WCDMA Radio Principles

UA06 R99 Radio Principles - Page 1All Rights Reserved © Alcatel-Lucent @@YEAR

All Rights Reserved © Alcatel-Lucent @@YEAR

9300 W-CDMAUA06 R99 Radio Principles

STUDENT GUIDE

TMO18042 D0 SG DENI1.0Issue 1

All rights reserved © Alcatel-Lucent @@YEAR Passing on and copying of this document, use and communication of its

contents not permitted without written authorization from Alcatel-Lucent



UA06 R99 Radio Principles9300 W-CDMA

2

Empty page

Switch to notes view!

This page is left blank intentionally




3

Terms of Use and Legal Notices

Switch to notes view!1. Safety Warning

Both lethal and dangerous voltages may be present within the products used herein. The user is strongly advised not to

wear conductive jewelry while working on the products. Always observe all safety precautions and do not work on the

equipment alone.

The equipment used during this course may be electrostatic sensitive. Please observe correct anti-static precautions.

2. Trade Marks

Alcatel-Lucent and MainStreet are trademarks of Alcatel-Lucent.

All other trademarks, service marks and logos (“Marks”) are the property of their respective holders, including Alcatel-

Lucent. Users are not permitted to use these Marks without the prior consent of Alcatel-Lucent or such third party owning

the Mark. The absence of a Mark identifier is not a representation that a particular product or service name is not a Mark.

Alcatel-Lucent assumes no responsibility for the accuracy of the information presented herein, which may be subject to

change without notice.

3. Copyright

This document contains information that is proprietary to Alcatel-Lucent and may be used for training purposes only. No

other use or transmission of all or any part of this document is permitted without Alcatel-Lucent’s written permission, and

must include all copyright and other proprietary notices. No other use or transmission of all or any part of its contents may

be used, copied, disclosed or conveyed to any party in any manner whatsoever without prior written permission from

Alcatel-Lucent.

Use or transmission of all or any part of this document in violation of any applicable legislation is hereby expressly

prohibited.

User obtains no rights in the information or in any product, process, technology or trademark which it includes or

describes, and is expressly prohibited from modifying the information or creating derivative works without the express

written consent of Alcatel-Lucent.

All rights reserved © Alcatel-Lucent @@YEAR

4. Disclaimer

In no event will Alcatel-Lucent be liable for any direct, indirect, special, incidental or consequential damages, including

lost profits, lost business or lost data, resulting from the use of or reliance upon the information, whether or not Alcatel-

Lucent has been advised of the possibility of such damages.

Mention of non-Alcatel-Lucent products or services is for information purposes only and constitutes neither an

endorsement, nor a recommendation.

This course is intended to train the student about the overall look, feel, and use of Alcatel-Lucent products. The

information contained herein is representational only. In the interest of file size, simplicity, and compatibility and, in some

cases, due to contractual limitations, certain compromises have been made and therefore some features are not entirely

accurate.

Please refer to technical practices supplied by Alcatel-Lucent for current information concerning Alcatel-Lucent equipment

and its operation, or contact your nearest Alcatel-Lucent representative for more information.

The Alcatel-Lucent products described or used herein are presented for demonstration and training purposes only. Alcatel-

Lucent disclaims any warranties in connection with the products as used and described in the courses or the related

documentation, whether express, implied, or statutory. Alcatel-Lucent specifically disclaims all implied warranties,

including warranties of merchantability, non-infringement and fitness for a particular purpose, or arising from a course of

dealing, usage or trade practice.

Alcatel-Lucent is not responsible for any failures caused by: server errors, misdirected or redirected transmissions, failed

internet connections, interruptions, any computer virus or any other technical defect, whether human or technical in

nature

5. Governing Law

The products, documentation and information contained herein, as well as these Terms of Use and Legal Notices are

governed by the laws of France, excluding its conflict of law rules. If any provision of these Terms of Use and Legal

Notices, or the application thereof to any person or circumstances, is held invalid for any reason, unenforceable including,

but not limited to, the warranty disclaimers and liability limitations, then such provision shall be deemed superseded by a

valid, enforceable provision that matches, as closely as possible, the original provision, and the other provisions of these

Terms of Use and Legal Notices shall remain in full force and effect.




4

Blank Page






5

Course Outline

About This CourseCourse outline

Technical support

Course objectives

1. Topic/Section is Positioned HereXxx

Xxx

Xxx

2. Topic/Section is Positioned Here






1. UTRAN System Description

1. UTRAN System Description

2. WCDMA for UMTS

1. WCDMA for UMTS

3. UTRAN_scenario

1. UTRAN_scenario

4. Glossary

1. Glossary




6

Course Outline [cont.]






7

Course Objectives


Welcome to UA06 R99 Radio Principles

Upon completion of this course, you should be able to:

� describe WCDMA principles for UMTS

� describe mobile system standards evolution

� describe UMTS services , new capacity figures and service architecture

� draw the UTRAN architecture with the protocol stack

� define a Radio Resource in 3G and describe WCDMA principles for UMTS

� describe how the user can access to the network and asks for a 3G service

� describe UTRAN functions and state protocols.




8

Course Objectives [cont.]






9

About this Student Guide

� Switch to notes view!Conventions used in this guide

Where you can get further information

If you want further information you can refer to the following:

� Technical Practices for the specific product

� Technical support page on the Alcatel website: http://www.alcatel-lucent.com

Note

Provides you with additional information about the topic being discussed.

Although this information is not required knowledge, you might find it useful

or interesting.

Technical Reference (1) 24.348.98 – Points you to the exact section of Alcatel-Lucent Technical

Practices where you can find more information on the topic being discussed.

WarningAlerts you to instances where non-compliance could result in equipment

damage or personal injury.




10

About this Student Guide [cont.]

� Switch to notes view!





11

Self-assessment of Objectives

� At the end of each section you will be asked to fill this questionnaire

� Please, return this sheet to the trainer at the end of the training


Instructional objectives Yes (or globally yes)

No (or globally no)

Comments

1 To be able to XXX

2

Contract number :

Course title :

Client (Company, Center) :

Language : Dates from : to :

Number of trainees : Location :

Surname, First name :

Did you meet the following objectives ?

Tick the corresponding box

Please, return this sheet to the trainer at the end of the training

��




12

Self-assessment of Objectives [cont.]


Instructional objectives Yes (or Globally yes)

No (or globally no)

Comments

Thank you for your answers to this questionnaire

Other comments

��

Section 1 � Pager 1


3JK10655AAAAWBZZA Edition 1

Do not delete this graphic elements in here:

1All Rights Reserved © Alcatel-Lucent @@YEAR

UTRAN System Description9300 W-CDMA

UA06 R99 Radio PrinciplesTMO18042 D0 SG DENI1.0

Edition 1

Section 1UTRAN System Description





9300 W-CDMA � UA06 R99 Radio PrinciplesUTRAN System Description

1 � 2

Blank Page


Conversion into Alcatel-Lucent templateScholle, Martin2007-06-2103

RemarksAuthorDateEdition

Document History






1 � 3

Objectives

� To be able to draw the UTRAN architecture with the protocol stack (radio and Iu) of each network element and to define the channels generated by these protocols.






1 � 4

Objectives [cont.]







1 � 5

Table of Contents

� Logical Architecture� UTRAN Situation & Core Network in 3GPP R4

� UTRAN Logical Architecture� Interfaces� Network Element Function

� Network Protocols� Protocols in UTRAN� Protocol Stack on the Interfaces� General model� Iub protocols� Iur Protocols

� Radio Channels� Global Situation� RAB Presentation� Radio Channels, Protocols & Network Elements

� Radio Bearers� Logical Channels� Why Transport Channels?� Structure of a Transport Channel� Transport Channels: Example� Transport Channels

� Common Transport Channels� Dedicated Transport Channels� Mapping Logical / Transport Channels� Physical Channels� Physical Channel List� Downlink� Uplink� Physical Channels: Structure

� UTRAN Radio Protocols� Radio protocol stack� Radio Resource Control (RRC)� PDCP and BMC Protocols� Radio Link Control (RLC)� Medium Access Control (MAC)� The Physical Layer

� Exercises� MAC protocol

Page

1 Logical Architecture 71.1 UTRAN Situation & Core Network in 3GPP R4 81.2 UTRAN Logical Architecture 91.3 Interfaces 101.4 Network Element Function 11

2 Network Protocols 132.1 Protocols in UTRAN 142.2 Protocol Stack on the Interfaces 152.3 General model 162.4 Iub protocols 172.5 Iur Protocols 18

3 Radio Channels 203.1 Global Situation 213.2 RAB Presentation 223.3 Radio Channels, Protocols & Network Elements 233.4 Radio Bearers 243.5 Logical Channels 253.6 Why Transport Channels? 273.7 Structure of a Transport Channel 283.8 Transport Channels: Example 303.9 Transport Channels 313.10 Common Transport Channels 323.11 Dedicated Transport Channels 353.12 Mapping Logical / Transport Channels 363.13 Physical Channels 383.14 Physical Channel List 393.15 Downlink 403.16 Uplink 413.17 Physical Channels: Structure 42

4 UTRAN Radio Protocols 434.1 Radio protocol stack 444.2 Radio Resource Control (RRC) 454.3 PDCP and BMC Protocols 464.4 Radio Link Control (RLC) 474.5 Medium Access Control (MAC) 484.6 The Physical Layer 49

5 Exercises 505.1 MAC protocol 51






1 � 6

Table of Contents [cont.]








1 � 7

1 Logical Architecture






1 � 8


1.1 UTRAN Situation & Core Network in 3GPP R4

Core Network

PS-CN

Access Network

Iu-PS

External Networks

HLR

PSTN

IN network

UTRAN

RNCRNC

Node B

PDN

CS Links

PS Links

Gb

Backbone

iGGSiGGSNN

SGSNGSM

BSS

BSC

BTSPCU

CS-CN

MSC Server

MGW GMSC

Iu-CS

A Public Land Mobile Network (PLMN) is composed of 2 main parts:

The Access Network (AN) provides the radio interface and radio resource management for mobile

communications toward the Core Network (CN).

The Core network is in charge of User Equipment (UE) Mobility (MM) and Session (SM) management. It

also deals with the external networks for voice call establishment or data session establishment.

The UMTS Terrestrial Radio Access Network (UTRAN) is the UMTS Access Network; it’s composed of

Node Bs and Radio Network Controllers (RNCs).

An ATM switch interfaces the UTRAN and the CN:

• Iu-CS interface for the Circuit Switched Core Network (CSCN).

• Iu-PS interface for the Packet Switched Core Network (PSCN).

The PLMN connects specifically to the Public Switched Telephone Network (PSTN) for voice or to the

Packet Data Network (PDN) for data.

The CN includes the Intelligent Network (IN) for value-added services.

Example of services:

For voice:

• Voice Call Prepaid Service

• SMS service

• Call Waiting






1 � 9


1.2 UTRAN Logical Architecture

Core Network

UTRAN

UE

Iub Iub

Iu-CS Iu-PS

Iur

Uu Interface

RNS

CS-CN PS-CN

RNC RNC

Node B Node B

UEs

CN

� 2 separated domains: Circuit Switched (CS) and Packet Switched (PS) which reuse the

infrastructure of GSM and GPRS respectively.

UTRAN

� new radio interface: CDMA

� new transmission technology: ATM

CN independent of AN

� The specificity of the access network due to mobile system should be transparent to the core

network, which may potentially use any access technique.

� Radio specificity of the access network is hidden to the core network.

� UE radio mobility is fully controlled by UTRAN.

Some correspondences with GSM:

� CN NSS Uu Um

� UTRAN BSS Iub A-bis

� RNC BSC Iur no equivalent

� Node-B BTS Iu-CS A

� UE MS Iu-PS Gb






1 � 10


1.3 Interfaces

Open Interfaces:

• The function of the Network Elements have been clearly specified by the 3GPP.• Their internal implementation issues are open for the manufacturer• All the interfaces have been defined in such a detailed level that the equipment at the endpoints can be from different manufacturers.

• “Open Interfaces” aim at motivating competition between manufacturers.

Physical implementation of Iu interfaces

•Each Iu Interface may be implemented on any physical connection using any transport technology, mainly on E1 (cable), STM1 (Optic fiber) and micro-waves.•ATM will be provided in the 3GPP R4 release and IP is for the 3GPP R6

A manufacturer can produce only the Node-B (and not the RNC). This is not possible in GSM (A-bis is a

proprietary interface)

The Iur physical connection can go through the CN using common physical links with Iu-CS and Iu-PS.

However there is a direct logical connection between the 2 RNCs: the Iur information is not handled by

the CN.






1 � 11


1.4 Network Element Function

RNC: Radio Network Controller

It is the intelligent part of the UTRAN:

- Radio resource management (code allocation, Power Control, congestion control, admission control)- Call management for the users- Connection to CS and PS Core Network- Radio mobility management

Iub IubIur

RNS

Node B Node B

RNC RNC

An RNS (Radio Network Subsystem) contains one RNC (Radio Network Controller) and at least one Node-B.

The RNC takes a more important place in UTRAN than the BSC in the GSM BSS. Indeed RNC can perform

soft HO, while in GSM there is no connection between BSCs and only hard HO can be applied.






1 � 12


1.4 Network Element Function [cont.]

Node-B

A Node-B can be considered, as first approximation, like a transcoderbetween the data received by antennas and the data in the ATM cell on the Iub.

- Radio transmission and reception handling- Involved in the mobility management- Involved in the power control

Iub

RNC

Node B

ATM Transport Technology

An RNS (Radio Network Subsystem) contains one RNC (Radio Network Controller) and at least one Node-B.

A Node-B is also more complex than the GSM BTS, because it handles softer HO.

Controlling RNC (CRNC): a role an RNC can take with respect to a specific set of Node-Bs (ie those Node-

Bs belonging to the same RNS). There is only one CRNC for any Node-B. The CRNC has the overall control

of the logical resources of its Node-Bs






1 � 13

2 Network Protocols






1 � 14

2 Network Protocols

2.1 Protocols in UTRAN

Uu Interface

Core Network

RNC RNC

Node B

Iub

Iu

Iur

Iu Protocols

� The Iu protocols� Used to exchange data (traffic

and signaling) between RNCs, Node Bs and the Core Network.

Radio Protocols

� The Radio protocols� Used to process the data sent on

the air and for the signaling between UTRAN and the UEs

� NAS Signaling� Signaling between a UE and

the Core Network.

� Typically, the Authentificationand the Location

NAS Signaling

Iu Protocols :

� RANAP: Radio Access Network Application Protocol,

� RNSAP: Radio Network Sub-system Application Protocol,

� NBAP: Node B Application Protocol,

� ALCAP is a generic name for the signalling protocols of the Transport Network Control

� Plane used to establish/release Data Bearers.

