RADIO ACCESS NETWORK ARCHITECTURE

5.1 System Architecture5.2 UTRAN Architecture5.3 General Protocol Model for UTRAN

Terrestrial Interfaces5.4 Iu, The UTRAN–CN Interface5.5 UTRAN Internal Interfaces5.6 UTRAN Enhancements and Evolution5.7 UTRAN CN Architecture and Evolution

5.1 SYSTEM ARCHITECTURE Functional network elements

User Equipment (UE) interfaces with user and radio interface

Radio Access Network (RAN, UMTS Terrestrial RAN = UTRAN)handles all radio-related functionality

Core Networkswitches and routes calls and data connections to external networks

PLMN (Public Land Mobile Network) operated by a single operator distinguished from each other with unique

identities operational either on their own or together with

other sub-networks connected to other PLMNs as well as to other

types of network, such as ISDN, PSTN, the Internet, etc.

UE consists of two parts Mobile Equipment (ME)

the radio terminal used for radio communication over Uu interface

UMTS Subscriber Identity Module (USIM)a smartcard that holds the subscriber identityperforms authentication algorithmsstores authentication and encryption keyssome subscription information that is needed at the terminal

UTRAN consists of two elements Node B

converts data flow between Iub and Uu interfaces

participates in radio resource management Radio Network Controller (RNC)

owns and controls radio resources in its domain the service access point (SAP) for all services that UTRAN provides the CNe.g., management of connections to UE

Main elements of CNa) HLR (Home Location Register)b) MSC/VLR (Mobile Services Switching Centre/Visitor

Location Register)c) GMSC (Gateway MSC)d) SGSN (Serving GPRS (General Packet Radio Service)

Support Node)e) GGSN (Gateway GPRS Support Node)

(a) HLR (Home Location Register) a database located in user’s home system that

stores the master copy of user’s service profile service profile consists of, e.g.,

information on allowed services, forbidden roaming areas

supplementary service information such as status of call forwarding and the call forwarding number

it is created when a new user subscribes to the system, and remains stored as long as the subscription is active

for the purpose of routing incoming transactions to UE (e.g. calls or short messages)HLR also stores the UE location on the level of MSC/VLR and/or SGSN

(b) MSC/VLR (Mobile Services Switching Centre/Visitor Location Register)◦ the switch (MSC) and database (VLR) that serve

the UE in its current location for Circuit Switched (CS) services

◦ the part of the network that is accessed via MSC/VLR is often referred to as CS domain

◦ MSC used to switch CS transactions

◦ VLR holds a copy of the visiting user’s service profile, as well as more precise information on the UE’s location within the serving system

(c) GMSC (Gateway MSC) the switch at the point where UMTS PLMN is

connected to external CS networks all incoming and outgoing CS connections go

through GMSC

(d) SGSN (Serving GPRS (General Packet Radio Service) Support Node) functionality is similar to that of MSC/VLR but is

typically used for Packet Switched (PS) services the part of the network that is accessed via

SGSN is often referred to as PS domain

(e) GGSN (Gateway GPRS Support Node) functionality is close to that of GMSC but is in

relation to PS services

External networks can be divided into two groups CS networks

provide circuit-switched connections, like the existing telephony service

ISDN and PSTN are examples of CS networks PS networks

provide connections for packet data services Internet is one example of a PS network

Main open interfaces Cu interface

the electrical interface between USIM smartcard and ME

Uu interfacethe WCDMA radio interfacethe interface through which UE accesses the fixed part of the system

the most important open interface in UMTS

Iu interfaceconnects UTRAN to CN

Iur interfaceallows soft handover between RNCs

Iub interfaceconnects a Node B and an RNC

5.2 UTRAN ARCHITECTURE

5.2.1 Radio Network Controller5.2.2 Node B (Base Station)

UTRAN consists of one or more Radio Network Sub-systems

(RNS) RNS

a subnetwork within UTRAN consists of one Radio Network Controller (RNC) and

one or more Node Bs

RNCs may be connected to each other via Iur interface RNCs and Node Bs are connected with Iub interface

Main characteristics of UTRAN support of UTRA and all related functionality

support soft handover and WCDMA-specific Radio Resource Management algorithms

use of ATM transport as the main transport mechanism in UTRAN

use of IP-based transport as the alternative transport mechanism in UTRAN from Release 5 onwards

5.2.1 RADIO NETWORK CONTROLLER

RNC (Radio Network Controller) the network element responsible for radio resources

control of UTRAN it interfaces CN (normally to one MSC and one SGSN) terminates RRC (Radio Resource Control) protocol that

defines the messages and procedures between mobile and UTRAN

it logically corresponds to the GSM BSC

註： RADIO RESOURCE CONTROL

Radio Resource Control (RRC) messages the major part of the control signaling between UE and

UTRAN carry all parameters required to set up, modify and

release Layer 2 and Layer 1 protocol entities The mobility of user equipment in the connected

mode is controlled by RRC signaling measurements, handovers, cell updates, etc.

