for MM

- Traffic Path Setup (ISUP)- MSC-MSC Handover (MAP)

MSC/VLR - HLR MM:Transport Plane

Control Plane

User Plane

Procedures

- CCS7

- CCS7 MTP,SCCP and MAP

- Location Enquiry- Roaming Nbr Allocation- Location Registration- Security Parameter Alloc.

SGSN - GGSN:Transport Plane

Control Plane

User Plane

- ATM

- IP (GTP)

- IP

GGSN - Public IP:Transport Plane

Control Plane

User Plane

- ATM

- IP

CN Service Domain:Transport Plane

Control Plane

User Plane

- CCS7

- CCS7, MTP,SCCP, MAP,INAP, CAMEL


3G/UMTS Signalling and Interfaces

Review Questions


Review (1/7)

PCM

ISUP

ATM

RANAP over CCS7

Iu-PS

RANAP over CCS7,(later also over IP)

ATM

RNSAP

Iub

ATM

NBAP

MSC

TCSM

RAN

Mobility Core

BSCMSC

ATM

Module

2G

SGSN

3G

SGSN

RNC

RNC

Gb

Abis HLR

ControlTransportInterface

PCM

LapD

A


PCM

BSSAP

ControlTransport

Iu-CS



ATM/IP

Iur



GSMBTS

WCDMABTS

PSTN


Review (1/7)MSC

TCSM

RAN

Mobility Core

BSCMSC

ATM

Module

2G

SGSN

3G

SGSN

RNC

RNC

Gb

Abis HLR


PCM

LapD

A


PCM

BSSAP

ControlTransport

Iu-CS



ATM

Iur



GSMBTS

WCDMABTS

PSTN


Review (2/7)

2. Which of the following sentences about the Radio Access Bearer is true?

a. The RAB carries a connection between the terminal and the corenetwork.

b. The RAB is a radio link signalling protocol.c. Voice is the only information on a RAB.d. All of the above.

3. Which of the following sentences about the RRC is true?

a. The RRC is the connection between the terminal and the core network,upon which traffic is transferred.

b. The RRC is the connection between the terminal and RAN andcontains the RABs.

c. The RRC is the connection between the RAN and core network andcontains all the RABs from different terminals.


Review (3/7)

4. Which of the following sentences about the ATM connection is correct?

a. The virtual channels contain virtual paths for the data.b. There is one virtual path per virtual channel.c. One virtual circuit contains at the most one virtual channel.d. One virtual path can contain many virtual channels.

5. In the RNC, what is the function of the MAC (Medium Access Control)?

a. Selection of data to be inserted in Radio Frame.b. Selection of common channels.c. Multiplexing of logical channels to transportation channels.d. Ciphering for real-time traffic.e. All of the above.


Review (4/7)

6. Which of the following sentences best describes the function and role of the NBAP protocol?

a. It is the protocol used between the network and the PSTN and usedfor call set-up purposes.

b. It is the protocol used between two RNCs. It is used when one RNCneeds to signal a cell in an URA and when performing softhandovers.

c. It is the protocol used between the core network and the RNC andused for the management of resources.

d. It is the protocol used between the RNC and the BTS and used tocontrol the allocation of resources.


Review (5/7)

7. Which of the following sentences best describes the function and role of the RANAP protocol?

a. It is the protocol used between the network and the PSTN andused for call set-up purposes.

b. It is the protocol used between two RNCs and used when oneRNC needs to signal a cell in an URA and performing softhandovers.

c. It is the protocol used between the core network and the RNCand used for the management of resources.

d. It is the protocol used between the RNC and the BTS and usedto control the allocation of resources.


Review (6/7)8. Which of the following sentences best describes the function and role of

the RNSAP protocol?

a. It is the protocol used between the network and the PSTN and used forcall set-up purposes.

b. It is the protocol used between two RNCs. It is used when one RNCneeds to signal a cell in an URA and when performing soft handovers.

c. It is the protocol used between the core network and the RNC and usedfor the management of resources.

d. It is the protocol used between the RNC and the BTS and used to controlthe allocation of resources.


Review (7/7)

9. Which of the following sentences best describes the function and role of the ISUP protocol?

a. It is the protocol used between the network and the PSTN and usedfor call set-up purposes.

b. It is the protocol used between two RNCs. It is used when one RNCneeds to signal a cell in a URA and when performing softhandovers.

c. It is the protocol used between the core network and the RNC andused for the management of resources.

d. It is the protocol used between the RNC and the BTS and used tocontrol the allocation of resources.

05 - Introduction to UMTS Signalling and Interface2_emad

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