� It makes establishment/release of Data Bearers on request of the Application Protocol.

Radio Protocols :

� RRC: Radio Resource Control

� RLC: Radio Link Control

� MAC: Medium Access Control

� NAS refers to higher layers (3 to 7). Entities of this part will exchange tele-services and bearer

services






1 � 15

2 Network Protocols

2.2 Protocol Stack on the Interfaces based on ATM

Iub

Iub

Iur

Iu- PS

Iu- CS

Node B

RNC

RNC

RNSAP

RANAP

RANAP

Iu UP

Voice

Iur FP

Iu UP

Data

Control plane User plane

Iub

Node B

CS-CN

PS-CN

RadioSig Voice

NBAPIub FP

RadioSig Voice Data

AAL5 AAL2

ATM

AAL5 AAL2

ATM

AAL5 AAL2

ATM

AAL5 AAL5

ATM

Data

Node B

AAL5 has been designed to adapt non real time, connectionless oriented data at variable bit rate (eg,

web browsing) to ATM.

AAL2 has been designed to adapt real time, connection oriented data at variable bit rate (eg, voice in

AMR) to ATM.






1 � 16

The same general protocol model is applied for all Iu interfaces:

Application Protocols:

Radio

Network

Layer

Transport

Network

Layer

Physical Layer

SignalingBearer(s)

SignalingBearer(s)

DataBearer(s)

ALCAP

ApplicationProtocol

DataStream(s)

Transport Network Control Plane

Transport Network User Plane


Control Plane

User Plane

- NBAP for Iub interface- RNSAP for Iur interface- RANAP for Iu-CS and Iu-PS interfaces

1. What is the purpose of the separation between the Radio Network Layer and the Transport Network Layer?

2. Why is ALCAP protocol necessary?


2.2.1 General model

The Iu protocols are responsible for exchanges of signalling and user data between two endpoints of an Iu interface (e.g. Node-B and RNC over the Iub interface) .

The ALCAP protocol is used to establish the AAL2 connections for the the data stream (user data & user signaling) of the Radio Network Layer.






1 � 17

ATM

Radio

Network

Layer

Transport

Network

Layer

Physical Layer

AAL5 AAL2

ALCAP

NBAPFrame Protocols(IubFP)

Control Plane User Plane

AAL5

RRC Connection Establishment*

Radio Link Establishment RABs*

NAS signalling*





2.2.2 Iub protocols

Note: AAL2 and AAL5 are sub-layers of ATM which provide some adaptation between the application

(voice, data, signalling) and the ATM layer.

NBAP

� is used to carry signalling (e.g Radio Link Establishment)

� Examples of actions of NBAP during Radio Link Establishment:

� signalling exchanges over Iub, which permits the RNC to reserve radio resources of Node-B

for the Radio Link

� signalling transaction with ALCAP, which will setup a Iub data bearer (on AAL2) to carry the

Radio Link

Frame Protocols

� At this stage Data Streams (carrying RABs, NAS signalling, SMS Cell Broadcast service, RRC

connection establishment…) have been mapped on transport channels

� The Frame Protocols (FP) define the structures of the frame and the basic in-band control

procedures for every type of transport channels.

ALCAP

� is used to set up AAL2 connections for Data Streams.

Bearers

� Data Streams are carried on AAL2, which enables better bandwidth efficiency for user packets but

requires its own signalling (ALCAP signalling is used to set up AAL2 connections for Data Streams).

� NBAP and ALCAP messages are carried on AAL5.






1 � 18

ATM

Radio

Network

Layer

Transport

Network

Layer

Physical Layer

...

AAL5 AAL2

ALCAP

RNSAPFrame

Protocols (Iur FP)

Control Plane User Plane

AAL5

RRC Connection Establishment*

Establishment of an additional radio link

to an UE (for soft HO)

RABs*NAS signalling*





2.2.3 Iur Protocols

Note: AAL2 and AAL5 are sub-layers of ATM which provide some adaptation between the application

(voice, data, signalling) and the ATM layer.

RNSAP

� It is used to carry signalling (e.g Radio Link Establishment)

� e.g. actions of RNSAP during Radio Link Establishment:

� signalling exchanges over Iur: the SRNC request the DRNC to reserve radio resources for the

Radio Link (the DRNC will afterwards reserve these radio resources in the suitable Node-B)

� signalling transaction with ALCAP, which will setup a Iur data bearer to carry the Radio Link

Frame Protocols

� At this stage Data Streams (carrying RABs, NAS signalling, SMS Cell Broadcast service, RRC

connection establishment…) have been mapped on transport channels

� The Frame Protocols (FP) define the structures of the frame and the basic in-band control

procedures for every type of transport channels.

ALCAP

� It is used to set up AAL2 connections for Data Streams.

Bearers

� Data Streams are carried on AAL2, which enables better bandwidth efficiency for user packets but

requires its own signalling (ALCAP signalling is used to set up AAL2 connections for Data Streams).

RNSAP and ALCAP messages are carried on AAL5.






1 � 19

2 Network Protocols

2.3 Protocol Stack on the Interfaces based on IP

Characteristics

� Optimized HSPA Offload

� Hybrid Iub

RNC

Node B

R99 over ATM

E1 Leased Lines

Ethernet

HSPA over IP

Low Cost Backhaul

GigE

STM

E1/T1 and Eth

SGSN

MSC Server

CS over ATM

PS over Eth

IP Evolution in UA06

As you can see, HYBRID IUB introduces a hybrid transport (ATM & IP) on the Iub interface on the RNC &

Node B. This functionality enables the operator to split delay sensitive traffic from non delay sensitive

traffic. R99 traffic is carried over E1 to secure voice transportation as well as all delay sensitive traffic,

whereas non-delay sensitive traffic is carried over IP, over a private IP network.

In the hybrid Iub interface, the R99, signaling and OAM traffic remains on the ATM/PCM and the HSPA

(HSDPA and E-DCH) is supported on IP/Ethernet. Hybrid Iub requires a 100Base-T Ethernet port in the Node

B and a Gigabit Ethernet board on the RNC side.






1 � 20


UTRAN Interfaces Based on IP (User Plane)

Voice

AAL2

ATM

Physical

Data

UDP / IP

ETH

Physical

GTP-uVoice

AAL2

ATM

Physical

Data

UDP / IP

ETH

Physical


The evolution of the Tranport network towards IP is applicable on 2 interfaces in UA06. The first possible IP

evolution is the introduction of the Hybrid Iub Interface, combining both traffic such as voice over ATM and

traffic such as data on IP over Ethernet. The second possible IP evolution consists in the Iu-PS interface

towards the SGSN This interface will carry the Internet packet on a IP backbone over Ethernet instead of

AAL5 over ATM






1 � 21


UTRAN Interfaces Based on IP (Control Plane)

RANAP

IP

ETH

Physical

M3UA

SCTP

SCCP

NBAP

AAL5

ATM

Physical

ALCAP

AAL5


The Iu-PS interface is an open interface between the RNC and the SGSN for the packet domain.

ATM and IP stacks for Iu-PS are supported.

On this interface, the SCCP supports transport of RANAP messages used by the Control Plane.

The ATM stack is like the Iu-CS interface.

The AAL5/ATM stack is used to transport IP packets across the Iu interface towards the packet-switched

domain.

The IP stack uses the MTP-3 User Adaptation Layer (or M3UA) and the Stream Control Transmission Protocol

(SCTP) to transport signaling over the IP network.

UDP/IP is used for the User Plane.

Dynamic management of GTP tunnel is ensured by the user plane towards the PS domain.

The physical layer is supported by OC-3/STM-1 and IP over Gigabit Ethernet.

The Transport Network Control plane is not necessary on the Iu-PS interface.






1 � 22

QUIZ!

A. Put the correct words in the spaces on the figure below

... ... ...

...

...

... ... ... ...

......

...

... ...

CS networks (PSTN, ISDN)

PS networks (internet)

...






1 � 23

3 Radio Channels






1 � 24

UTRAN SGSN GGSN PDN

“Internet”

UMTS Bearer Service External BearerService

UMTS Bearer Service

Radio Access Bearer Service

(RAB)CN BearerService

BackboneBearer Service

Iu BearerService

Radio BearerService

Uu Iu

Teleservice

UE

LogicalChannel

Transport Channel

PhysicalChannel

3 Radio Channels

3.1 Global Situation

A Radio Bearer is the service provided by a protocol entity (i.e. RLC protocol) for transfer of data between UE and UTRAN.

Radio bearers are the highest level of bearer services exchanged between UTRAN and UE.

Radio bearers are mapped successively on logical channels, transport channels and physical channels

(Radio Physical Bearer Service on the figure)






1 � 25

“The RAB provides confidential transport of signaling and user data between UE and CN with the appropriate QoS”.

UTRAN

UE UMTS Bearer

UMTS Bearers

RABs (mapped on Radio & Iu Bearers)

CN-CS

CN-PS

Radio Bearers Iu Bearers

RAB

RAB

RABRAB

UMTS Bearer

UMTS bearer services

3 Radio Channels

3.2 RAB Presentation

AMR 12.2/12.2, 64/64Conversational

(CS)

R2: 64/128, 64/384 64/144, 128/384, 144/384, 32/32, 64/64, 128/128, 144/144Background

(PS)

14.4/14.4Streaming (CS)

Example of available RAB in R4

R2: 64/128, 64/384 64/144, 128/384, 144/384, 32/32, 64/64, 128/128, 144/144Interactive (PS)






1 � 26

RRC

RLC

MAC

BMCPDCP

Physical Layer Physical Layer

NAS Signaling

RRC Sig.

Voice Web Browsing

SMS Cell Broadcast

Radio Bearers

Traffic Logical Ch.

…Transport Channels

Uu Interface

RNC Node B UE

Physical Channels

MAC

…

Transport Channels

3 Radio Channels

3.3 Radio Channels, Protocols & Network Elements

Control Logical Ch.

The radio protocols are responsible for exchanges of signalling and user data between the UE and the

UTRAN over the Uu interface:

User plane protocols

� These are the protocols implementing the actual Radio Access Bearer (RAB) service,

� i.e. carrying user data through the access stratum (EXAMPLES 1,2 and 4).

Control plane protocols

� These are the protocols for controlling the radio access bearers and the connection

� between the UE and the network from different aspects including requesting the service

� EXAMPLE 5), controlling different transmission resources, handover & streamlining etc...

� Also a mechanism for transparent transfer of Non Access Stratum (NAS) messages is included).

Some principles:

� The Radio Protocols are independent of the applied transport layer technology

� (ATM in R99): that may be changed in the future while the Radio Protocols remain intact.

� The main part of radio protocols are located in the RNC (and in the UE).

� The Node-B is mainly a relay between UE and RNC.






1 � 27

Signaling Radio Bearers (SRB)

SRBs can carry:- layer 3 signaling (e.g. RRC connection establishment)- NAS signaling (e.g location update)

There can be up to 4 SRBs per RRC connection (one UE has one RRC connection when connected to the UTRAN).

User Plane Radio Bearers

RABs are mapped on user plane RBs.

One RAB can be divided on RAB sub-flows and each sub-flow is mapped on one user plane RB.

e.g the AMR codec encodes/decodes speech into/from three sub-flows; each sub-flow can have its own channel coding.

3 Radio Channels

3.4 Radio Bearers

Please note that RAB (Radio Access Bearer) are only provided in the user plane.

What is a RRC connection?

� When the UE needs to exchange any information with the network, it must first establish a

signalling link with the UTRAN: it is made through a procedure with the RRC protocol and it is

called “RRC connection establishment”.

� During this procedure the UE will send an initial access request on CCCH to establish a signalling

link which will be carried on a DCCH.

� A given UE can have either zero or one RRC connection.






1 � 28

Control Channels (CCH)

Broadcast Control Channel (BCCH)

Traffic Channels (TCH)

Paging Control Channel (PCCH)

Dedicated Control Channel (DCCH)

Common Control Channel (CCCH)

Dedicated Traffic Channel (DTCH)

Common Traffic Channel (CTCH)

UTRAN UELogical Channels

3 Radio Channels

3.5 Logical Channels

The logical channels are divided into:

� Control channels for the transfer of control plane information

� Traffic channels for the transfer of user plane information






1 � 29

UL ( )/

DL ( )What type of information?

BCCH System control informatione.g cell identity, uplink interference level

PCCH Paging informatione.g CN originated call when the network does not know thelocation cell of the UE

CCCH Control informatione.g initial access (RRC connection request), cell update

DCCH Control information (but the UE must have a RRC connection)e.g radio bearer setup, measurement reports, HO

DTCH Traffic information dedicated to one UEe.g speech, fax, web browsing

CTCH Traffic information to all or a group of UEse.g SMS-Cell Broadcast

3 Radio Channels

3.5 Logical Channels [cont.]






1 � 30

3 Radio Channels

3.6 Why Transport Channels?

A transport channel offers a flexible pattern to arrange information on any service-specific rate, delay or coding before mapping it on a physical channel:

• it provides flexibility in traffic variation

• it enables multiplexing of transport channels on the same physical channel

Transport channels provide an efficient and fast flexibility in radio resource management.

Time

Traffic

Time Interval

Transport Channel

The transport channels provides a flexible pattern to exchange data between UTRAN and the UE at a

variable bit rate for the multimedia services.

The logical channels are mapped on the transport channels by the MAC protocols.

By this way the data are processed according to the QoS required before sending them to the Node B by

the Iub.






1 � 31

3 Radio Channels

3.7 Structure of a Transport Channel

168

168

168

168

168

168

168 bits

20 ms

Time Transmission Interval (TTI): periodicity at which a Transport Block Set is transferred by the physical layer on the radio interface

20 ms

Transport Block: basic unit exchanged over transport channels.

Transport Format (TF): it may be changed every TTI. Each TF must belong to the Transport Format Set (TFS) of the transport channel

168

168

>> The system delivers one Transport Block Set to the >> The system delivers one Transport Block Set to the

physical layer every TTIphysical layer every TTI: what is the delivery bit rate of the : what is the delivery bit rate of the

transport blocks to the physical layer during the first TTI?transport blocks to the physical layer during the first TTI?

20 ms 20 ms

A transport channel is defined by a Transport Format (TF) which may change every Time Transmission Interval (TTI).

The TF is made of a Transport Block Set. The Transport Block size and the number of Transport Block

inside the set are dynamical parameters.

The TTI is a static parameter and is set typically at 10, 20 or 40 ms.