3GPP BEARERS FOR SUPPORTING PACKET-SWITCHED SERVICES

UTRAN CN

TRAFFIC BEARERS STRUCTURE SUPPORTINGPACKET-SWITCHED SERVICES

3GPP Bearer a dedicated path between mobile and its serving

GGSN for a mobile to send or receive packets over a 3GPP PS

CN a 3GPP Bearer in a UMTS network would be a UMTS

Bearer

Constructed by concatenating Radio Access Bearer (RAB)

connects a mobile over a RAN to the edge of CN (i.e., a SGSN)

CN Bearercarries user traffic between the edge of CN and a GGSN

SIGNALING AND TRAFFIC CONNECTIONS BETWEEN MOBILE

AND SGSN

The signaling connection between mobile and SGSN is constructed by concatenating Signaling Radio Bearer

between mobile and RAN (e.g., the RNC in UTRAN) Iu Signaling Bearer

between RAN and SGSN Signaling and traffic connections between mobile and

SGSN Radio Resource Control (RRC) connection Radio Access Network Application Part (RANAP)

connection

Radio Resource Control (RRC) connection includes Signaling Radio Bearers and Traffic

Radio Bearers for the same mobile used to establish, maintain, and release Radio

Bearers a mobile will use a common RRC connection to

carry signaling and user traffic for both PS and CS services

Radio Access Network Application Part (RANAP) connection includes Iu Signaling Bearers and Iu Traffic

Bearers for the same mobile used to establish, maintain, modify, change, and

release all these Iu Bearers

5.2.1.1 LOGICAL ROLE OF THE RNC

The RNC controlling one Node B is indicated as the Controlling RNC (CRNC) of Node B

Controlling RNC responsible for load and congestion control of its

own cells executes admission control for new radio links

In case one mobile–UTRAN connection uses resources from more than one RNS (due to handover), the RNCs involved have two separate logical roles Serving RNC (SRNC) Drift RNC (DRNC)

Serving RNC SRNC for one mobile is the RNC that terminates

both the Iu link for the transport of user data and the corresponding RANAP (RAN Application Part) signaling to/from the core network

SRNC also terminates the Radio Resource Control Signaling, that is the signaling protocol between the UE and UTRAN

it performs L2 processing of the data to/from the radio interface

basic Radio Resource Management operations are executed in SRNC map Radio Access Bearer (RAB) parameters

into air interface transport channel parameters handover decision outer loop power control

one UE connected to UTRAN has one and only one SRNC

Drift RNC DRNC is any RNC, other than the SRNC, that

controls cells used by the mobile DRNC does not perform L2 processing of the user

plane data, but routes the data transparently between Iub and Iur interfaces

one UE may have zero, one or more DRNCs

5.2.2 NODE B (BASE STATION) Main function of Node B

◦ perform the air interface L1 processing, e.g., channel coding and interleaving rate adaptation spreading

also performs some basic Radio Resource Management operations, e.g. inner loop power control

It logically corresponds to the GSM Base Station

註： INTERLEAVING

The transmission of pulses from two or more digital sources in time-division sequence over a single path

5.3 GENERAL PROTOCOL MODEL FOR UTRAN TERRESTRIAL INTERFACES

5.3.1 General5.3.2 Horizontal Layers5.3.3 Vertical Planes

5.3.1 GENERAL

The general protocol model for UTRAN terrestrial interfaces the layers and planes are logically independent

of each other parts of the protocol structure may be changed

in the future while other parts remain intact

5.3.2 HORIZONTAL LAYERS

The protocol structure consists of two main layers Radio network layer Transport network layer

5.3.3 VERTICAL PLANES

5.3.3.1 Control Plane5.3.3.2 User Plane5.3.3.3 Transport Network Control Plane5.3.3.4 Transport Network User Plane

5.3.3.1 CONTROL PLANE Control Plane

used for all UMTS-specific control signaling includes two parts

application protocol RANAP (RAN application part) in Iu RNSAP (RNS application part) in Iur NBAP (Node B application part) in Iub

signaling bearer transport the application protocol messages

Application protocol is used for setting up bearers to UE, i.e.

radio access bearer in Iu radio link in Iur and Iub

5.3.3.2 USER PLANE

User Plane transport all information sent and received by

the user, such ascoded voice in a voice callpackets in an Internet connection

includes two partsdata stream(s)data bearer(s) for data stream(s)

5.3.3.3 TRANSPORT NETWORK CONTROL PLANE

Used for all control signaling within transport layer Does not include any radio network layer

information Includes ALCAP (Access Link Control Application

Part) protocol used to set up the transport bearers (data bearer) for user plane

Includes signaling bearer needed for ALCAP Transport network control plane

acts between control plane and user plane makes it possible for application protocol in radio

network control plane to be completely independent of the technology selected for data bearer in user plane

