interfaces and protocols introduction

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WR_005_E1

Call and Signaling Process

Interfaces and protocolsV0507

ZTE University

3G Course Team


Course Objectives

Understand ATM basic knowledge

Master Network interfaces

Master signaling process


Agenda:

ATM Basics

Network Interfaces

Software workflow


5bytescell-header

48 bytespayload

(user information)

ATM cell

53 bytes

ATM-Asynchronous Transfer Mode

ATM transfers information in fixed-size units called cells.

Each cell consists of 53 bytes.

ATM (1)


ATM (2)

Circuit Switch

Fix connecting, synchronization time division

multiplexing

Good real time performance and weak flexibility

Packet Switch

Virtual circuit connecting without fixed time slot

Weak real time performance and good flexibility


ATM protocol reference model

Layer m

anagem

ent

Pl ane managem

ent

Control plane User plane

Management plane

Higher layer protocol

AAL adaptation layer

ATM cell layer

PHY physical layer

Higher layer protocol


ATM protocol reference model(1)

ATM protocol reference model consists of three planes: User plane

responsible for user information transmission hierarchically. Control plane

provides the call and connection control function and the signaling function is also involved, which is hierarchy too.

Management plane

provides two management functions: plane management and layer management.

The plane management is responsible for management related to the entire system and performs the function of coordination among different planes.

While the layer management is responsible for management of network resources and protocol parameters as well as processes the operation & maintenance information flow at each layer.


ATM protocol reference model(2)

The ATM protocol reference model consists of four layers:

Physical layer

responsible for correct and effective cell transmission via the

physical media

ATM layer

responsible for cell switching, routing and multiplexing

ATM adaptation layer

the AAL layer is responsible for adaptation of higher-layer service

information or signaling information to ATM cell flow

Higher layer

equivalent to the application layer of each service or the higher

layer of signaling.


Comparison between VCC and VPC

The connection-oriented mode is adopted in ATM.

ATM connection, that is, end-to-end transfer capability

Virtual channel (VC) level -VCC

Virtual path (VP) level-VPC

VCC

Virtual channel level

Virtual path level

VC link

VP link

VPC

VCIx VCIy VCIz

VPIx VPIy VPIz

VCC end point VCC end point

VPC end point VPC end point

VC link VC link

VP link VP link


VP & VC Switching

The VPI value has to be changed during VP switching While all VCI

values contained in it remain unchanged.

During VC switching, both the VPI and VCI values should be changed.

VP exchange

VC exchange

VP end point

VCI 1 VCI 3

VCI 4

VCI 2

VPI 2

VPI 3

VCI 4

VCI 3

VPI 5VCI 1

VCI 2VPI 4

VPI 1VCI 1

VCI 2

VCI 1

VCI 2


ATM Adaptation layer

AAL between ATM layer and high-layer applications

implements the service functions needed by the high layer

(such as error checking processing and timing control),

supports the adaptation between the high layer and

ATM layer-mapping PDU of the high layer to the

information segment of the ATM cell or vice versa.


Traffic

ParameterClass A Class B Class C Class D

Timing between source and destination

need Not need

Bit rate fixed various

Connection mode Connection-orient Connectionless- orient

AAL 3 AAL 4AAL types AAL 1 AAL 2

AAL 5

Traffic sample Circuit simulation

Moving image video and audio

Connection-orient data transmitting

connectionless data transmitting

QoS QoS1 QoS2 QoS3 QoS4

AAL classes


AAL2

AAL2

suitable for VBR (variable bit rate) traffic, typically

includes services characterized as voice or video.

Traffic must be real-time transmitted for existing timing

relationship between signal source and signal

destination.

Allowing the same VCC multiplexing multiple

connection procession.


AAL5

AAL5

Efficient Data traffic transmitting adaptation pr

otocol

Supplying the same traffic with AAL3/4

Can be used as signal AAL.


Agenda

ATM Basics

Network Interfaces

Software workflow


UTRAN Architecture


Network Interfaces

Universal Model of the UTRAN Interface:

ApplicationProtocol

DataStream(s)

ALCAP(s)

TransportNetwork

Layer

Physical Layer

SignallingBearer(s)

TransportUser

NetworkPlane

Control Plane User Plane

TransportUser

NetworkPlane

Transport NetworkControl Plane

Radio

Network

Layer

SignallingBearer(s)

DataBearer(s)


Iu Interface

According to different connected entities, the Iu

interface can be divided into three types:

Iu-CS (Iu Circuit Switched)

Iu-CS is the interface for connection with the circuit-switched (CS)

CN.