For example,

For a video-call (CS service at 64 kbps)

� TTI = 20 ms

� TFS = (640* 0,2)

� Turbo coding (coding rate=1/3)

� 16 CRC bits

For a PS 64 kbps service

� TTI=20 ms

� TFS = (336* 0,1,2,3,4)

� Turbo coding (coding rate=1/3)

� 16 CRC bits






1 � 32

3 Radio Channels

3.7 Structure of a Transport Channel [cont.]

Transport Format (TF)

• Semi-static part (can be changed, but long process) Transmission Time Interval (TTI),Coding scheme...

• Dynamic part (may be changed easily) Size of transport block, Number of transport blocks per TTI

Transport Format Set (TFS)

It is the set of allowed Transport Formats for a transport channel, which is assigned by RRC protocol entity to MAC protocol entity.

MAC chooses TF among TFS.

MAC may choose another TF every TTI without interchanging with RRC protocol (fast radio resource control).

What is TTI (Transmission Time Interval)?

� it is equal to the periodicity at which a Transport Block Set is transferred by the physical layer on

the radio interface

� it is always a multiple of the minimum interleaving period (e.g. 10ms, the length of one Radio

Frame)

� MAC delivers one Transport Block Set to the physical layer every TTI.

What does the TFS provide ?

� The selection at each TTI of a number of transport block among the allowed list provides the

required flexibility for the variable traffic and allows to manages the priority.






1 � 33

3 Radio Channels

3.8 Transport Channels: Example

576

576

576

576

576

576

576 bits

576

576

40 ms

3. How many Transport 3. How many Transport Format(sFormat(s) may be chosen for this transport channel?) may be chosen for this transport channel?

4. Can you imagine why the transfer has been interrupted during 4. Can you imagine why the transfer has been interrupted during the third TTI? the third TTI?

Static PartTTI ?Coding scheme Turbo coding, coding rate=1/3

CRC 16 bits

Dynamic PartTransport Block Size ?

Transport Block Size Set 576*B (B=0,1,2,3,4)

1. Complete the table1. Complete the table

2.2. What is the delivery What is the delivery

bit rate of the transport bit rate of the transport blocks to the physical blocks to the physical

layer during the first TTI?layer during the first TTI?






1 � 34

3 Radio Channels

3.9 Transport Channels

Common Channels

Broadcast Channel (BCH)

Dedicated Channels

Paging Channel (PCH)

Random Access Channel (RACH)

Forward Access Channel (FACH)

Dedicated Channel (DCH)

Common Packet Channel (CPCH)

Downlink Shared Channel (DSCH)

UTRAN Transport Channels UE

The transport channels are divided into:

Common channels: they are divided between all or a group of UEs in a cell. They require in-band

identification of the UEs when addressing particular UEs.

Dedicated channels: it is reserved for a single UE only. In-band identification is not necessary, a given UE

is identified by the physical channel (code and frequency in FDD mode)






1 � 35

3 Radio Channels

3.10 Common Transport Channels

BCH: Broadcast Channel

A downlink transport channel that is used to carry BCCH. The BCH is always transmitted with high power over the entire cell with a low fixed bit rate.

>> The BCH is the only transport channel with a single transport>> The BCH is the only transport channel with a single transport format (no format (no

flexibility). Can you explain why?flexibility). Can you explain why?

PCH: Paging Channel

A downlink transport channel that is used to carry PCCH. It is always transmitted over the entire cell.

>> Is it possible to carry all types of information on the PCH?>> Is it possible to carry all types of information on the PCH?

BCH

� high power to reach all the user and low fixed bit rate so that all terminals can decode the data

rate whatever its ability: only one Transport Format because there is no need for flexibility (fixed

bit rate)

PCH

� only two transport channels can NOT carry user information: BCH and PCH.






1 � 36

3 Radio Channels

3.10 Common Transport Channels [cont.]

FACH: Forward Access Channel

A downlink transport channel that is used to carry control information. It may also carry short users packets. The FACH is transmitted over the entire cell or over only a part of the cell using beam-forming antennas. The FACH uses open loop power control (slow power control).

>> In which case is it interesting to use beam>> In which case is it interesting to use beam--forming antennas? would it also be forming antennas? would it also be

relevant to implement this feature for PCH?relevant to implement this feature for PCH?

RACH: Random Access Channel

An uplink transport channel that is used to carry control information from the mobile especially at the initial access. It may also carry short user packets. The RACH is always received from the entire cell and is characterized by a limited size data field, a collision risk and by the use of open loop power control (slow power control).

>> Why is it interesting to carry short user packets on RACH in >> Why is it interesting to carry short user packets on RACH in spite of limited data spite of limited data

field and collision risk (instead of using a dedicated channel)?field and collision risk (instead of using a dedicated channel)?

Note: Beam-forming is also called “Inherent addressing of users”: it is the possibility of transmission to a

certain part of the cell.

RACH and FACH are mainly used to carry signalling (e.g at the initial access), but they can also carry

small amounts of data.

When a UE sends information on the RACH, it will receive information on FACH.






1 � 37

3 Radio Channels

3.10 Common Transport Channels [cont.]

DSCH: Downlink Shared Channel

A downlink transport channel shared by several UEs to carry dedicated control or user information. When a UE is using the DSCH, it always has an associated DCH, which provides power control.

CPCH: Common Packet Channel

An uplink transport channel that is used to carry long user data packets and control packets. It is a contention based random access channel. It is always associated with a dedicated channel on the downlink, which provides power control.

⇒ Transfer of signalling and traffic on a shared basis

DSCH and CCPH seem to be symmetrical, but:

� DSCH is on the DL, so that different user data are synchronised with each other (the information

on whether the UE should receive the DSCH or not is conveyed on the associated DCH)

� CPCH is on the UL, so that different user data can NOT be synchronised (the mobile phones are not

synchronised). It may cause big problem of collisions!






1 � 38

3 Radio Channels

3.11 Dedicated Transport Channels

DCH: Dedicated Channel

A downlink or uplink transport channel that is used to carry user or control information. It is characterized by features such as fast rate change (on a frame-by-frame basis), fast power control, use of beam-forming and support of soft HO.

DCH

� It is different from GSM where TCH carries user data (e.g speech frames) and ACCH carries higher

layer signalling (e.g HO commands)

User data and signalling are therefore treated in the same way from the physical layer (although set of

parameters may be different between data and signalling)

� wide range of Transport Format Set permits to be very flexible concerning the bit rate, the

interleaving...

� Fast Power Control and soft HO are only applied on this transport channel.






1 � 39

Control Logical Channels

BCCH PCCH CCCH DCCH

Traffic Logical Channels

DTCH CTCH

BCH PCH RACH FACH DSCH CPCH DCH

Common Transport Channels Dedicated Transport Channels

3 Radio Channels

3.12 Mapping Logical / Transport Channels






1 � 40

3 Radio Channels

3.12 Mapping Logical / Transport Channels [cont.]

Control Logical Channels

BCCH PCCH CCCH DCCH

Traffic Logical Channels

DTCH CTCH

BCH PCH RACH FACH DSCH CPCH DCH

Common Transport Channels Dedicated Transport Channels

According to the slide above and the previous one, we can say state that :

Except BCH and PCH, each type of transport channel can be used for the transfer of either control or

traffic logical channels.






1 � 41

3 Radio Channels

3.13 Physical Channels

RNC

Node B

IubTransport Channels

For the UE point of view, the network is just the physical channels.

There are several kinds of physical channels.

• Channel associated with transport channel

• UTRAN Signaling (mobility management)

• Core Network Signaling (authentication)

• User Traffic (voice)

� There are common and dedicated channels

• Channels not associated with transport channel, the physical signaling.

• Cell Search Selection

• System Information Collection

• Connection Request and Paging Surveillance

These channels and resources allowing the UE to share these channels with other users are the radio resources

We will see later how data from transport channel are processed to be mapped on the physical channels and how a UE uses these channels.

On a cell, all the physical channels are send on the same frequency and on the same time.

It is due to the radio technology, the WCDMA, really different than the one used with the GSM.

Here the physical channels are separated by codes. We will see this point on the next chapter.






1 � 42

3 Radio Channels

3.14 Physical Channel List

Not associated with transport channels

• CPICH: Common Pilot Channel

• PICH: Page Indicator Channel

• P-SCH & S-SCH: Primary & Secondary Synchronization Channel

• AICH: Acquisition Indicator Channel

Common Physical Channels, associated with transport channels

• P-CCPCH & S-CCPCH: Primary & Secondary Common Control Channel

• PRACH: Physical Random Access Channel

• PDSCH: Physical Downlink Shared Channel

• PCPCH: Physical Common Packet Channel

Dedicated Physical Channels, associated with transport channels

• DPDCH: Dedicated Physical Data Channel

• DPCCH: Dedicated Physical Control Channel






1 � 43

3 Radio Channels

3.15 Downlink

Logical Ch

Transport Ch

Physical Ch

AICHNot associated withtransport channels PICH CPICH P-SCH S-SCH

PDSCH S-CCPCH P-CCPCHDPDCH +

DPCCH

DTCH, DCCH CCCH, CTCH

DCH BCHPCHFACHDSCH

Not implemented

yet in Alactel-Lucent

Solution

PCCH BCCH

DPDCH and DPCCH

multiplexed by time

Common Physical ChDedicatedPhysical Ch

Some common transport channels are multiplexed on the same physical channels. Like the FACH and the

PCH on the S-CCPCH.

The FACH is a downlink common channel to carry the traffic and the control data.

The PCH is the Paging channel.

� By the same principles, several DCH (Dedicated channel) belonging by the same user are mapped

on one physical channel, the DPDCH. The DPCCH is its control channel at the physical level.






1 � 44

3 Radio Channels

3.16 Uplink

Logical Ch

Transport Ch

Physical Ch

PRACH PCPCHDPDCH +

DPCCH

DTCH, DCCH CCCH

DCH1 RACHDCH2

CCTrCH

CPCH

DPDCH and DPCCH

multiplexed by

modulation

Dedicated Physical Ch Common Physical Ch

There are less channels in uplink. For the physical channels, there are the dedicated channels (DPDCH)

and the common channels (PRACH).

The PCPCH is not implemented in the Alactel-Lucent Solution.






1 � 45

A physical channel is defined by:

•A carrier• Some codes (see 4.3 and 4.4 part)• A start and stop instant

Physical channels are sent continuously on the air interface between start and stop instants.

3 Radio Channels

3.17 Physical Channels: Structure

15 Time Slots

Radio Frame = 10 ms

N bits (according to the bit rate)

….

1 Time slot = 0.666 ms

After channel coding each transport block is split into radio frames of 10 ms.

The bit rate may be changed for each frame.

Each radio frame is also split into 15 time slots.

But all time slots belong to the same user (this slot structure has nothing to do with the TDMA structure

in GSM).

All time slots of a same TDMA frame have the same bit rate.

Fast power control may be performed for each time slot (1500 Hz).

The number of chips for one bit M is equivalent to the spreading factor. It can easily be computed with

knowledge of N:

In fact the spreading factor must be equal to 4, 8, 16…256.

Consequently it may be necessary to add some padding bits to match the adequate value of spreading

factor (rate matching).






1 � 46

4 UTRAN Radio Protocols






1 � 47


4.1 Radio protocol stack

Layer 3

Control plane User plane

Layer 2/MAC

Layer 1

Transport Channels

Bearers (called RAB in user plane)Access Stratum

SAP

Non Access Stratum

control

control control

PHY

MAC

RRC

Logical Channels

Layer 2/RLC

Radio Bearers

RLC RLCRLC

RLCRLC

RLCRLCRLC

PDCPPDCP

BMCcontrol

control

Layer 2/PDCPLayer 2/BMC

Physical Channels

The radio protocols are responsible for exchanges of signalling and user data between the UE and the UTRAN over the Uu interface

The radio protocols are layered into:

� the RRC protocol located in RNC* and UE

� the RLC protocol located in RNC* and UE

� the MAC protocol located in RNC* and UE

� the physical layer (on the air interface) located in Node-B and UE

Two additional service-dependent protocols exists in the user plane in the layer 2: PDCP and BMC.

Each layer provides services to upper layers at Service Access Points (SAP) on a peer-to-peer

communication basis. The SAP are marked with circles. A service is defined by a set of service primitives.

Radio Interface Protocol Architecture is described in 3GPP 25.301.

(*except a part of protocol used for BCH which is terminated in Node-B)






1 � 48


4.2 Radio Resource Control (RRC)

control

control

control

PHY

MAC

RRC

RLC

BearersCall management

Radio mobility management

Measurement control and reporting

Outer loop power controlRadio Bearers(control plane)

RRC is the brain of the radio interface protocol stack.

Layer 3

control

control

PDCP

BMC

RRC is a protocol which belongs to control plane.

The RRC functions are:

� Call management

� RRC connection establishment/release (initial access)

� Radio Bearer establishment/release/reconfiguration (in the control plane and in the user plane)

� Transport and Physical Channels reconfiguration

� Radio mobility management

� Handover (soft and hard)

� Cell and URA update (see “5.UTRAN/ Mobility Management”)

� Paging procedure

� Measurements control (UTRAN side) and reporting (UE side)

� Outer Loop Power Control

� Control of radio channel ciphering and deciphering

� RRC can control locally the configuration of the lower layers (RLC, MAC...) through Control SAP. These Control services are not requiring peer-to-peer communication, one or more sub-layers can be bypassed.

� See 3GPP 25.331 RRC protocol (over 500 pages!)






1 � 49


4.3 PDCP and BMC Protocols

PDCP (Packet Data Convergence Protocol)

- in the user plane, only for services from the PS domain

- it contains compression methods

In R99 only a header compression method is mentioned (RFC2507).

Why is header compression valuable?

e.g a combined RTP/UDP/IP headers is at least 60 bytes for IPv6, when IP voice service header can be about 20 bytes or less.

BMC (Broadcast/Multicast Services)

- in the user plane

- to adapt broadcast and multicast services from NAS on the radio interface

In R99 the only service using this protocol is SMS Cell Broadcast Service (directly taken from GSM).

See 3 GPP 25.323 (PDCP protocol) and 25.324 (BMC protocol)






1 � 50


4.4 Radio Link Control (RLC)

TrafficLogical

Channels

Radio Bearers(user plane)

Radio Bearers(control plane)

RLC RLCRLC

RLCRLC

RLCRLCRLC

ControlLogical

Channels

Segmentation

Buffering

Data transfer with 3 configuration modes:

- Transparent (TM)

- Unacknowledged (UM)

- Acknowledged (AM)

Ciphering

RLC provides segmentation and (in AM mode) reliable data transfer.

Layer 2/upper part

There is no difference between RLC instances in Control and User planes. There is a single RLC

connection per Radio Bearer.