5.3.3.4 TRANSPORT NETWORK USER PLANE

Transport Network User Plane data bearer(s) in user plane signaling bearer(s) for application protocol

5.4 IU, THE UTRAN–CN INTERFACE

5.4.1 Protocol Structure for Iu CS5.4.2 Protocol Structure for Iu PS5.4.3 RANAP Protocol5.4.4 Iu User Plane Protocol5.4.5 Protocol Structure of Iu BC, and the SABP

Protocol

Iu interface an open interface that divides the system into

radio-specific UTRAN and CN handles switching, routing and service control

Iu can have two main different instances and one additional instance Iu CS

connect UTRAN to Circuit Switched (CS) CN Iu PS

connect UTRAN to Packet Switched (PS) CN Iu BC (Broadcast)

support Cell Broadcast Services connect UTRAN to the Broadcast domain of CN

5.4.1 PROTOCOL STRUCTURE FOR IU CS

5.4.1.1 Iu CS Control Plane Protocol Stack5.4.1.2 Iu CS Transport Network Control Plane

Protocol Stack5.4.1.3 Iu CS User Plane Protocol Stack

The following figure depicts the Iu CS overall protocol structure the three planes in the Iu interface share a

common ATM (Asynchronous Transfer Mode) transport

physical layer is the interface to physical medium optical fiber radio link copper cable

5.4.1.1 Iu CS CONTROL PLANE PROTOCOL STACK Control Plane protocol stack consists of

RANAP, on top of Broadband (BB) SS7 (Signaling System #7) protocols

The applicable layers areSignaling Connection Control Part (SCCP)Message Transfer Part (MTP3-b)SAAL-NNI (Signaling ATM Adaptation Layer

for Network to Network Interfaces)

註： SS7 MTP (Message Transfer Part，訊息轉送部 )

SS7的第一層為信號數據鏈路層 (Signaling Data Link Level)又稱為實體層 (Physical Level)定義信號鏈路之實體、電氣與功能，以提供實體鏈路收送 SS7信號

SS7的第二層為信號鏈路層 (Signaling Link Level)確保 SS7信號訊息在實體層上收送的可靠度

SS7的第三層為信號網路層 (Signaling Network Level)處理信號訊息及管理信號網路

MTP3-b提供訊息繞送、識別，通訊裝置間的訊號鏈結管理、分享與轉換

SCCP：協助 ISUP做端對端之交換供 ISDN-UP (ISUP)建立端對端的信號接續 (Signaling

Connection)供網管、維護中心與各交換局間 (有 SP功能者 ) 建立信號接續

供將來用戶 (User)(如帳務中心 ) 與各交換局 (SP點 ) 間建立信號接續，可直接傳送帳務資料，而不用再運送磁帶

供將來其他用戶部 (User Part)建立信號接續使用

TCAP交易能力 (Transaction Capabilities； TC)或稱交易能力應用部 (Transaction Capabilities Application Part；TCAP)

在 SS7網路中是屬於應用層 (Application Layer)中的一個應用服務元件 (Application Service Element；ASE)

目的提供 SS7網路中之信號節點對信號節點間非電路接續相關訊息的傳送

為它們之間的各種應用提供一般性服務例如

交換機與交換機間非電路接續相關訊息的交換交換機對網路服務中心資料庫作號碼翻譯 ( 例如

080服務號碼 ) 皆可由 TCAP所提供的服務來達成

SAAL-NNI is further divided into Service Specific Coordination

Function (SSCF) Service Specific Connection

Oriented Protocol (SSCOP) ATM Adaptation Layer 5 (AAL) layers

SSCF and SSCOP layers designed for signaling transport in

ATM networks take care of signaling connection

management AAL5 is used for segmenting the data

to ATM cells

註： SSCF (Service Specific Coordination Function)

為特定服務協調功能包括 UNI (User-to-Network Interface)與 NNI

(Network-to-Network Interface)負責連線管理 (connection management)與鏈結狀態 (link status)等管理

SSCOP (Service Specific Connection Oriented Protocol)為特定服務連結導向通訊協定，提供可靠的訊號傳輸服務

包括流量控制、重送機制、連線控制與錯誤偵測等透過 SSCOP傳送資料，如發生資料內容錯誤，可透過重送機制來修正錯誤；也提供上層通訊協定可靠的傳輸服務

註： ATM IN BRIEF

註： AAL2 AND AAL5

Above the ATM layer we usually find an ATM adaptation layer (AAL)

AAL process the data from higher layers for ATM

transmission segment the data into 48-byte chunks and

reassemble the original data frames on the receiving side

Five different AALs (0, 1, 2, 3/4, and 5) AAL0

no adaptation is needed the other adaptation layers have different

properties based on three parametersreal-time requirementsconstant or variable bit rateconnection-oriented or connectionless data transfer