Iu-PS (Iu Packet Switched)

Iu-PS is the interface for connection with the packet-switched (PS)

CN.

Iu-BC (Iu Broadcast)

Iu-BC is the interface for connection with the broadcast domain of C

N. Iu-BC supports the cell broadcast service and is used to connect

UTRAN with the CN’s broadcast domain.


Iu Interface

Node B

RNC

RNC

CS

Domain

PS

Domain

BC

Domain

Node B

Node B

Node B

UTRAN Core Network (CN)

“Iu-CS”

“Iu-PS”

“Iu-BC”

Iu Interface


Iu-CS Interface Stack Structure

Q.2150.1

Q.2630.1

RANAP Iu UP ProtocolLayer

TransportNetwork

Layer

Physical Layer

TransportUser

NetworkPlane


TransportUser

NetworkPlane


RadioNetwork

Layer

ATM

SSCOPAAL5

SSCOPSSCF-NNI

AAL2AAL5

MTP3bMTP3bSCCP

SSCF-NNI


Iu-PS Interface Stack Structure

SSCF-NNI

SSCOP

AAL5

IP

SCTP

SCCP

SSCF-NNI

M3UA

RANAPIu UP Protocol

Layer

TransportNetworkLayer

Physical Layer

TransportUser

NetworkPlane


TransportUser

NetworkPlane


RadioNetwork

Layer

ATM

AAL5

IP

UDP

GTP-U

Physical Layer

ATM

MTP3-B


Iur interface Functions

Iur interface has the following functions:

Inter-RNC mobility management

SRNC relocation, inter-RNC cell and UTRAN registration area upda

te, inter-RNC paging, and protocol error report.

Dedicated channel data transmission

used to transmit dedicated channel data between two RNCs.

The specific functions of the transmission are:

Common channel data transmission

setup and release of the transmission connection needed in commo

n channel data stream transmission of the Iur interface,

Global resource management

transmission of inter-RNC cell measurement information,

transmission of inter-RNC Node B timing information.


Iur Interface Stack Structure

SCTP

AAL5

SSCF-NNI

SSCOP

MTP3B

IP

SCCP

AAL5

ALCAP Q.2630.1

STC Q.2150.1

RNSAP Iur Data

Str eam(s)

TransportNetwork

Layer

Physical Layer

TransportUser

NetworkPlane


TransportUser

NetworkPlane


RadioNetwork

Layer

ATM

AAL2

SCTPSSCF -NN

ISSCF-NNI

SSCOP

MTP3B

IP

M3UA M3UA


RNSAP, Radio Network Subsystem AP

RNSAP provides control signaling exchange over the Iur interface.

responsible for bearer management signaling between two RNCs.

SRNC utilized for setting up and controlling radio links using dedicated resources in D

RNCs.

One signaling connection per DRNC.

Transfers

Radio and mobility control signaling including measurement information needed for handov

ers, synchronizations and radio resource control between RNSs

Relays Iub/Iur DCH, DSCH, RACH/CPCH and FACH transport channel data streams.


Iub interface Functions

Management of the Iub interface transmission resources. Logic operation maintenance of Node B, including:

the cell configuration management

radio network performance measurement

resource event management

common transmission channel management

radio resource management Transmission of application-related operation & maintenance information. System information management. Common channel traffic management, dedicated channel traffic

management and shared channel management. Timing and synchronization management, including:

node synchronization

transmission channel synchronization between the RNC and Node B

and node synchronization between Node Bs


Iub Interface Stack Structure

Node BApplication Part

(NBAP)

AAL Type 2

ALCAP

TransportLayer

Physical Layer

RadioNetwor

kLayer

Radio NetworkControl Plane

TransportNetwork

Control Plane

DC

H F

P

RA

CH

FP

ATM

DS

CH

FP

AAL Type 5

User Plane

SSCF-UNI

SSCOP

AAL Type 5

SSCF-UNI

SSCOP

Q.2630.1

Q.2150.2

FA

CH

FP

PC

H F

P

US

CH

FP

CP

CH

FP


NBAP, Node-B Application Part

NBAP provides control signaling exchange over the Iub interfac

e between base station and its controlling RNC.