RLC main functions:

RLC Connection Establishment/Release in 3 configuration modes:

� - transparent data transfer (TM): without adding any protocol information

� - unacknowledged data transfer (UM): without guaranteeing delivery to the peer entity (but can

detect transmission errors)

� acknowledged data transfer (AM): with guaranteeing delivery to the peer entity. The AM mode

provides reliable link (error detection and recovery, in-sequence delivery, duplicate detection,

flow Control, ARQ mechanisms)

ARQ=Automatic Repeat Request (it manages retransmissions)

Transmission/Reception buffer

Segmentation and reassembly (to adjust the radio bearer size to the actual set of transport formats)

Mapping between Radio Bearers and Logical Channels (one to one)

Ciphering for non-transparent RLC data (if not performed in MAC), using the UEA1, Kasumi algorithm

specified in R’99

Encryption is performed in accordance with TS 33.102 (radio interface), 25.413, 25.331(RRC signaling

messages) and supports the settings of integrity with CN (CS-domain/PS-domain)

3GPP 25.322 RLC protocol






1 � 51


4.5 Medium Access Control (MAC)

Transport Channels

(common and dedicated)

Basic data transfer

Multiplexing of logical channels

Priority handling/Scheduling (TFC selection)

Reporting of measurements

Ciphering

MAC can switch a common channel into a dedicated channel if higher bit rate is required (on request of L3-level).

MAC can change dynamically Transport Format (bit rate…) of each transport channel on a frame basis (each 10 ms) without interchanging with L3-level.

MAC provides flexible data transfer.

TrafficLogical

Channels

ControlLogical

Channels

MACLayer 2/lower part

MAC belongs to control plane and to user plane.

MAC main functions:

Data transfer: MAC provides unacknowledged data transfer without segmentation

Multiplexing of logical channels (possible only if they require the same QoS)

Mapping between Logical Channels and Transport Channels

Selection of appropriate Transport Format for each Transport Channel depending on instantaneous

source rate.

Priority handling/Scheduling according to priorities given by upper layers:

� - between data flows of one UE

� - between different UEs

Priority handling/Scheduling is done through Transport Format Combination (TFC) selection

Reporting of monitoring to RRC

Ciphering for RLC transparent data (if not performed in RLC)

3GPP 25.321 MAC protocol






1 � 52


4.6 The Physical Layer

DedicatedPhysical Channels

Multiplexing of transport ch.

Spreading/modulation

RF processing

Power control

Measurements

Physical layer

DedicatedTransport Channels

The physical layer provides multiplexing and radio frequency processing with a CDMA method.

Air Interface

CommonTransport Channels

CommonPhysical Channels

Layer 1

The physical layer belongs to control plane and to user plane.

Physical layer main functions:

� Multiplexing/de-multiplexing of transport channels on CCTrCH (Coded Composite Transport

Channel) even if the transport channels require different QoS.

� Mapping of CCTrCH on physical channels

� Spreading/de-spreading and modulation/demodulation of physical channels

� RF processing (3 GPP 25.10x)

� Frequency and time (chip, bit, slot, frame) synchronization

� Measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power,

etc.)

� Open loop and Inner loop power control

� Macro-diversity distribution/combining and soft handover execution

3GPP 25.2xx






1 � 53

5 Exercises






1 � 54

5 Exercises

5.1 MAC protocol

CCCHPCCH BCCH CTCH DTCHDCCH DTCHBCCH

FACH RACH DSCH

Iur or local

DCH DCH

MAC-d

MAC-c/sh

CPCHFACHPCH

MAC Control

DSCH

Look at this figure and answer the questions on the following paLook at this figure and answer the questions on the following pages.ges.

MAC-b

BCH






1 � 55

5 Exercises

5.1 MAC protocol [cont.]

1. On which logical/transport channels will be mapped:� system information broadcasting� paging� telephony speech� internet browsing at a high bit rate� internet browsing at a low bit rate

Can you imagine a situation where the UE will use 2 DTCHs (or more) at the same time?

2. Guess the meaning of “MAC-b” “MAC-c/sh” and “MAC-d”.

3. Why is there one MAC-d entity on the UE side and several MAC-d entities on the UTRAN side?

4. What is the link between MAC-c/sh and MAC-d for?






1 � 56

5 Exercises

5.1 MAC protocol [cont.]

5. What are the 4 main functions of MAC protocol?

6. MAC can multiplex logical channels only if they require the same QoS: true or false?

7. Which entity is responsible for TFS selection? TF allocation?

8. Will the physical channel configuration be changed(e.g modification of spreading factor) when MAC selects a new TF inside TFS?

9. MAC makes measurement reports to RRC: why is it necessary?






1 � 57

Evaluation

Thank you for answeringthe objectives sheet

Objective: To be able to draw the UTRAN architecture with the protocol stack(radio and Iu) of each network element and to define the channels generated by these protocols.






1 � 58

End of ModuleUTRAN System Description






WCDMA for UMTS9300 W-CDMA


Edition 1

Section 2WCDMA for UMTS





9300 W-CDMA � UA06 R99 Radio PrinciplesWCDMA for UMTS

2 � 2

Blank Page




Document History






2 � 3

Objectives

� To be able to define a Radio Resource in 3G






2 � 4

Objectives [cont.]







2 � 5

Table of Contents

� Context� Historical

� Advantages & Disadvantages

� 3GPP

� Analogy� WCDMA and Restaurant

� Spread Spectrum Modulation� A Code as a Shell against Noise

� Spectrum spreading

� Transmission Chain

� Code & Spreading factor

� Spreading factor & Data Rate

� Spreading factor & Error at reception

� Exercise: Orthogonal Code

� WCDMA, Power Density & Processing Gain

� Code Division Multiple Access� One-cell reuse

� Multiple access

� Spreading: Channelization and Scrambling

� Channelization Codes (Spreading Codes)

� Scrambling codes

� Soft Handover� Introduction

� Scenarios: Softer Handover

� Scenarios: Soft Handover

� Scenarios: Soft Handover inter RNC

� Scenarios: SRNC Relocation

� Soft Handover & Code Management

� Cost & Benefit

� Rake Receiver� Rake Receiver principle

� Rake Receiver and Multi-Service

� Rake Receiver and soft handover

� Rake Receiver and Path Diversity

� Power Control� Why ?

� Different kinds of Power Control

� Open Loop Power Control

� Closed Loop Power Control: Principle

� Closed Loop Power Control: Power Density

� UL Closed Loop PC, in case of Soft Handover

� DL Closed Loop PC, in case of Soft Handover

� Capacity, Coverage & Quality� Links between Coverage, Capacity and Quality

� Improvement Ways

� Typical Values

Page

1 Context 71.1 Historical 81.2 Advantages & Disadvantages 91.3 3GPP 10

2 Analogy 112.1 WCDMA and Restaurant 12

3 Spread Spectrum Modulation 153.1 A Code as a Shell against Noise 163.2 Spectrum spreading 173.3 Transmission Chain 183.4 Code & Spreading factor 193.5 Spreading factor & Data Rate 203.6 Spreading factor & Error at reception 213.7 Exercise: Orthogonal Code 233.7 WCDMA, Power Density & Processing Gain 24

4 Code Division Multiple Access 264.1 One-cell reuse 274.2 Multiple access 284.3 Spreading: Channelization and Scrambling 304.4 Channelization Codes (Spreading Codes) 314.5 Scrambling codes 32

5 Soft Handover 335.1 Introduction 345.2 Scenarios: Softer Handover 355.3 Scenarios: Soft Handover 365.4 Scenarios: Soft Handover inter RNC 375.5 Scenarios: SRNC Relocation 385.6 Soft Handover & Code Management 395.7 Cost & Benefit 40

6 Rake Receiver 426.1 Rake Receiver principle 436.2 Rake Receiver and Multi-Service 456.3 Rake Receiver and soft handover 466.4 Rake Receiver and Path Diversity 47

7 Power Control 497.1 Why ? 507.2 Different kinds of Power Control 517.3 Open Loop Power Control 527.4 Closed Loop Power Control: Principle 537.4 Closed Loop Power Control: Power Density 547.5 UL Closed Loop PC, in case of Soft Handover 557.5 DL Closed Loop PC, in case of Soft Handover 56

8 Capacity, Coverage & Quality 578.1 Links between Coverage, Capacity and Quality 588.2 Improvement Ways 598.3 Typical Values 60






2 � 6









2 � 7

1 Context






2 � 8

1 Context

1.1 Historical

Early 70’sCDMA developed for military field for its great qualities of privacy (low

probability interception, interference rejection)

1996CDMA commercial launch in the US

This system called IS-95 or cdmaOne was developed by Qualcomm and has

reached 50 million subscribers worldwide

2000IMT-2000 has selected three CDMA radio interfaces:

- WCDMA (UTRA FDD)

- TD-CDMA (UTRA TDD)

- CDMA 2000

In the following material we will only refer to WCDMA (UTRA FDD)

See http://www.cdg.org for IS-95

In CDMA field, we have experience of IS-95

IS-95 vocabulary:

� forward channel=downlink

� reverse channel=uplink

� handoff=handover






2 � 9

1 Context

1.2 Advantages & Disadvantages

CDMA is very attractive:

• Better spectrum efficiency than 2G systems

• Suitable for all type of services (circuit, packet) and for multi-services

• Enhanced privacy

• Evolutionary (linked with progress in signal processing field)

BUT:

• Complex system: not easy to configure and to manage

• Unstable in case of congestion

Spectrum efficiency : transmission capacity per spectrum unit (bandwidth), i.e kbit/MHz.

This must not be confused with the traffic capacity.

The spectrum efficiency in UMTS is higher than in GSM (25x200kHz carriers in GSM offering 335 kbps**

while a 5 MHz UMTS carrier offers 400 kbps).

If we factor in densification (frequency reuse pattern), the UMTS traffic capacity is dramatically

increased. According to CDMA Development Group:

� “Capacity increases by a factor of between 8 to 10 compared to an AMPS

� analog system and between 4 to 5 times compared to a GSM system”






2 � 10

1 Context

1.3 3GPP

The 3GPP is the organization in charge of the standardization of the UMTS.

It is made of standardization organization (ETSI in Europe, T1 in USA, ARIB in Japan or CTWS in China …), member of manufacturers and operators.

The UMTS frequency allocations are :

TDD FDD MSS TDD

1900 1980 2010 20251920

MSSFDD

2110 2170 2200

FDD: Frequency Division Duplex

TDD: Time Division Duplex

MSS: Mobile Satellite SystemUplink Downlink






2 � 11

2 Analogy






2 � 12

• Cell

� Restaurant room

2 Analogy

2.1 WCDMA and Restaurant

WCDMA Restaurant Room

• UE

� People at table

• Code

� Language

Enjoy yourmeal !

Code 1

Code 2

Gutenappetite !

Bon appetit !

Bomapetite !

Ues, like people, sendand receive on the same time and the same frequency. Theyare separeted by:

For a table, the conversations of the neighbours

are noise, for a UE it is the same principle:

neighbour conversations are interference

The equivalence are:

� Restaurant room -> Cell

� Table -> UE

� Language -> Code

Here the important point is all the UEs send and receive on the same time and on the same frequency.

The WCDMA is really different because with the GSM, the UEs are separated by the time (TS of TDMA)

and the frequency. Here the UEs are separated with codes applied on the signals.

Another important point is for someone the conversation on a neighbour table is considered like noise. It

is the same principle with the WCDMA, for a user the other UEs generates some noises.






2 � 13

2 Analogy

2.1 WCDMA and Restaurant [cont.]


•Node B

� Steward

Downlink

Who have order this cake

?

????

???Impacts:

•Power Control in DL

•Control Admission

Very important !

Interference level in DL

� problem:

•If some UE use too much power

•If there are too many users in the cell

Enjoy your meal !

COMO ESTAS ?

In downlink,

� In the restaurant, the steward want to ask to every table who have order a cake. If some people

speak to loud, the table at the back of the room can’t hear the question. It is the same case, if

there are too many users in the room.

� In the cell, it is the same principle. If there are too many Ues on the cell or if some Ues use too

much power, the interference level for a UE far from the Node B is too high to allow the UE

decoding the message.






2 � 14

2 Analogy

2.1 WCDMA and Restaurant [cont.]


It is for me !

Who have order this cake

?

QUIERO LA TARTA!!

Es istmeine

Uplink

C’est à la pomme ?

????

At the Node B level:

• If a UE, close to the NB, speak too loud

•If there are too many users

Problem of interference level too high.

The NB can’t decode any

users anymore.

Impacts:

• Power Control in UL

•Admission Control

Very important

In Uplink,

� In the restaurant, a steward can understand all the conversation if he knows all the languages.

� But if on a table, close to him, some one speak to loud the steward can’t understand people on

the other tables. It is the same problem if there are too many people it is too noisy to able to

understand a conversation far from him.

� With the WCDMA, there is the same problem. That means if the cell is too load,

� the interference level at the Node B is too high to be able to decode the weakest signal.






2 � 15

3 Spread Spectrum Modulation






2 � 16


3.1 A Code as a Shell against Noise

The letter ‘A’ represents the signal to transmit over the radio interface.

At the transmitter the height (ie the power) of ‘A’ is spread, while a color

(i.e a code) is added to ‘A’ to identify the message .

At the receiver ‘A’ can be retrieved with knowledge of the code, even if

the power of the received signal is below the power of noise due to the

radio channel.

ReceiverTransmitter

Spreading

Noise

DespreadingRadio Channel






2 � 17


3.2 Spectrum spreading

At the transmitter the signal is multiplied by a code which spreads the signal over a wide bandwidth while decreasing the power (per unit of

spectrum).

At the receiver it is possible to retrieve the wanted signal by multiplying

the received signal by the same code: you get a peak of correlation, while the noise level due to the radio channel remains the same, because

this is not correlated with the code.

But the interference level is too high, it is not possible to decode any

message.

???

f

P

Spreading

Radio channel

Despreading

Interference Level

f

P

f

P

f

P

What is the interference level ?

The interference level is the power received on the UMTS bandwidth used. These interferences are made

of:

� the background noise,

� the messages of the other users,

� the traffic on the neighbouring cells.

Because all the users on a cells use the same bandwidth on the same time, and the users on the other

cells too, the decoding and so the error ratio depend on the interference level.






2 � 18


3.3 Transmission Chain

Air Interface

The narrowband data signal is multiplied bit per bit by a code sequence:

it is known as “chipping”.

The chip rate (fixed) of this code sequence is much higher than the bit

rate of the data signal: it produces a wideband signal, also called spread signal.

At the receiver the same code sequence in phase should be used to

retrieve the original data signal.

Modulator Demodulator

Code Sequence

Data Data

Code sequence

NB-Signal WB-Signal NB-SignalWB-Signal

Code synchronization between the transmitter and the receiver is crucial for de-spreading the wideband

signal successfully.