Iu interface uses two AALs AAL2

主要特色為需要建立連線 (connection-oriented services)、即時傳輸 (real-time data streams)及非固定的傳輸速率 (variable bit rate， VBR)，適合用來傳送經過壓縮的影音資料

每個經過壓縮的影音資料傳輸速率並不固定，會隨著每個畫面的複雜度不同而有所改變，此類服務需要即時性傳輸，適用於 AAL2的傳輸服務

AAL5主要的特色為無需建立連線、非即時傳輸以及非固定的傳輸速率

5.4.1.2 IU CS TRANSPORT NETWORK CONTROL PLANE PROTOCOL STACK

Transport Network Control Plane protocol stack consists of Signaling Protocol on top of BB SS7

protocols for setting up AAL2 connections (Q.2630.1

[Q.aal2 CS1])adaptation layer (Q.2150.1 [AAL2

Signaling Transport Converter for MTP3b])

BB SS7 are those described above without SCCP layer

5.4.1.3 IU CS USER PLANE PROTOCOL STACK

A dedicated AAL2 connection is reserved for each individual CS service

Iu User Plane Protocol residing directly on top of AAL2

5.4.2 PROTOCOL STRUCTURE FOR IU PS

5.4.2.1 Iu PS Control Plane Protocol Stack5.4.2.2 Iu PS Transport Network Control Plane

Protocol Stack5.4.2.3 Iu PS User Plane Protocol Stack

The following figure depicts Iu PS protocol

structurea common ATM transport is

applied for both User Plane and Control Plane

the physical layer is as specified for Iu CS

5.4.2.1 IU PS CONTROL PLANE PROTOCOL STACK Control Plane protocol stack

consists of RANAP signaling bearers

BB SS7-based signaling bearer

an alternative IP-based signaling bearer

SCCP layer is used for both bearer

IP-based signaling bearer consists of M3UA (SS7 MTP3 – User

Adaptation Layer) SCTP (Stream Control

Transmission Protocol) designed for signaling

transport in the Internet ensure reliable, in-sequence

transport of messages with congestion control

IP (Internet Protocol) AAL5 (common to both

alternatives)

註： SCTP (RFC 2960)

提供可靠的傳輸服務，主要存在於IuPS介面

運作於完整的 IP網路環境中，並可適用於 IPv4與 IPv6

提供流量控制、重送機制，以供上層M3UA一個穩定可靠的傳輸介面

M3UA基於 SCTP，提供上層 SCCP訊號傳送機制

SCCP原本以MTP3作為它下層的通訊協定

為順利透過 IP或 ATM等通訊協定，在其下層提供一個類似MTP3的通訊協定，以便順利運作在這些通訊協定上

RANAP本身並無處理錯誤能力它假設所有送出的訊息都會被正確接收，即其下層通訊協定 (Transport Network Layer)需有處理錯誤能力

如 SSCOP與 SCTP具有錯誤偵測與資料重送機制

5.4.2.2 IU PS TRANSPORT NETWORK CONTROL PLANE PROTOCOL STACK

Transport Network Control Plane is not applied to Iu PS

Setting up of GTP tunnel requires an identifier for the tunnel and IP

addresses for both directions these are already included in RANAP RAB

Assignment messages

5.4.2.3 IU PS USER PLANE PROTOCOL STACK Iu PS User Plane

multiple packet data flows are multiplexed on one or several AAL5 PVCs (Permanent Virtual Circuit)

GTP-U (User Plane part of GPRS Tunneling Protocol) is the multiplexing layer that provides identities for individual packet data flow

each flow uses UDP connectionless transport and IP addressing

5.4.3 RANAP PROTOCOL

RANAP defines interactions between RNS and CN the signaling protocol in Iu that contains all the

control information specified for Radio Network Layer

implemented by various RANAP Elementary Procedures (EP)

each RANAP function may require execution of one or more EPs

three classes of EPclass 1 EP

request and response (failure or success)class 2 EP

request without responseclass 3 EP

request and possibility for one or more responses

RANAP functions relocation RAB (Radio Access Bearer) management Iu release report unsuccessfully transmitted data common ID management paging

management of tracing UE–CN signaling transfer security mode control management of overload reset location reporting

RANAP FUNCTION--

Relocation： handles both SRNS relocation and hard handover (including inter-system case to/from GSM) SRNS relocation

the serving RNS functionality is relocated from one RNS to another without changing the radio resources and without interrupting the user data flow

prerequisite： all Radio Links are already in the same DRNC that is the target for the relocation