All Resources of a base station are controlled by its controlling

RNC. Hence, all the physical resources of a Node-B appear as l

ogical resources for RNC through Iub interface.

Several signaling links over the Iub interface can be related t

o a dedicated NBAP.


NBAP, Node-B Application Part

Common NBAP procedures are related to the whole cell:

O&M actions (Cell configuration)

Broadcast channels (Common signaling)

Random access channels

Setting up new dedicated link

Handling of cell-wise measurements

Error recovery Dedicated NBAP procedures are related to one specific UE:

Radio link management of dedicated and shared channels

Softer combining (Combining the signals received from different sectors of the cell)

Link measurements

Downlink power control activities.

Link fault recovery


Uu Interface Stack Structure

L3

cont

ro

lcont

rol

cont

rol

cont

rol

LogicalChannels

TransportChannels

C-planesignalling

U-planeinformation

PHY

L2/MAC

L1

RLC

DC

Nt

GC

L2/RLC

MAC

RLCRLC

RLCRLC

RLCRLCRLC

Duplicationavoidance

UuSboundary

BMC L2/ BMC

control

PDCPPDCP L2/PDCP

DC

Nt

GC

RadioBearers

RRC


Uu Interface Stack Structure(1)

Physical Layer Protocol

provides the MAC sublayer with transmission channel services. MAC Protocol (Media Access Control)

provides the RLC sublayer with logic channel services. RLC Protocol (Radio Link Control)

on the control plane, provides the RRC sublayer with signaling radio bearer services.

on the user plane, provides service radio bearer services together with the PDCP sublayer.

PDCP (Packet data convergence protocol)

adapt different types of network layer protocols to the radio interface.

only exists in the packet domain BMC (Broadcast main control)

transfer broadcast and multicast information over the radio interface.


Uu Interface Stack Structure(2)

RRC (Radio resource control)

provide services for the non-access layer, for example, transmitting messages like call control, session management and mobility management at the control interface after encapsulating them.

provides control and management the protocol at each lower layer.

setup, maintenance and release of an RRC connection between UE and UTRAN

setup, reconfiguration and release of radio bearer

distribution, reconfiguration and release of radio resources used in the RRC connection

RRC connection’s mobility function management

routing for the higher-layer PDU

request for QoS control

UE measurement report and report control,

outer loop power control, ciphering control, paging

initial cell selection and reselection in the idle mode

RRC message completeness protection.


Appendix

Abbreviation Full Name

SCCP Signaling connection control protocol

MTP3B Broadband message transfer protocol

SSCF-NNI Service specific coordination function for support of signaling

at the network node interface

SSCF-UNI Service specific coordination function for support of signaling

at the user network interface

SSCOP Service specific connection oriented protocol

Q.2630.1 AAL2 signaling control protocol

Q.2150.1 AAL2 signaling transport converter at NNI

M3UA MTP3 user adaptation protocol

SCTP Stream control transmission protocol

GTP-U GPRS tunneling protocol – user


Agenda

ATM Basics

Network Interfaces

Software workflow


Radio Network c-plane protocol

RNC

CN

Node B

UE RNC

RANAP

RNSAP

NBAP

RRC

NBAP： Node B Application Part

RANAP: Radio Access Network Application Part

RNSAP: Radio Network Subsystem Application Part

RRC: Radio Resource Control


NBAP

L1 L1

MAC

RLC

RRC

MM/GMM

CC SM

NBAP

Transport Layer

Transport

Layer

Transport

LayerMAC

RLC

RRC RANAP RANAP

MM/GMM

CC SM

Uu

UE Node B RNC CN

Iub Iu

…Transport

Layer

UTRAN Control Plane Protocol Stack


L1

MAC

RLC

PDCP

Transport

Layer

Transport

Layer

Iu UP

Uu

UE Node B RNC CN

Iub Iu

L1 FP FPTransport Layer

MAC

RLC

PDCP

Iu UPUser data

Transport Layer

UTRAN User Plane Protocol Stack


Basic Conception (1)

RRC (Radio Resource Control)

provides information transfer service to the NAS (Non Access

Stratum).

responsible for controlling the configuration of UMTS radio interface

Layers 1 and 2.