2 � 19


3.4 Code & Spreading factor

The code is applied on each bit of the user data.

The Spreading Factor, called SF, is the length of this code.

Example: Data to transmit: 1 0 , SF=8.

1

-1

1

-1

Spread data

Code

Coded data

Transm

ission

Receptio

n

Received data,

without error

1

-1

A chip

Chip rate fixed at 3.84 Mchip/s

Code applied

1

-1

1

-1

1

-1

What is the spreading factor?

� It is the number of chips per bit (=chip rate/bit rate).

� The chip rate is linked with the CDMA carrier bandwidth and has a constant value of 3,84 Mcps.

� It is quite easy to match the bit rate of the signal with the CDMA chip rate just by choosing the

adequate spreading factor.

� The higher the spreading factor, the more redundancy you add in the signal and the lower the probability of bit error is by transmitting the signal.

� It is also traduced by the processing gain (see below).

Code synchronization?

� It is difficult to acquire and to maintain the synchronization of the locally generated code signal

and the received signal.

� Indeed synchronization has to be kept within a fraction of the chip time.






2 � 20


3.5 Spreading factor & Data Rate

The chip rate is fixed, 3.84 Mchip/s.

If the SF is divided by 2, the data rate is multiplied by 2 !


Spread data

Code

Coded data

Transm

ission

Receptio

n

Received data,

without error

Code applied

Received

data

Small SF = High data rate

High SF = Small data rate

1

-1

1

-1

1

-1

1

-1

1

-1

1

-1

The Spreading Factor available are 4, 8, 16, 32, 64, 128, 256 in uplink, plus 512 in downling

For signaling at very low bit rate.






2 � 21


3.6 Spreading factor & Error at reception

When an error occurs at the reception, the determination of the bit value is less trivial.


1

-1

1

-1

Signal sent on the air

Signal received with error

Code

SF=8

Zoom on th

e decoded

signal

Decoded data

1

-1

0

The

determination of

the bit value is

based on the area

of the received

signal.

Here is 6 area units over 8






2 � 22


3.6 Spreading factor & Error at reception [cont.]

1

-1

1

-1

Signal sent on the air

Signal received with error

CodeSF=4

Zoom on th

e

decoded sig

nal

Decoded data

1

-1

0

The

determination of

the bit value is

based on the area

of the received

signal.

Here is 2 area units over 4

With a small SF, the signal is more sensitive to errors.

So to have the same error ratio you use more power

If you need a high data rate(video downloading), you

will use a small SF. You will have more errors on your

message. So if you want to

keep the same error ratio,

you will use more power to transmit your message

To keep in mind

Another way to understand this relation is with the redundancy.

� If the SF is small, 4 for example, the useful bit, 0 or 1, is sent just 4 time. The data rate is high.

� If the SF is higher, 64 for example, the useful bit is sent 64 time. The data rate is smaller.

So if an error occurs, it is more significant if the SF is 4 than if the SF is 64.






2 � 23


3.7 Exercise: Orthogonal Code

Here, there is a received signal and two orthogonal codes

Could you apply these codes on the received signal and determinate which code has been used to spread the signal? What could you conclude about the orthogonality?

Received signal

Code 1

Decoded signal

1

Code 1

Code 2

Code 2

1

-1

1

-1

1

-1

1

-1

1

-1

1

-1

Received signal

Decoded signal

2






2 � 24


3.7 WCDMA, Power Density & Processing Gain

•RSSI: Received Signal Strength Indicator

Total received wideband power over 5

MHz including thermal noise

•ISCP (No): Interference Signal Code Power

Interference on the received signal

•RSCP (Ec): Received Signal Code Power

Unbiaised measurement on the received

signal on one channelization code

• Eb : energy per useful bit

• PG : Processing Gain = Eb-Ec (in dB)

Power Gain after despreading. PG= 20 log (SF) f

P

RSSI or Io

ISCP or No

SIR

PG

Eb

RSCP or Ec

At Node B reception level

Wss

Ws

RSSI: This is the total received wideband (UTRA carrier RSSI) power over 5Mhz

including thermal noise. It is estimating the uplink interference at the Node B, and by difference with

the thermal noise, the rise due to traffic and external interference.






2 � 25

Depending on the service, more or less

errors are allowed. UTRAN computes

the error ratio and then set the SIR

required for the service.

What are the modifications on the

diagram if:

•The number of users increases ?

•The SF decreases ?

SIR: Signal Interference Ratio

No

RSCPSFSIR

.=


3.7 WCDMA, Power Density & Processing Gain [cont.]

f

P

RSSI or Io

ISCP or No

SIR

PG

Eb

RSCP or Ec


Wss

Ws






2 � 26

4 Code Division Multiple Access






2 � 27


4.1 One-cell reuse

The area is divided into cells, but the entire

bandwidth is reused in each cell (frequency

reuse of one)

> Inter-cell interference

> Cell orthogonality is achieved by codes

The entire bandwidth is used by each user at the

same time

> Intra-cell interference

> User orthogonality is achieved by codes

The rainbows cells mean that the whole bandwidth (5 MHz) is reused in each cell.

In GSM there is also intra-cell interference when there are 2 (or more) TRXs in the same cell. But it is a

small problem (as each TRX runs on a different frequency)

In CDMA intra-cell interference is an important problem.






2 � 28


4.2 Multiple access

All the users transmit on the same 5 MHz carrier at the same time and

interfere with each other.

At the receiver the users can be separated by means of (quasi-

)orthogonal codes.

Transmitter 2

Spreading 1

Spreading1

Spreading 2 Receiver

Radio ChannelTransmitter 1

The receiver aims at receiving Transmitter 1 only.

Quasi-orthogonal: it is not necessary to have primary colors at the receiver to separate the user. Red and

orange for example can also be distinguished.

Orthogonality between the codes is impossible to maintain after transfer over the radio interface (multi-

path on DL, UEs not synchronized on UL )






2 � 29


4.2 Multiple access [cont.]

If a user transmits with a very high power, it will be impossible for the

receiver to decode the wanted signal (despite use of quasi-orthogonal

codes)

CDMA is unstable by nature and requires accurate power control.

Transmitter 2

Receiver

Radio ChannelTransmitter 1

The receiver aims at receiving Transmitter 1 only.

Spreading 1

Spreading1

Spreading 2

CDMA is instable by nature:

� one user may jam a whole cell by transmitting with too high power

� need for accurate and fast power control

� too many users in one cell would have the same effect

� need for congestion control

A CDMA resource has 2 dimensions: the codes and the power. Obviously the power is the limiting factor ;

the better we can control the power usage, the more capacity (users) we can allocate.






2 � 30


4.3 Spreading: Channelization and Scrambling

2chc

3chc

1chc

scramblingc

The channelization code (or spreading code) is signal-specific: the code

length is chosen according to the bit rate of the signal.

The scrambling code is equipment-specific.

air

interfaceModulator

Spreading consists of two steps:

� The channelization code (also called spreading code) transforms every data symbol into a number

of chips, thus increasing the bandwidth of the signal. The narrowband signal is spread into a

wideband signal with a chip rate of 3.84 Mchips/s.

� The system must choose the adequate spreading factor to match the bit rate of the

narrowband signal.

� The spreading factor is directly linked with the length of the channelization code.

� The scrambling code does not affect the signal bandwidth: it is only a chip-by-chip operation.

� The scrambling code is cell-specific on the downlink and terminal-specific on the uplink.






2 � 31


4.4 Channelization Codes (Spreading Codes)

The channelization codes are OVSF (Orthogonal Variable Spreading Factor) codes:

• their length is equal to the spreading factor of the signal: they can

match variable bit rates on a frame-by-frame basis.

• orthogonality enables to separate physical channels:

UL: separation of physical channels from the same terminal

DL: separation of physical channels to different users within one cell

SF = 1

C ch,1,0 = (1)

C ch,2,0 = (1,1)

C ch,2,1 = (1,-1)

C ch,4,0 =(1,1,1,1)

C ch,4,1 = (1,1,-1,-1)

C ch,4,2 = (1,-1,1,-1)

C ch,4,3 = (1,-1,-1,1)

SF = 4SF = 2 SF = 8

The code tree is shared by several

users (usually one code tree per

cell)

What is a channelization code?

� OVSF (Orthogonal Variable Spreading Factor)

� Length: 4-256 chips according to the spreading factor

� (in downlink also 512 chips is possible to match very low bit rate)

� Number of codes:

� The channelization codes can be defined in a code tree, which is shared by several users.

� If one code is used by a physical channel, the codes of underlying branches may not be used.

� The number of codes is consequently variable: the minimum is 4 codes of length 4, the maximum

is 256 codes of length 256.

� The channelization code (and consequently the spreading factor) may change on a frame-by-

frame basis

How is Code Allocation managed?

� The codes within each cell are managed by the RNC.

� No need to coordinate code tree resource between different base stations or terminals.

� Usually one code tree per cell. If two code trees are used, it is necessary to use the secondary

scrambling code.






2 � 32


4.5 Scrambling codes

The scrambling codes provide separation between equipment:

• UL: separation of terminalsNo need for code planning (millions of codes!)

There are 224 long and 224 short scrambling codes in uplink

• DL: separation of cellsNeed for code planning between cells (but trivial task)

There are only long scrambling codes in downlink

(512 to limit the code identification during cell search procedure)

The long scrambling codes are truncated to the 10 ms frame length.

Only one DL scrambling code should be used within a cell.

Another scrambling code may be introduced in one cell if necessary

(example : shortage of channelization code), but orthogonality between

users will be degraded.

In fact, there are two types of scrambling codes:

Long codes:

� Gold codes constructed from a position wise modulo 2 sum of 38400 chip segments of two binary

sequences (generated by means of 2 generators polynomials of degree 25)

� used with Rake Receiver : the PRACH is constructed from the long scrambling sequences. There

are 8192 PRACH preamble scrambling codes in total, divided into 512 groups of 16 each.

Short codes:

� Length : 256 chips

� used with advanced multi-user detector

� likely to be used later

Refer to Technical Specification 3GPP TS 25.213






2 � 33

5 Soft Handover






2 � 34

5 Soft Handover

5.1 Introduction

Principle: As the UEs are separated by codes, they send and receive data at the same time and on the same frequency and one frequency is used in a set of adjacent

cells, the soft handover is possible.

A UE is in case of Soft Handover when it is linked to several cells at the same time.

So , in downlink, the UE receives several time the same data and combine them to

increase the quality. In Uplink, a Node B can receive the same message from several

cells and combines them to increase the quality.

Soft Handover doesn’t exist in GSM, it is not possible because there are

different frequencies in a set of adjacent cells.

Interest: As the quality of the signal is increased after the reception, it is possible to use less power. That

allows to save the interference level. If this

interference level is too high, it is not possible to

decode the data and the call is drop.






2 � 35

5 Soft Handover

5.2 Scenarios: Softer Handover

Iu

Core Network

Iubs Iubs

Iur

Iu

Serving RNC

Serving RNC (SRNC1): on UL it collects information from the Drift RNC and from its own Node-B and

performs selection of the signal on a best frame quality basis. On DL it duplicates

� Iu-information to Drift RNC and to its own Node-B and recombination of the signal is performed

� by the UE. There may be only one Serving RNC per UE.

Drift RNC (DRNC2): it performs the routing of information from/to the Serving RNC.

� There may be up to 4 Drift RNC(s) per UE.






2 � 36

5 Soft Handover

5.3 Scenarios: Soft Handover

Iu

Core Network

Iubs Iubs

Iur

Iu

Serving RNC

Serving RNC (SRNC1): on UL it collects information from the Drift RNC and from its own Node-B and

performs selection of the signal on a best frame quality basis.

� On DL it duplicates Iu-information to Drift RNC and to its own Node-B and recombination

� of the signal is performed by the UE. There may be only one Serving RNC per UE.

Drift RNC (DRNC2): it performs the routing of information from/to the Serving RNC.

� There may be up to 4 Drift RNC(s) per UE.






2 � 37

5 Soft Handover

5.4 Scenarios: Soft Handover inter RNC

Iu

Core Network

Iubs Iubs

Iu

Serving RNC Drift RNCIur






2 � 38

5 Soft Handover

5.5 Scenarios: SRNC Relocation

Iu

Core Network

Iubs Iubs

Iu

Serving RNC Drift RNCServing RNCIur






2 � 39

In Downlink,

• Scrambling Code

One DL SC per Cell

• Channelization Code

One DL CC per radio link to avoid having the

same code sequence on 2 radio links

In Uplink,

• Scrambling Code

One UL SC per UE

• Channelization Code

One UL CC per service (per physical

channel).

The UE sends one signal which can be

received by several cells.

The UE receives several signals

Conclusion:

5 Soft Handover

5.6 Soft Handover & Code Management

Iu

Core Network

Iubs

Serving RNC

Cell A Cell B

DL SC cellA

DL CC1 user 1

DL SC cellB

DL CC2 user 1

UL SC eqUL CC user






2 � 40

Why do we need soft HO?

Imagine that a UE penetrates from one cell deeply into an adjacent cell:

� it may cause near-far effect

�hard HO is not a good solution, due to the hysteresis mechanism

Better spatial repartition of the power, so lower interference level

Additional resources due to soft HO:

- Additional rake receiver in Node-B

- Additional Rake Fingers in UE

- Additional transmission links between Node-Bs and RNCs

Soft HO provides Diversity (also called Macro-Diversity), but requires

more network resource.

5 Soft Handover

5.7 Cost & Benefit






2 � 41

� Soft Handover execution:

� Soft Handover is executed by means of the following procedures

� Radio Link Addition (FDD soft-add);

� Radio Link Removal (FDD soft-drop);

� Combined Radio Link Addition and Removal.

� The cell to be added to the active set needs to have information forwarded by the RNC:

� Connection parameters (coding scheme, layer 2 information, …)

� UE ID and uplink scrambling code,

� Timing information from UE

� The UE needs to get the following information

� Channelization & scrambling codes to be used

� Relative timing information (Timing offset based on CPICH synchro)

5 Soft Handover

5.7 Cost & Benefit [cont.]






2 � 42

6 Rake Receiver






2 � 43

6 Rake Receiver

6.1 Rake Receiver principle

In a CDMA system there is a single carrier which contains all user signals.

Decoding of all these signals by one receiver is only a question of signal

processing capacity.

A Rake receiver is capable to decode several signals simultaneously in

the so called “fingers” and to combine them in order to improve the quality of the signal or to get several services at the same time.

A Rake receiver is implemented in mobile phones and in base stations.

A Rake receiver can provide:

- multi-service (via handling of multiple physical channels that are

carrying the services)

- soft handover- path diversity

“A single carrier”: in fact each operator may use several carriers of 5MHz each (2 in Germany, 3 in

France)

The rake receiver can only be used with signals on the same carrier.