Inter-RNS hard handoverrelocate the serving RNS functionality from one RNS to another and to change the radio resources correspondingly by a hard handover in Uu interface

prerequisite： UE is at the border of the source and target cells

RANAP FUNCTION--

RAB (Radio Access Bearer) management：combines all RAB handling RAB set-up modification of the characteristics of an

existing RAB clearing an existing RAB

Iu release releases all resources (Signaling link and U-

Plane) from a given instance of Iu related to the specified UE

RANAP FUNCTION--

Reporting unsuccessfully transmitted data allows CN to update its charging records with

information from UTRAN if part of the data sent was not successfully sent to UE

Common ID management the permanent identification of the UE is sent

from CN to UTRAN to allow paging coordination from possibly two different CN domains

RANAP FUNCTION--

Paging used by CN to page an idle UE for a UE

terminating service request, such as a voice call a paging message is sent from CN to UTRAN with

the UE common identification (permanent Id) and the paging area

UTRAN will either use an existing signaling connection, if one exists, to send the page to UE or broadcast the paging in the requested area

RANAP FUNCTION--

Management of tracing CN may, for operation and maintenance

purposes, request UTRAN to start recording all activity related to a specific UE–UTRAN connection

RANAP FUNCTION--

UE–CN signaling transfer transfer of the first UE message from UE to

UTRAN example

a response to paging a request of a UE-originated call a registration to a new area

it also initiates the signaling connection for Iu direct transfer

used for carrying all consecutive signaling messages over the Iu signaling connection in both uplink and downlink directions

RANAP FUNCTION--

Security mode control used to set the ciphering or integrity checking on

or off when ciphering is on

the signaling and user data connections in the radio interface are encrypted with a secret key algorithm

when integrity checking is on an integrity checksum, further secured with a

secret key, is added to some or all of the Radio Interface signaling messages

this ensures that the communication partner has not changed, and the content of the information has not been altered

RANAP FUNCTION--

Management of overload control the load over Iu interface against

overload due example, to process overload at the CN or

UTRAN a simple mechanism is applied that allows stepwise reduction of the load and its stepwise resumption [( 中斷後的 ) 重新開始 ], triggered by a timer

RANAP FUNCTION--

Reset reset the CN or the UTRAN side of Iu interface in

error situations one end of the Iu may indicate to the other end

that it is recovering from a restart, and the other end can remove all previously established connections

RANAP FUNCTION--

Location reporting allows CN to receive information on the location

of a given UE includes two elementary procedures

control the location reporting in RNC send the actual report to CN

5.4.4 IU USER PLANE PROTOCOL Iu User Plane protocol

in the Radio Network Layer of Iu User Plane

defined to be independent of CN domain

purpose carry user data related to RABs

over Iu interface the protocol performs either a fully

transparent operation, or framing for user data segments

the protocol also performs some basic control signaling to be used for initialization and online control

the protocol has two modes transparent mode

本身並不會加入任何協定檔頭，亦即上層所傳送的通訊協定會直接加上 GTP-U檔頭後送出， Iu FP本身並不加入任何資料

applied for RABs that assume fully transparent operation

support mode所提供的傳輸協定，包含速率控制與時間限制，可用於支援 real-time的語音傳輸

for predefined SDU (Service Data Unit) sizesperforms framing of user data into

segments of predefined size

the SDU sizes typically correspond toAMR (Adaptive Multirate Codec) speech

frames, orthe frame sizes derived from the data rate

of a CS data call control procedures for initialization and rate

control are defined, and a functionality is specified for indicating the quality of the frame based, for example, on CRC from radio interface

5.4.5 PROTOCOL STRUCTURE OF IU BC, AND THE SABP PROTOCOL

Iu BC interface connects RNC in UTRAN with the broadcast

domain of Core Network, namely with Cell Broadcast Centre

used to define Cell Broadcast information that is transmitted to mobile user via Cell Broadcast Service

e.g. name of city/region visualized on the mobile phone display

Iu BC is a control plane only interface the protocol structure of Iu BC is shown as

follows

SABP (Service Area Broadcast Protocol) provides the capability for Cell

Broadcast Centre in CN to define, modify and remove cell broadcast messages from RNC

SABP has the following functions message handling

broadcast of new messagesamendment [ 修正 ] of existing

broadcast messagesprevention of broadcasting of

specific messages

load handling responsible for determining the loading of the

broadcast channels at any particular point in time reset

permits CBC to end broadcasting in one or more Service Areas

5.5 UTRAN INTERNAL INTERFACES

5.5.1 RNC–RNC Interface (Iur Interface) and the RNSAP Signaling

5.5.2 RNC–Node B Interface and the NBAP Signaling

5.5.1 RNC–RNC INTERFACE (IUR INTERFACE) AND THE RNSAP SIGNALLING

5.5.1.1 Iur1： Support of the Basic Inter-RNC Mobility

5.5.1.2 Iur2： Support of Dedicated Channel Traffic

5.5.1.3 Iur3： Support of Common Channel Traffic

5.5.1.4 Iur4： Support of Global Resource Management

The following figure shows the protocol stack of RNC to RNC interface (Iur interface)