RRC Connection

A point to point bi directional connection between the RRC (Radio

Resource Control) entities on the UE (User Equipment) and

UTRAN (UMTS Terrestrial Radio Access Network).

The UE requires an RRC connection to access the services of the

UMTS network.



RAB -Radio Access Bearer

identify the service the AS (Access Stratum) provides

to the NAS (Non Access Stratum) for transfer of user

data between the UE (User Equipment) and the CN

(Core Network).

RB -Radio Bearer

The service provided by the Layer 2 for the transfer of

user data between UE (User Equipment) and UTRAN

(UMTS Terrestrial Radio Access Network).



RL (Radio Link)

RL is a logical association between single UE (User

Equipment) and a single UTRAN (UMTS Terrestrial

Radio Access Network) access point.

Its physical realization comprises one or more radio

bearer transmissions.

It is possible for a UMTS mobile to have many radio

links established, when this occurs the mobile is said to

be in a soft handover.


UE Node B RNC

RRC RRC1.CCCH: RRC Connection Request

Allocate RNTSelect L1

and L2 parameters

NBAP NBAP2.Radio Link Setup Request

Start RX

NBAP NBAP3.Radio Link Setup Response

ALCAP Iub Data Transport Bearer Setup

DCH-FP DCH-FP4.Downlink Synchronisation

DCH-FP DCH-FP5.Uplink Synchronisation

Start TX

RRC RRC6.CCCH: : RRC Connection Setup

RRC RRC7.DCCH: : RRC Connection Setup Complete

RRC setup


RAB setup

UE SRNCNode B CN

RAB ASSIGNMENT REQUEST

ALCAP setup

RL CONFIG PRE

RL CONFIG READY

ALCAP setup, synchronization

RRC RB SETUP

RRC RB SETUP COMPLETERAB ASSIGNMENT RESPONSE

RL CONFIG COMMIT


Call Setup Flow

UE Node B RNC CN

RRC connection setup request

RRC connection setup

RAB assignment requestRL setup request

RL setup response

RB setup

RB setup completion

Paging (RANAP)Paging (RRC)

NAS message interaction (service request)

RAB assignment response


Call Setup Flow（ 1）

The flow is as follows:

The CN initiates a paging message to the RNC according to information like the

location of the called UE.

The RNC judges the paging message from the CN and then sends a paging message

to the corresponding UE.

If no RRC connection is available before the service starts, the UE will send a RRC

connection setup request message (RRC Connection Request) to the RNC to request

setup of a RRC connection.

The RNC determines to set up a RRC connection according to the setup reason and

the system resource occupation. After allocating RNTI and resources related to L1 and

L2, it sends a RRC connection setup message (RRC Connection Setup) to the UE.

After signaling connection setup, the higher layer of the UE (NAS) sends a service

request message to the CN through a directly transmitted message.

The CN sends a RAB assignment message (RAB Assignment Request) to the RNC.


Call Setup Flow（ 2）

According to the parameters carried in the RAB assignment message sent from the CN, the RNC sends a radio link setup message (Radio Link Setup Request) to an appropriate Node B.

After allocating the corresponding resources, the corresponding Node B sends a radio link setup response (Radio Link Setup Response) to the RNC to notify the RNC of the information that the radio link setup has been finished.

The RNC sends a radio bearer setup message (Radio Bearer Setup) to the UE.

After executing RB setup, the UE sends a radio bearer setup completion message (Radio Bearer Setup Complete) to the RNC.

After receiving the RB setup completion message, the RNC sends a RAB assignment response message (RAB Assignment Response) to the CN to end the RAB setup flow. Up to now, the entire call process is finished.

Note: No paging process is involved for call setup requests actively initiated by UEs. In such cases, the call process will directly start from Step 3.


Soft Handover Flow

UE NodeB（DRNS) DRNCNodeB

(SRNS)Measurement

report

RL creation requestRL setup request

Active set update command

SRNC

RL setup response RL setup response

Active set update completion

RL release requestRL releasecompletion

A

B


Hard Handover Flow

UETarget Node

B SRNCOriginalNodeB

Measurement report

RL setup request

Reconfiguration command

RL setup response

Reconfiguration completion

RL deletion request

RL deletion response


Call setup flow (1)


Call setup flow (2)


Call setup flow (3)


Call setup flow (4)


Call setup flow (5)


Call setup flow (6)


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