2 � 44

6 Rake Receiver

6.1 Rake Receiver principle [cont.]

The components of the multi-code signal are demodulated in parallel each

in one “finger” of the Rake Receiver.

The outputs of the fingers:

• can provide independent data signals

• can be combined to provide a better data signal(s)

Delay 1Code Sequence 1

Code Sequence 2 or 3

Code Sequence 2Delay 2

Delay 3

Data 2

1st

Finger

2nd

Finger

3rd

Finger

Data 1

Multi-code signal

Delay Adjustment

Rake fingers are allocated to the peaks at which significant energy arrives. Update rate: tens of ms

Each finger tracks the fast-changing phase and amplitude values due to fast fading and removes them

Rake Receiver resides in both UE and Node-B.

The numbers of fingers for a Rake Receiver is implementation dependant.






2 � 45

6 Rake Receiver

6.2 Rake Receiver and Multi-Service

As a first approach, we can say:

One service, one code! (*)

Multimedia receiverTransmitter

Spreading 1 Despreading 1

Radio ChannelSpreading 2

Despreading 2

>> Which codes make it possible to >> Which codes make it possible to

separate the two signals at the separate the two signals at the

receiver?receiver?

* We will see later that it is also possible to multiplex several services on the same code!

Indeed on a dedicated physical channel (which is identified by its spreading code) a user can multiplex

several services as long as the total bit rate of the services does not exceed the bit rate of the physical

channel.

See subchapter 4 UTRAN/ Physical Layer (Transport Channel Multiplexing)






2 � 46

6 Rake Receiver

6.3 Rake Receiver and soft handover

Soft handover is possible, because the two mobile stations use the same

frequency band. The mobile phone need only one transmission chain to

decode both simultaneously.

Base Station 2

Spreading 1

Despreading 1&2

Spreading 2 Mobile phone

Radio ChannelBase station 1

>> Which codes make it possible to >> Which codes make it possible to

separate the two signals at the separate the two signals at the

receiver?receiver?






2 � 47

6 Rake Receiver

6.4 Rake Receiver and Path Diversity

Natural obstacles (buildings, hills…) cause reflections, diffractions and

scattering and consequently multipath propagation.

The delay dispersion depends on the environment and is typically:

• 1 µs (300 m) in urban areas

• 20 µs (6000 m) in hilly areas

The delay dispersion should be compared with the chip duration 0,26 µs (78 m)

of the CDMA system.

If the delay dispersion is greater than the chip duration, the multipath

components of the signal can be separated by a Rake Receiver.

In this case, CDMA can take advantage of multipath propagation.

What is multipath propagation?

� The signal travels from transmitter to receiver over different paths, due to reflections,

diffractions or scattering. Consequently the same signal arrives at the receiver with a little

delay.

� The chip rate can be considered as the resolution of the CDMA system. It is linked with the 5 MHz

carrier.






2 � 48

6 Rake Receiver

6.4 Rake Receiver and Path Diversity [cont.]

Dispersion > Chip duration

The Rake Receiver can provide path diversity to improve the quality of the signal.

ReceiverTransmitter

Spreading

Direct path

Reflected path

ReceiverTransmitter

Spreading Despreading

Direct path

Reflected path

Dispersion <Chip duration

The Rake Receiver cannot provide path diversity.>> Which codes make it >> Which codes make it

possible to separate the two possible to separate the two

signals at the receiver?signals at the receiver?

Despreading

Multi-path propagation usually reduces the quality of the signal.

But in most cases a Rake Receiver can take advantage of multi-path to improve the quality of the signal.

Indeed the dispersion is often greater than the chip duration.

Note: with IS-95 (cdmaOne), the carrier bandwidth is about 1 MHz and the chip duration is consequently

longer: 1 µs (300 m). Multi-path components can not be separated in urban areas with IS-95.






2 � 49

7 Power Control






2 � 50

SIR

7 Power Control

7.1 Why ?

Iub

Serving RNC

Main Problem : If the interference level is to high, it is not possible to decode the signal.

f

P

ISCP or No

PG

Eb

RSCP or Ec


SIR

In UTRA/FDD, the power control is a key functionality : the users using

� simultaneously the same frequency band interfere each other.

The transmit power must be dynamically adapted in order to

� Enable to reach the quality of service

� Compensate fading occurrences

� Avoid interfering other users (and thus decreasing the system capacity)

Two main power control algorithms can be distinguished:

� Open-loop power control (UL only)

� Closed loop power control (UL/DL)






2 � 51

Physical channels:

• Not associated with transport channels

(Physical signaling)

• Associated with transport channels

• Dedicated channels

• Common channels

7 Power Control

7.2 Different kinds of Power Control

Channel power fixed and set by the

operator

Channel power fixed and set by the

operator

Open Loop Power Control

Closed & Open Loop power control






2 � 52

7 Power Control

7.3 Open Loop Power Control

The Open Loop Power Control is used to set the initial transmit power when:

• The UE requests a RRC Connection,

• The UE sends the first dedicated radio frame,

• The Node B sends the first dedicated radio frame.

Based on CPICH measurements

Based on UE measurement reports

CPICH

• Initial Access

•First dedicated Radio Frame

Measurement reports

•First dedicated Radio Frame

How is Power Control performed ?

� Open loop power control:

� it consists for the mobile station of making a rough estimate of path loss by means of a

� DL beacon signal and adding the interference level of the Node-B and a constant value.

� It’s far too inaccurate and only used to provide a coarse initial power setting of the mobile

� station at the beginning of a connection






2 � 53

Iub

RNC

Outer Closed Loop Inner Closed Loop

• SIR Estimation

• Comparison

between SIRest and

SIRtarget

•Generation of a TCP

command: increase

or decrease

On each Time slot !

(1500 Hz)...

”Power down”

”Power up”

”Power down”

”Power ...”

***

***

SIR target

Error

measurements

The Node-B controls the power of the UE (and vice versa) by performing a SIR estimation (inner loop) and by generating TPC command for each time slot of the radio frame.

The RNC controls parameters of the SIR estimation (outer loop) and set the initial SIR target, defined by the operator and modify it according to the error measurement reports.

Closed Loop Power Control

7 Power Control

7.4 Closed Loop Power Control: Principle

***

***

***

***

Inner Loop (Fast Loop Power Control)

� In UL, the serving cells should estimate signal-to-interference ratio SIRest

� of the received uplink DPCH. The serving cells should then generate TPC commands

� and transmit the commands once per slot according to the following rule: if SIRest > SIRtarget

� then the TPC command to transmit is "0" , while if SIRest < SIRtarget then the TPC

� command to transmit is "1".

� Upon reception of one or more TPC commands in a slot, the UE shall derive a single

� TPC command, TPC_cmd, for each slot, combining multiple TPC commands if more

� than one is received in a slot. TPC_cmd values = +1(power up), -1 (power down), 0

� The step size DTPC is under the control of the UTRAN (value = 1 dB or 2 dB)

� UE shall adjust the transmit power of the uplink DPCCH with a step of DDPCCH (in dB)

� which is given by DDPCCH = DTPC × TPC_cmd.

� The command rate of 1500Hz is faster than any significant change of path loss.

Outer Loop

� The RNC checks the quality of the signal using for example a CRC-based approach

� (Cyclic Redundancy Check) and uses this result to adjust SIR target for the inner loop.

� The big issue is to meet constantly the required quality: no worse and also no better,

� because it would be a waste of capacity.

� The required quality may change with the multi-path profile (related to the environment)

� and with the UE speed.

� The outer loop management is handled by the CRNC because a soft HO may be performed.

� Frequency of the outer loop: 10-100 Hz typically

� Note: in GSM only slow power control is employed (about 2 Hz)






2 � 54

Iub

Assuming a user using a service.

It is initial SIR target is 3dB.

The error ratio required is 0.01 .

Several error ratio reports are between 0.002

and 0.007

How do the SIR target evolve ?

What is the impact on the user or on the system if the estimated SIR is too high ? Too small ?

7 Power Control

7.4 Closed Loop Power Control: Power Density

RNC...

”Power up”

”Power ...”

SIR target

Errormeasurements

ISCP or No

f

P

SIRest

Eb

RSCP or Ec


SIRTarget






2 � 55

What is the behavior of the UE in UL in case of

soft handover ?

• The UE takes in to account all the command

according to the 3GPP

P(t)=P(t-1) + F(TPC1(t) + TPC2(t))

The function F(TPC(t)) is implemented by the UE

manufacturer.

F(TPC(t))=min(TCP1(t), …, TPCi(t))

With i= number of involved Node B

7 Power Control

7.5 UL Closed Loop PC, in case of Soft Handover

Iub

Power up !!!

TPC=1Power down !!!

TPC=-1

???

1 2






2 � 56

Iub

What is the behaviour of the Node B involed

in the call in DL in case of soft handover ?

• The UE sends the same command for all

the Node B involved.

� Node Bs must transmit data with the same

power for a user

• Due to reception errors their power can

shift themselves

� A mechanism, the DL Power Balancing, allows to readjust the transmission power of

the Node B.

� The SRNC selects the best radio link, and

readjust, step by step, the transmission

power.

� P(t) = P(t-1) + Ptpc(t) + Pbal(t)

Power up !!!

TPC=1

Power

up

Power

up

7 Power Control

7.5 DL Closed Loop PC, in case of Soft Handover






2 � 57

8 Capacity, Coverage & Quality






2 � 58

8 Coverage, Capacity & Quality

8.1 Links between Coverage, Capacity and Quality

Example: Increase the quality in UL

How to do ?

• Decrease the error ratio at the Node B level

• So increase the SIR at the Node B level

• So the UEs use more power

Impacts !

• Increase the UL Interference level

• So decrease of the cell size

• And decrease the capacity of the cell.

RNC

Node B

Iub

f

P

SIR

SIR






2 � 59


8.2 Improvement Ways

•AMR speech Codecit enables to switch to a lower bit rate if the mobile is moving out of the

cell coverage area: it is a trade-off between quality and coverage.

•Multipath diversityit consists of combining the different paths of a signal (due to reflections,

diffractions or scattering) by using a Rake Receiver.

Multipath diversity is very efficient with W-CDMA.

•Soft(er) handoverthe transmission from the mobile is received by two or more base stations.

•Receive antenna diversitythe base station collects the signal on two uncorrelated branches. It can be

obtained by space or polarization diversity.

•Base stations algorithmse.g. accuracy of SIR estimation in power control process

The AMR (Adaptive Multi-rate) speech codec:

� offers 8 AMR modes between 4,75 kbps and 12,2 kbps

� is capable of switching its bit rate every 20 ms upon command of the RNC

� is located in the UE and in the transcoder (which is located in the CN)






2 � 60


8.3 Typical Values

Quality: The quality is measured with the Block Error Ratio (BLER). Here some example according different services.

Coverage:

• Dense Urban Cell: about 300 meters

• SubUrban Cell: about 1 km

• Rural Cell: 3 km

Capacity:

The main limitation is the interference level due to the WCDMA technology.

But the system is also limited by capacity processing of the Node B and the RNC, by the codes, and by

the transmission capacity.

0.10.01 0.01

DCCH

0.01

PS384

0.01

PS128

0.01

PS64

0.01 0.001

CS64

0.001

AMR

Target BLER

The capacity depends also on:

� the radio environment (rural, suburban, indoor)

� the terminal speeds

� the distribution of the terminals

� the load of the cell: trade-off capacity/coverage (breathing cells)

Due to all these parameters, it is harder than in GSM to give a typical value of the capacity of a cell.






2 � 61

Evaluation


Objective: To be able to define a Radio Resource in 3G






2 � 62

End of Module






UTRAN_scenario9300 W-CDMA


Edition 1

Section 3UTRAN_scenario





9300 W-CDMA � UA06 R99 Radio PrinciplesUTRAN_scenario

3 � 2

Blank Page




Document History






3 � 3

Objectives

� To be able to build the map of the radio channels(logical, transport and physical channels) from a white paper.






3 � 4

Objectives [cont.]







3 � 5

Table of Contents

� Introduction to UTRAN Scenarios� Introduction

� Radio Channels Mapping� Downlink

� Uplink

� Service Request� System Information Collection

� RRC Connection

� IMSI Attachment & Location Update

� Paging

� RAB Establishment� Admission Control

� Radio Bearer Establishment

� Mobility Management in Connected Mode� Soft HO: Active & Monitoring Set

� Soft HO: Events

� Compressed Mode

� Hard HO: Events on other FDD

Frequencies

� Hard HO: Events on other GSM

Frequencies

� Exercises� Scenario Description

� Downlink

� Uplink

Page

1 Introduction to UTRAN Scenarios 71.1 Introduction 8

2 Radio Channels Mapping 112.1 Downlink 122.2 Uplink 13

3 Service Request 143.1 System Information Collection 153.1.1 P-SCH & S-SCH 163.1.2 CPICH 173.1.3 System Information Broadcast 183.1.4 Procedure 203.1.5 Radio Channel Mapping: P-CCPCH 213.1.6 Cell Selection Principle 22

3.2 RRC Connection 233.2.1 UE Status 243.2.2 Procedure: RRC Connection Establishment 273.2.3 Procedure: RRC Connection: RRC Connection Release 283.2.4 How to contact UTRAN: the PRACH 29

3.3 IMSI Attachment & Location Update 313.3.1 Principles 323.3.2 Procedure: Direct Transfer 33

3.4 Paging 343.4.1 Procedure 1: UE in Connected Mode 353.4.2 Procedure 2: UE in Idle Mode 363.4.3 Paging: PICH & PCH Radio Channels 37

4 RAB Establishment 384.1 Admission Control 394.2 Radio Bearer Establishment 414.2.1 Signaling: RAB Establishment 424.2.2 Signaling: Radio Link Setup 434.2.3 Radio Bearer Mapping 444.2.4 Physical Layer Processing 454.2.5 Radio Channels 464.2.6 Radio Channels: Data Processing 474.2.7 Radio Channels: Transport Channel Multiplexing 484.2.8 Radio Channels: DPDCH/DPCCH Channels 49

5 Mobility Management in Connected Mode 505.1 Soft HO: Active & Monitoring Set 515.2 Soft HO: Events 525.3 Compressed Mode 535.4 Hard HO: Events on other FDD Frequencies 545.5 Hard HO: Events on other GSM Frequencies 55

6 Exercises 566.1 Scenario Description 576.2 Downlink 586.3 Uplink 59






3 � 6









3 � 7

1 Introduction to UTRAN Scenarios






3 � 8


1.1 Introduction

Iub

Serving RNC

CN� Collection of System Information

System Information

RRC Connection

� RRC Connection

� IMSI Attachment

IMSI Attachment

� Paging

Paging

The UE is switched on !