Iur interface provides four distinct functions support of basic inter-RNC mobility (Iur1) support of dedicated channel traffic (Iur2) support of common channel traffic (Iur3) support of global resource management (Iur4)

5.5.1.1 IUR1： SUPPORT OF THE BASIC INTER-RNC MOBILITY

This functionality requires the basic module of RNSAP signaling provides the functionality needed for the

mobility of the user between two RNCs does not support the exchange of any user data

traffic

If this module is not implemented the only way for a user connected to UTRAN via

RNS1 to utilize a cell in RNS2 is to disconnect itself temporarily from UTRAN (release the RRC connection)

The functions offered by Iur basic module include support of SRNC relocation support of inter-RNC cell and UTRAN registration

area update support of inter-RNC packet paging reporting of protocol errors

Since this functionality does not involve user data traffic across Iur User Plane and Transport Network Control Plane

protocols are not needed

5.5.1.2 IUR2： SUPPORT OF DEDICATED CHANNEL TRAFFIC

This functionality requires dedicated channel module of RNSAP

signaling allows dedicated and shared channel traffic between

two RNCs

This functionality requires also User Plane Frame Protocol (FP) for dedicated and

shared channel Transport Network Control Plane protocol

(Q.2630.1 [Q.aal2 CS1]) used for the set-up of transport connections (AAL2 connections)

Frame Protocol for dedicated channels (DCH FP) defines the structure of the data frames carrying the

user data the control frames used to

exchange measurements and control information

Frame Protocol for common channels (CCH FP) describes the User plane procedure for the

shared channel

The functions offered by Iur DCH module establishment, modification and release of the

dedicated and shared channel in DRNC due to handovers in dedicated channel state

set-up and release of dedicated transport connections across Iur interface

transfer of DCH Transport Blocks between SRNC and DRNC

management of the radio links in DRNS via dedicated measurement report procedures power setting procedures compress mode control procedures

5.5.1.3 IUR3： SUPPORT OF COMMON CHANNEL TRAFFIC

This functionality allows the handling of common channel (i.e. RACH,

FACH and CPCH) data streams across Iur interface Note

CPCH： Common Packet CHannel RACH： Random Access CHannel FACH： Forward Access CHannel

It requires Common Transport Channel module of RNSAP

protocol Iur Common Transport Channel Frame Protocol

(CCH FP) If signaled AAL2 connections are used

Q.2630.1 [Q.aal2 CS1] signaling protocol of the Transport Network Control Plane is needed

The functions offered by Iur common transport channel module set-up and release of the transport connection

across Iur for common channel data streams splitting of the MAC layer between SRNC (MAC-d)

and DRNC (MAC-c) flow control between MAC-d and MAC-c

註：負責處理傳輸通道的MAC層可細分為MAC的三個子層 MAC-b

負責將要廣播 (broadcast)的邏輯通道 (logical channel)對應到相對的傳輸通道 (transport channel)

在 UE都有MAC-b層在 Node B上有負責每個 cell的MAC-b層

MAC-d負責管理專屬 (dedicated)通道在 UE都有一個MAC-d層在 SRNC上有負責每個 UE的MAC-d層

MAC-c/sh負責處理在一般 (common)與共享 (shared)通道中的資訊

在 UE上都有MAC-c/sh層在 CRNC (Controlling RNC)上有負責一個 cell的

MAC-c/sh層

5.5.1.4 IUR4： SUPPORT OF GLOBAL RESOURCE MANAGEMENT This provides signaling to support enhanced

radio resource management and O&M features across Iur interface

The function is considered optional This function has been introduced in

subsequent releases for the support of common radio resource management between

RNCs advanced positioning methods Iur optimization

The functions offered by Iur global resource module transfer of cell information and measurements

between two RNCs transfer of positioning parameters between

controller transfer of Node B timing information between

two RNCs

5.5.2 RNC–NODE B INTERFACE AND THE NBAP SIGNALING

5.5.2.1 Common NBAP and the Logical O&M5.5.2.2 Dedicated NBAP

Figure 5.10 shows the protocol stack of RNC–Node B interface (Iub interface)

Figure 5.11 shows the logical model of Node B seen from the controlling RNC

Figure 5.11 Logical Model of Node B

Logical model of Node B includes the logical resources provided by Node B to UTRAN