How can it retrieve network parameters to request a service?

On the first part, we are going to see how a UE, after it is just switched on, can be able to request a

service and to answer to a paging message.

So the first step is to retrieve information about the system. Thank to these system information the UE is

able to attach its IMSI and to update its location to the Core Network.

After that the UE can monitor a channel to answer to a paging message or can request itself a service.






3 � 9


1.1 Introduction [cont.]

Iub

Serving RNC

CN

The UE requests a service.

How and in which conditions are the resources required setup ?

� Admission Control

?� RAB Establishment

RAB

When a UE requests a service, the UTRAN must check if it has enough resources to establish new

dedicated channels.

There are after signaling between the UE, the Node B, the RNC and the Core Network to provide to the

UE the transfer of the data at the required QoS.

We will also how the data are mapped on the physical channels.






3 � 10


1.1 Introduction [cont.]

Iub

Serving RNC

CN

The UE uses a service and moves !

How UTRAN can provide the service despite the mobility ?

� A new radio link is added

� Hard Handover on another FDD carrier

� Inter RAT Handover

BSCBTS

UTRAN must provide the transfer of the data at the requested QoS to a moving user. So different kinds of

handover have been defined.

The Soft Handover, the UE can be linked to several cells using the same fraquency.

The Hard Handover inter FDD carrier and the interRAT HandOver between the 3G and the 2G network if

the user loses the 3G coverage.






3 � 11

2 Radio Channels Mapping






3 � 12


2.1 Downlink

Logical Ch.

Transport Ch.

Physical Ch.

AICHNot associated with transport channels PICH CPICH P-SCH S-SCH

PDSCH S-CCPCH P-CCPCHDPDCH +

DPCCH

DTCH, DCCH CCCH, CTCH

DCH BCHPCHFACHDSCH

Not implemented

yet in EvoliumTM

Solution

PCCH BCCH

DPDCH and DPCCH

multiplexed by

timeCommon Physical Ch.Dedicated

Physical Ch.






3 � 13


2.2 Uplink

Logical Ch.

Transport Ch.

Physical Ch.

PRACH PCPCHDPDCH +

DPCCH

DTCH, DCCH CCCH

DCH1 RACHDCH2

CCTrCH

CPCH

DPDCH and DPCCH

multiplexed by

modulation

DedicatedPhysical Ch.

CommonPhysical Ch.






3 � 14

3 Service Request






3 � 15

3 Service Request

3.1 System Information Collection

Principles

•The UE synchronize itself at the

slot on the P-SCH

• UE synchronize itself at the

frame level on the S-SCH and

retrieve a group of 8 Scrambling

codes.

•The UE test the 8 SC on the

CPICH to find the SC of the cell

•The UE decode the BCH channel to read the system information

•The UE select the best cell

Iub

Serving RNC

CN

???

Just after the switch on, the UE can decode only the P-SCH and S-SCH if it is on a covered area






3 � 16


3.1.1 P-SCH & S-SCH

P-CCPCH Radio Frame 10 ms

Slot #0 Slot #1 Slot #14

acpP-SCH

S-SCH acs0

…acp acp

acs2 acs14

The SCH is time-multiplexed with the P-CCPCH (which carries the BCH) and consists of 2 sub-channels.

• The Primary SCH (P-SCH) made of always the slot on all the FDD Cells. The UE uses it to acquire the

slot synchronization to a cell.

•The Secondary SCH (S-SCH) contains a sequence of 15 codes which identifies the Code Group of the

Downlink Scrambling Code (DL SC) of the cell. The UE uses it to acquire the frame synchronization to a

cell and to identify the Code Group of the DL SC.

256 chips

Cell Search Procedure (also called synchronization procedure)

� 3GPP TS 25.214 provides an informative description how it is typically done

� Step 1: slot synchronization

In all the cell of any PLMN, the P-SCH is made of a unique & same primary code sequence of 256

chips repeated at each Time Slot Occurrence. This is typically done with a single matched filter (or

any similar device) to the primary synchronisation code which is common to all cells. The slot timing

of the cell can be obtained by detecting peaks in the matched filter output.

� Step 2: frame synchronization and code-group identification

A S-SCH is made of 15 repetitions of a secondary code sequence of 256 chips (one per Time Slot)

transmitted in perfect synchronization with the P-SCH code sequences. The UTRAN uses 64 distinct

secondary synchronization code sequences (reused in distant cells of the UTRAN). This is done by

correlating the received signal with all possible secondary synchronisation code sequences, and

identifying the maximum correlation value. Since the cyclic shifts of the sequences are unique the

code group as well as the frame synchronisation is determined.

Each secondary code sequence corresponds to a unique group of 8 possible Primary Scrambling

codes

� Step 3: (downlink) scrambling code identification

� The UE determines the (primary) scrambling code used by the found cell through symbol-by-

symbol correlation over the CPICH (pilot) with all codes within the Code Group identified in

the step 2 (8 possibilities).

� Afterwards the P-CCPCH can be detected and the system- and cell specific BCH information

can be read.






3 � 17


3.1.2 CPICH

CPICH (Common Pilot CHannel)

•The pilot carries a pre-defined symbol sequence at a fixed rate.

•It is a reference:

• To aid the channel estimation at the terminal (time or phase reference)

• To perform handover measurements and cell selection/reselection (power reference)

• The UE tests the 8 DL SC of the Group Code. The DL SC which allows to retrieve the pre-define

sequence is the DL SC of the cell.

…Slot #0 Slot #1 Slot #14

Pre-defined symbol sequenceSF=256 Tslot=2560 chips 20 bits

The CPICH has the following characteristic

� The same channelization code is always used for the P-CPICH,

� The P-CPICH is scrambled by the primary scrambling code,

� There is one and only one P-CPICH per cell,

� The P-CPICH is broadcast over the entire cell.






3 � 18


3.1.3 System Information Broadcast

The broadcast system information:

• May come from CN, RNC or Node-B.

• Contains static parameters (Cell identity, supported PLMN types...) and dynamic

parameters (UL interference level...).

• Is arranged in System Information Blocks (SIB), which group together elements of

the same nature.

Some exemple:

•SIB1: Core Network Information

•SIB3: Cell Selection, Access Restriction

•SIB7: UL Interference

•SIB11: Measurement

CN

LA, RA …

DL SC, Power Control info

UL interference level

Example of SIB:

� MIB: Master Info Block (structure & scheduling of SIBs)

� SIB 1: NAS System Information + Timer

� SIB 2: URA (not supported) +Timer

� SIB 3: Cell Selection/Reselection and Access Restriction

� SIB 5: Common channel Information (P-CCPCH, S-CCPCH, RACH) and AICH/PICH

power offset

� SIB 7: UL Interference and PRACH parameter SIB 11:Measurements

� SIB 18:PLMN Identity of neighboring cells






3 � 19


3.1.3 System Information Broadcast [cont.]

The broadcast system information can be carried on BCH which is transmitted permanently over

the entire cell.

Transport Ch.

Logical Ch.

Physical Ch.

BCCH

BCH

P-CCPCH

The broadcast system information is made of 128 periodic radio frame. So its period is 1280 ms.

There are a Master SIB or MIB and several SIB (System Information Block) organised by domain.

Frame #0 Frame #1 Frame #2

Frame #i-1 Frame #i Frame #i+1

Frame #125 Frame #126 Frame #127

MIB SIB3 SIB11

SIB5 SIB7 MIB

SIB5SIB11 SIB7

…

……

…

Thanks to this channel, the UE is able to retrieve information allowing the request of a RRC connection like the Channelization code used on the uplink common channel

Three parameters are used to set the position of each SIB on the cycle.

SIB_POS: it is the position of the SIB on the cycle (#0 for the MIB for instance)

� SIB_REP: it is the repetition of the SIB on the cycle (the MIB is repeated several time on the cycle.

� SIB_OFF: If one Radio Frame is not enough to send all the data for a SIB, the rest of the SIB can be

send on another radio frame. For example, 2 radio frame after the first one. It is the SIB_OFF.






3 � 20


3.1.4 Procedure

System Information Update Request

Master/Segment Info Block(s), BCCH

modification time

Master/Segment Info Block(s)

System Information (BCCH:BCH)

UE Node-B RNC

RRC RRC

NBAP

CN


System Information (BCCH:BCH)RRC RRC


System Information (BCCH:BCH)RRC RRC

System Information Update Response

NBAP NBAP

>> Why does RRC protocol >> Why does RRC protocol

terminate at Nodeterminate at Node--B for B for

BCH (not at RNC)?BCH (not at RNC)?

NBAP






3 � 21


3.1.5 Radio Channel Mapping: P-CCPCH

The Primary CCPCH carries the BCH, which provides system- and cell-

specific information (e.g set of uplink scrambling codes)

The P-CCPCH is a fixed rate 30 kbps DL physical channel, which provide a

timing reference for all physical channels (directly for DL, indirectly for

UL).

CCPCH is scrambled under the Primary Scrambling code.

Slot #0 Slot #1 Slot #13 Slot #14Slot #i

SCH

Tslot=2560 chips

20 bits

256 chips

Payload of 18 bits

The P-CCPCH is time multiplexed with the SCH which is transmitted during the first 256 chips.

P-CCPCH timing is identical to that of SCH and CPICH (see 3GPP 25.211).

The P-CCPCH contains no layer 1 information.

Even if the PCCPCH is not transmitted during the 256 first chips of each slot (SCH), the scrambling code is

aligned with the PCCPCH frame boundary, i.e the first complex chip of the PCCPCH frame is multiplied

with chip number zero of the scrambling code.

The Secondary CCPCH, which is used to carry FACH and PCH information, is scrambled under the Primary

scrambling code as well.






3 � 22


3.1.6 Cell Selection Principle

Now, the UE can read the BCH of one cell.

But this cell is not necessary the best because

the SCH has been chosen randomly.

The UE compares the cells to be camped on the

best one.

There are 2 criterion:

• QRxLev, from the CPICH RSCP, to estimate the

reception level.

• Qqual, from the CPICH Ec/No, to estimate the

quality of reception. It takes in account the

interference level.

When a UE is not connected, like here, and is

moving, it has to reselect regularly the best cell

for itself. To protect some cells, it is possible to

facilitate or not the selection of one cell.

Iub

RNC

CN

???

Aim : find a suitable cell to be camped on

The Cell selection criterion is defined in 3GPP TS 25.304 as:

� Squal>0 with Squal=Qqualmeas - Qqualmin

� Srxlev>0 Srxlev= Qrxlevmeas – Qrxlevmin - Pcompensation

Parameters :

� Qqualmeas: defines the quality of the cell

� Measured CPICH Ec/N0

� Qqualmin: defines the threshold for the quality of the cell

� Configurable in each cell independently

� Range: -24 dB to 0 dB (step 1 dB)

� Qrxlevmeas : defines the cell Rx Level value

� Measured CPICH RSCP

� Qrxlevmin : defines the minimum required RX level of the cell

� Configurable in each cell independently

� Range: -115 dBm to -25 dBm

� Pcompensation:

� Parameter to take in account the UE capacity






3 � 23

3 Service Request

3.2 RRC Connection

Why?The UE is switched on and has selected a cell.

The UE is in idle mode.

•UTRAN doesn’t know anything about this UE.

•The UE has neither UTRAN identifier nor

Scrambling and Channelization code.

� The UE can’t exchange any data with UTRAN.

To be known by UTRAN and to use dedicated radio

resources, the UE has to be RRC connected.

After, the UE can attach its IMSI or update its

location to the Core Network and can request a

service

Iub

RNC

CN

RRC Connected






3 � 24

3.2 RRC Connection

3.2.1 UE Status

UE

detached

UE

in idle mode

UE

in connected

mode

RRC Connection Release

RRC Connection Establishment

out of coverage

“just after switch on” process

Including Cell search procedure

Just after the switch on, the UE has to attach its IMSI. Thanks to his procedure the Core Network

knows, the UE is on the network and where it is located at the Location or routing area level.

Several sub-status in the connected

mode

To attach its IMSI and update its location the UE has to be in connected mode, so it

has to request a RRC Connection

Just after switch on” process contains:

� Cell selection (including cell search procedure)

� PLMN selection

� Attachment procedure (see “Appendix” for more details)

The UE must enter the connected mode to transmit signalling or traffic data to the network

What is the relationship with the states of the mobile phone in GSM?

� The two GSM states, idle mode and connected mode, are similar to idle mode and cell_DCH state in

UMTS.

What is the relationship with the states of the mobile phone in GPRS?

� There is no correspondence between GPRS states (idle, standby and ready) and UMTS states.

� Indeed there is no notion of connection on GPRS.






3 � 25

3.2 RRC Connection

3.2.1 UE Status [cont.]

Cell DCH

Cell FACH

URA PCH

Cell PCH

UE

in idle

mode

UE in connected

mode

Cell_DCH state

Signalling and traffic data

dedicated to the UE (mapped

on DCCH and DTCH

respectively) are carried on

DCH transport channel

Cell_FACH state

Signalling and traffic data

dedicated to the UE (mapped

on DCCH and DTCH

respectively) are carried on

RACH (uplink) and FACH

(downlink) transport channels

Cell_DCH ⇒⇒⇒⇒Cell_FACHNo traffic UL/DL at expiry of timer

Cell_FACH ⇒⇒⇒⇒Cell_DCHTraffic volume UL/DL too large

The initial state of the UE is determined by the DCCH established during RRC connection establishment:

� if the DCCH is mapped on a DCH, the UE is in cell_DCH state

� if the DCCH is mapped on RACH/FACH, the UE is in cell_FACH state

The UE can move from one state to another during the time of the RRC connection.

� Transitions between states are:

� based on traffic volume measurements and network load

� always triggered by UTRAN signalling

� Note: in cell_DCH state, the DSCH transport channel can also be used.






3 � 26

3.2 RRC Connection

3.2.1 UE Status [cont.]

Cell_PCH state

No transmission of signalling and

traffic data dedicated to the UE

(no DCCH and no DTCH)

But the RRC connection is still

active (UTRAN keeps RNTI for UE)

and UE location at a cell level.

- a DCCH (and possibly a DTCH) can

be reestablished very quickly (this

procedure is initiated by sending a

paging signal PCH)

URA_PCH state

Very similar to cell_PCH state

UTRAN keeps the location of the UE at

the URA level (set of UMTS cells)

Cell_PCH ⇒⇒⇒⇒ Cell_FACH ⇒⇒⇒⇒URA_PCHToo many cell reselections

Cell_FACH ⇒⇒⇒⇒Cell_PCHNo traffic UL/DL at expiry of timer 2

Cell/URA_PCH ⇒⇒⇒⇒ Cell_FACHIncoming DL or UL traffic

Cell DCH

Cell FACH

URA PCH

Cell PCH

UE

in idle

mode

UE in connected

mode

URA: UTRAN Registration Area (a small set of cells)

Cell_PCH and URA_PCH states are needed for non real time services to optimise usage of codes and

battery consumption. It would not be efficient to allocate permanently a DCH which would be used a

very low percentage of time (Web application for example)

What is the difference between idle mode, Cell_PCH and URA_PCH states?