(via Controlling RNC) - depicted as "cells" which include the following physical channel resources DPCH (Dedicated Physical Channel)PDSCH (Physical Downlink Shared Channel)PUSCH (Physical Uplink Shared Channel)

the dedicated channels which have been established on Node B

the common transport channels that Node B provides to RNC

Elements of the logical model1. Node B Communication Contexts for dedicated

and shared channels corresponds to all the dedicated

resources that are necessary for a user in dedicated mode and using dedicated and/or shared channels as restricted to a given Node B

attributes (not exhaustive) list of Cells where dedicated and/or shared physical resources are used

list of DCH which are mapped on the dedicated physical resources for that Node B Communication Context

list of DSCH and USCH [TDD] which are used by the respective UE

the complete DCH characteristics for each DCH, identified by its DCH-identifier

the complete Transport Channel characteristics for each DSCH and USCH, identified by its Shared Channel identifier

list of Iub DCH Data Ports list of Iub DSCH Data ports and Iub USCH data ports

FDD – up to one Iub TFCI2 Data Port

for each Iub DCH Data Port, the corresponding DCH and cells which are carried on this data port

for each Iub DSCH and USCH data port, the corresponding DSCH or USCH and cells which serve that DSCH or USCH

physical layer parameters (outer loop power control, etc)

2. Common Transport Channel configured in Node B, on request of CRNC attributes (not exhaustive)

Type (RACH, CPCH [FDD], FACH, DSCH, USCH [TDD], PCH)

Associated Iub RACH Data Port for a RACH, Iub CPCH Data Port for a CPCH [FDD], Iub FACH Data Port for a FACH, Iub PCH Data Port for PCH

Physical parameters

3. Transport network logical resources

3.1 Node B Control Port Functionality

exchange the signaling information for the logical O&M of Node B

the creation of Node B Communication Contexts

the configuration of the common transport channels that Node B provides in a given cell

PCH and BCH control information between the RNC and the Node B

Node B Control Port corresponds to one signaling bearer between the controlling RNC and the Node B

There is one Node B Control Port per Node B

3.2 Communication Control Portused to send the procedures for controlling the connections between radio links and Iub DCH data ports from RNC to Node B for control of Node B Communication Contexts

one signaling bearer between RNC and Node B can at most correspond to one Communication Control Port

Node B may have multiple Communication Control Ports (one per Traffic Termination Point)

3.3 Traffic Termination Pointrepresents DCH, DSCH and USCH [TDD] data streams belonging to one or more Node B Communication Contexts (UE contexts), which are controlled via one Communication Control Port

3.4 Iub RACH Data Port3.5 Iub CPCH Data Port [FDD]3.6 Iub FACH Data Port3.7 Iub PCH Data Port3.8 Iub FDD TFCI2 Data Port3.9 Iub DSCH Data Port3.10 Iub TDD USCH Data Port3.11 Iub DCH Data Port

5.5.2.1 COMMON NBAP AND THE LOGICAL O&M Iub interface signaling (NBAP, Node B

Application Part) is divided into two essential components common NBAP

defines the signaling procedures across the common signaling link

dedicated NBAPused in the dedicated signaling link

User Plane Iub frame protocols define the structures of the frames the basic inband control

procedures for every type of transport channel (i.e. for every type of data port of the model)

Q.2630.1 [Q.aal2 CS1] signaling used for dynamic

management of AAL2 connections used in User Plane

Common NBAP (C-NBAP) procedures used for the signaling that is not related to one

specific UE context already existing in Node B defines all the procedures for the logical O&M

(Operation and Maintenance) of Node Bsuch as configuration and fault management

Main functions of Common NBAP set-up of the first radio link of one UE, and

selection of the traffic termination point cell configuration handling of the RACH/FACH/CPCH and PCH

channels initialization and reporting of Cell or Node B

specific measurement Location Measurement Unit (LMU) control fault management

5.5.2.2 DEDICATED NBAP

When the RNC requests the first radio link for one UE via C-NBAP Radio Link Set-up procedure Node B assigns a traffic termination point for the

handling of this UE context every subsequent signaling related to this mobile

is exchanged with dedicated NBAP (D-NBAP) procedures across the dedicated control port of the given Traffic Termination Point

Main functions of the Dedicated NBAP addition, release and reconfiguration of radio

links for one UE context handling of dedicated and shared channels handling of softer combining initialization and reporting of radio link specific

measurement radio link fault management

5.6 UTRAN ENHANCEMENTS AND EVOLUTION

5.6.1 IP Transport in UTRAN5.6.2 Iu Flex5.6.3 Stand Alone SMLC and Iupc Interface5.6.4 Interworking between GERAN and

UTRAN, and the Iur-g Interface

Release’99 UTRAN architecture defines the basic set of network elements and

interface protocols for the support of Release ’99 WCDMA radio interface

Enhancement of the Release’99 UTRAN architecture support new WCDMA radio interface features to

provide a more efficient, scalable and robust 3GPP system architecture

Four most significant additions to the UTRAN architecture introduced in Release 5 are described in the subsequent sections

5.6.1 IP TRANSPORT IN UTRAN ATM

the transport technology used in the first release of UTRAN

IP transport introduced in Release 5

In addition to the initially defined option of AAL2/ATM, user plane FP frames can also be conveyed over UDP/IP protocols on Iur/Iub over RTP/UDP/IP protocols in Iu CS interface

5.6.2 IU FLEX Release’99 architecture

presented in Figure 5.3 only one MSC and one SGSN

connected to RNC i.e. only one Iu PS and Iu CS

interface in the RNC Iu flex (flexible)

allows one RNC to have more than one Iu PS and Iu CS interface instances with the core

Main benefits of this feature possible load sharing

between core network nodes

5.6.3 STAND ALONE SMLC AND IUPC INTERFACE Location-based services

expected to be a very important source of revenue for mobile operators

a number of different applications are expected to be available and largely used

UTRAN architecture includes a stand alone Serving Mobile Location Centre (stand alone SMLC, or, simply, SAS)a new network element for handling of

positioning measurements and calculation of the mobile station position

SAS connected to RNC via Iupc interface Positioning Calculation Application Part (PCAP) is

the L3 protocol used for RNC-SAS signaling SAS performs the following procedures

provides positioning (GPS related) data to RNC

performs the position calculation function for UE assisted GPS

SAS and Iupc interface are optional elements Iupc

the first version, supported only Assisted GPS later versions, support for other positioning

methods

5.6.4 INTERWORKING BETWEEN GERAN AND UTRAN, AND THE IUR-G INTERFACE

Iu interface scheduled to be part of the GSM/EDGE Radio Access

Network (GERAN) in GERAN Release 5 allows reusing 3G Core Network also for GSM/EDGE

radio interface (and frequency band), but also allows a more optimized interworking between the two radio technologies

Effect RNSAP basic mobility module is enhanced to

allow the mobility to and from GERAN cells in the target and the source

RNSAP global module is enhanced in order to allow GERAN cells measurements to be exchanged between controllers

allows a Common Radio Resource Management (CRRM) between UTRAN and GERAN radios

Iur-g interface refer to the above-mentioned set of Iur

functionalities that are utilized also by GERAN

5.7 UMTS CORE NETWORK ARCHITECTURE AND EVOLUTION

5.7.1 Release’99 Core Network Elements5.7.2 Release 5 Core Network and IP

Multimedia Sub-system

UMTS radio interface, WCDMA a bigger step in radio access evolution from GSM

networks UMTS core network

did not experience major changes in 3GPP Release’99 specification

Release’99 structure was inherited from GSM core network both UTRAN and GERAN based radio access

network connect to the same core network

5.7.1 RELEASE ’99 CORE NETWORK ELEMENTS Two domains of Release’99 core network

Circuit Switched (CS) domain Packet Switched (PS) domain

The division comes from the different requirements for data depending on whether it is real time (circuit

switched) or non-real time (packet data)

Figure 5.12 Release’99 core network

structure with both CS and PS domains

Registers HLR, VLR, EIR

Service Control Point (SCP) the link for providing a

particular service to end user

CS domain has the following elements Mobile Switching Centre (MSC), including Visitor

Location Register (VLR) Gateway MSC (GMSC)

PS domain has the following elements Serving GPRS Support

Node (SGSN) covers similar

functions as MSC for packet data, including VLR type functionality

Gateway GPRS Support Node (GGSN) connects PS core

network to other networks, e.g. to the Internet

In addition to the two domains, the network needs various registers for proper operation Home Location Register (HLR) Equipment Identity Register (EIR)

contains the information related to the terminal equipment

can be used to, e.g., prevent a specific terminal from accessing the network

5.7.2 RELEASE 5 CORE NETWORK AND IP MULTIMEDIA SUB-SYSTEM Release 4 included the change in core

network CS domain MSC was divided into MSC server and Media

Gateway (MGW) GMSC was divided into GMSC server and MGW

Release 5 contains the first phase of IP Multimedia Sub-

system (IMS) this will enable a standardized approach for IP-

based service provision via PS domain

Release 6 enhance IMS to allow the

provision of services similar to CS domain services from PS domain

Release 5 architecture is presented in Figure 5.13 Home Subscriber Server (HSS)

shown as an independent item Session Initiation Protocol (SIP)

the key protocol between terminal and IMS

the basis for IMS-related signaling

MSC or GMSC server takes care of the control functionality

as MSC or GMSC, respectively user data goes via Media Gateway (MGW) one MSC/GMCS server can control

multiple MGWs this allows better scalability of the

network when data rates increase with new data services

in this case, only the number of MGWs needs to be increased

MGW performs actual switching for user data and network interworking processing e.g., echo cancellation or speech

decoding/ encoding

IMS includes the following key elements Media Resource Function (MRF)

controls media stream resources or mixes different media streams

Call Session Control Function (CSCF) the first contact point to

terminal in the IMS (as a proxy)

handling of session states acting as a firewall towards

other operator’s networks

Media Gateway Control Function (MGCF) handle protocol conversions control a service coming via CS

domain and perform processing in an MGW, e.g. for echo cancellation