In idle mode the location of the UE is not known by the UTRAN, but only by the CN at a Location Area

(LA) or Routing Area (RA) level (LA and RA and sets of cells larger than URA.

The paging message PCH must hence be sent in a LA or in a RA when the UE is in idle mode, whereas it

only needs to be sent in a cell in Cell_PCH state or in an URA when the UE is in URA_PCH state (hence

the paging procedure is much faster).






3 � 27

3.2 RRC Connection

3.2.2 Procedure: RRC Connection Establishment

Initial UE identity, Establishment cause, Initial UE capability

1. RRC Connection Request (CCCH:RACH)

UE

RRC RRC

3. Radio Link Establishment

Initial UE identity, RNTI, capability update requirement, TFS, TFCS, frequency, UL

scrambling code, power control info

4. RRC Connection Setup (CCCH:FACH)RRC RRC

Integrity information, ciphering information

5. RRC Connection Setup Complete (DCCH:RACH or DCH)RRC RRC

2. Allocate RNTI, Select Level

1 and Level 2 parameters

(e.g. TFCS, scrambling code)

>> Can the UE send user information (e.g voice call) after compl>> Can the UE send user information (e.g voice call) after completing this stage?eting this stage?

Node-B RNC

1. UE initiates set-up of an RRC connection

� Initial UE identity: e.g TMSI

� Establishment cause: e.g traffic class

2. RNC decides which transport channel to setup (RACH/FACH or DCH) and allocates

� RNTI (Radio Network Temporary Identity) and radio resources (e.g TFS, TFCS, scrambling codes) for

this RRC connection.

3. A new radio link must be setup.

� This is done via a signalling procedure between RNC and Node-B which is managed by NBAP protocol

(see “Procedure D” for more detail).

4. Logical, transport and physical channel configuration are sent to the UE.

5. RRC Connection Setup Complete message is sent:

� on RACH in case of RRC connection on RACH/FACH (cell_FACH state)

� on DCH in case of RRC connection on DCH (cell_DCH state)






3 � 28

Node-B(DRNC)

SRNCDRNCNode-B(SRNC)

3.2 RRC Connection

3.2.3 Procedure: RRC Connection: RRC Connection Release

RRC RRC4. RRC Connection Release (DCCH:DCH )

Cause

RANAP RANAP

1. Iu Release

Command

Cause

RANAP RANAP

2. Iu Release

Complete

-

3. ALCAP Iu Bearer Release

RRC RRC5. RRC Connection Release Complete (DCCH:DCH )

-

6. Radio Link Deletion



UE CN

In this example, the UE is in macro-diversity on two Node-Bs from two different RNCs. Therefore the UE

could only be in cell_DCH state (soft HO is only possible on DCH)

1. The CN initiates the release of RRC connection

2. -

3. SRNC initiates release of Iu Bearer using ALCAP protocol

4. -

5. -

6. SRNC initiates release of radio link (for Node-B of SRNC) using NBAP protocol

7. SRNC requires release of radio link (for Node-B of DRNC) to DRNC using RNSAP protocol

8. DRNC initiates release of radio link (for Node-B of DRNC) using NBAP protocol






3 � 29

3.2 RRC Connection

3.2.4 How to contact UTRAN: the PRACH

For the initial access, the UE has to use a common

uplink channel called the PRACH

Every UE use this channel to request a connection. If

2 UEs request on the time there is collision, and UTRAN receives nothing.

To manage this problem, the UE sends a first

message called preamble until it receives a response

on a downlink channel called AICH.

After the response on the AICH, the UE sends its

message (the request) on the PRACH. Hello !

Iub

RNC

Preamble on the PRACH

Yes ! Response on the AICH

…HELLO!I need a connection

Message part

PRACH= Physical Random Access Channel

AICH= Acquisition Indicator channel






3 � 30

3.2 RRC Connection

3.2.4 How to contact UTRAN: the PRACH [cont.]

The first preamble is sent with the power P.

The UE resends a preamble until it receives a response on the AICH.

At each time, it increases the power of the preamble by the Power Offset parameter (PO)

UTRAN can’t receive its preamble if:

• The power is not enough high

• There is a collision with another user.

In the message part, there is the RRC connection request.

Prea

mble

Prea

mbleMessage part

DPp,mPO

Reception of

AICH

PO

P

PRACH channel






3 � 31

3 Service Request

3.3 IMSI Attachment & Location Update

HLRSGSNMSC/VLR

MSC/VLR SGSN

Iub

RNC

The UE has selected a cell.

It had to declared its identity and its

location (LA & RA) to the Core Network.

So, it requests a RRC connection to send to

the Core Network information about its

situation.

The parameters are mainly the LA, the RA and its IMSI

Initial Attachment

In the selected PLMN, the UE:

� selects the best cell according to radio criteria I

� initiates attachment procedure on the selected cell

During the attachment procedure (called IMSI attach for CS domain, GPRS attach for PS domain), the UE

indicates its presence to the PLMN for the purpose of using services:

� authentication procedure

� storage of subscriber data from the HLR in the VLR (or in the SGSN for PS domain)

� allocation of the TMSI (P-TMSI for PS domain)

The result of the procedure is notified to the UE:

� if successful, the UE can access services

� if it fails, the UE can only perform emergency calls

LA=Location Area= Set of cells for the CS CN

RA= Routinf Area= Set of cells for the PS CN






3 � 32


3.3.1 Principles

When camping on a cell, the terminal must register its LA and/or its RA.

When the terminal moves across the network, it must update its LA (RA) which is stored in VLR

(SGSN) in the Core Network.

LA (RA) Update is performed periodically or when entering a new LA (RA).

HLRSGSNMSC/VLR

Location Area

(LA)Routing Area

(RA)MSC/VLR SGSN

LA and RA are managed on an independent way, but a RA must always be included in one LA (and not be

divided into several different LAs).

� LA update is performed by the NAS layer MM (Mobility Management) located in UE and in MSC.

� RA update is performed by NAS layer GMM (GPRS Mobility Management) located in UE and in SGSN.

In the Core Network, the location information is stored on databases:

� HLR (Home Location Register)

� It stores the master copy of user’s service profile, which consists of information on allowed

services, forbidden roaming areas,… and which is created when a new user subscribes to the

system.

� The HLR also stores the serving system (MSC/VLR and/or SGSN) where the terminal is located.

� VLR (Visitor Location Register)

� It serves the terminal in its current location for CS services and holds a copy of the visiting

� user’s service profile.

� It stores the Location Area (LA) where the terminal is located.

� SGSN (Serving GPRS Support Node)

� It serves the terminal in its current location for PS services and holds a copy of the visiting

� user’s service profile.

� It stores Routing Area (RA) where the terminal is located.






3 � 33


3.3.2 Procedure: Direct Transfer

RANAP RANAP1. Direct Transfer

CN Domain Indicator, NAS PDU

RRC RRC

2. Downlink Direct Transfer

(DCCH:FACH or DCH)

NAS message

UE Node-B SRNC CN

Use mainly for the IMSI attachment, location update and the authentification between the UE and

the Core Network

RANAP RANAP2’. Direct Transfer

CN Domain Indicator, NAS PDU

RRC RRC

1’. Uplink Direct Transfer

(DCCH:RACH or DCH)

CN node indicator, NAS message

UE must be in cell_FACH or in cell_DCH states.






3 � 34

3 Service Request

3.4 Paging

Core Network

Called number

HLRMSC/VLR MSC/VLR

Location Area

Some one is calling

me, I request a RRC

connection

Principle

Paging message with the IMSI of the

called UE

Iub

RNC

Iub

RNC

Iub

RNC

If the UE is in idle mode. UTRAN doesn’t know them and can just forward the paging message coming

from the Core Network to all the cell belonging to the Location ou Routing Area.

The UE monitors periodically a channel to check if it is paged or not.

If the UE is connected the Core Network knows the Serving RNC of the UE and sends the paging message

just to this RNC.

The RNC knows the UE uses the dedicated or common channel to send the paging message.






3 � 35

3.4 Paging

3.4.1 Procedure 1: UE in Connected Mode

RANAP RANAP1. Paging

CN Domain Indicator, UE identity, Paging cause

RRC RRC2. Paging Type 2 (DCCH:FACH or DCH)

In this case the UE is already connected and is using a service (voice call, web-browsing …).

The Core Network knows the situation of the UE and mainly its Serving RNC. The CN

contacts directly the Serving RNC.

The RNC doesn’t use the PCCH and the PCH but the channel used for the UE, dedicated or

common, according to the status of the UE.

UE Node-B SRNC CN

UE is in cell_FACH or in cell_DCH states:

1. CN initiates the paging of a UE to Serving RNC

2. Paging of UE with Paging Type 2 (on DCCH) using the existing RRC connection






3 � 36

3.4 Paging

3.4.2 Procedure 2: UE in Idle Mode

RRC RRC2. Paging Type 1 (PCCH:PCH)

RRC RRC2. Paging Type1 (PCCH:PCH)


CN Domain Indicator, UE identity, Paging cause


Idem

When the is in idle mode, UTRAN doesn’t know where it is located and the Core Network knows

its location at the LA or RA level. UTRAN uses the PCCH and the PCH radio channels.

UE 1 Node-B1UE 2 Node-B2 RNC1 RNC2 CN

UE is in idle mode:

1. CN initiates the paging of a UE over a LA (RA in PS domain) spanning, for example, two RNCs.

2. Paging of UE with Paging Type 1

LA: Location Area, RA: Routing Area (see subchapter “5.8 Mobility Management”)

A similar procedure applies to UE in cell_PCH or in URA_PCH states.






3 � 37

3.4 Paging

3.4.3 Paging: PICH & PCH Radio Channels

The UE doesn’t watch the S-CCPCH.

It watches the PICH (Page Indicator

Channel) at regular and defined

interval and look for its PI, for

Paging Indicator.

The PI is based on the IMSI. Several

UEs can have the same PI.

When the UE find its PI on the

PICH, it watches the S-CCPCH to

check if it is for it and what is the

cause.

Then it requests on RRC connection

to have a RAB.

Transport Ch

Iub

RNC

PICHS-CCPCH

PCH

PCCH Logical Ch

Physical Ch

MAC

Physical layer

In RNC

In Node B

PICHS-CCPCH

Paging message

PI

PI

PI

...

The period of the cycle is between 4 and 4096 radio frames. That means the UE can monitor the PICH

every X seconds, with X between 40 ms and 40,96 seconds. If the period is too short the UE uses too

much power if the period is 40 s, the delay is really long.

It is a trade-off between the delay and the consumption.

To determine the radio frame number into the cycle and the Paging Indication, the UE uses its IMSI and

others parameters send on the SIB.






3 � 38

4 RAB Establishment






3 � 39

4 RAB Establishment

4.1 Admission Control

According to the previous part “WCDMA in UMTS”, if the interference level at the Node B level is

too high, the Node B can’t decode all the signal. The size of the cell decreases. The interferences

are due to several causes:

• The radio environment and the load of the adjacent cells,

• Some users use too much power, the power control manages this problem,

• There are too many users on the the cells

� UTRAN has to check if there is enough UL radio resource

Iub

RNC

f

P

ISCP = NoSIR

PG

Eb

RSCP = Ec


SIR too small to retrieve the message

2 others questions before adding a new user : Is there sufficient DL radio resource andsufficient processing resources ?

If the RAC has not been passed,

� For CS services, the call can’t be established.

� For PS services, the UTRAN may try assigning a RB with a lower bit rate. There are different level of

bit rates than can be used a given requested RAB. The Node B tries to assign first the highest, and

then goes to the lower rates, as long as the RAC rejects the Radio Link Reconfiguration.






3 � 40

4 RAB Establishment

4.1 Admission Control [cont.]

� Is there sufficient UL Radio Resource -> Rx RAC

If UL interference level + estimated new user contribution < threshold

Then Rx RAC ok

� Is there sufficient DL Radio Resource -> Tx RAC

If Total DL Tx Power + estimated new user contribution < threshold

Then Tx RAC ok

� Is there sufficient processing resource -> Processing RAC

3 main points are checked:

• the channelization codes

•The DSP (in BBs) load

•The number of user and radio links limited respectively to 64 users and 90 RLs

RAC = Radio Access Control






3 � 41

4 RAB Establishment

4.2 Radio Bearer Establishment

We have seen how a UE, after the switch on, can collect system information, update its

location, request a RRC Connection and a service, can be paged and how UTRAN allows it to

use services. Now how is established the RAB ?

Signaling

Core NetworkIub

Node B

RNC

UTRAN

RABRadio Bearer

Logical Channel

RLC

Transport Channel

MAC

Physical Channel

Phy.

RLC Mode: Tr., UM or AM and retransmission parameter for AM

TTI, TFS, TFCS, CRC, FEC, Coding Rate, Rate Matching

Frequency, Power, Channelization & Scrambling codes

RRC

Configured by

Iu Bearer RAB







3 � 42


4.2.1 Signaling: RAB Establishment

RANAP RANAP1. RAB Assignment Request

RAB parameters, User plane mode, Transport Address, Iu

Transport association

2. ALCAP Iu Data Transport Bearer Setup

3. Radio Link Establishment

RRC RRC4. RB Setup (DCCH:FACH or DCH )

TFS, TFCS...

RRC RRC

5. RB Setup Complete (DCCH:RACH or DCH )

-

RANAP RANAP6. RAB Assignment Response

-

The UE is RRC connected and has requested a service.

UE Node-B SRNC CN

Can the UE send user information (e.g voice call) just after Radio Access Bearer establishment?

YES : At the end of this signaling procedure, a RAB has been assigned to the UE to carry user information.

The RAB is mapped on the RB which has been set up. The RB is mapped on DTCH: RACH/FACH or DCH.






3 � 43


4.2.2 Signaling: Radio Link Setup

Cell id, TFS, TFCS, frequency, UL scrambling code, power control info

Radio Link Setup RequestNBAP NBAP

Signaling link termination, transport layer addressing info

Radio Link Setup ResponseNBAP NBAP

Downlink synchronisationIub-FP Iub-FP

Uplink synchronisationIub-FP Iub-FP

Start RX

Start TX

>> Are NBAP, ALCAP and RRC messages carried on the same transpor>> Are NBAP, ALCAP and RRC messages carried on the same transport bearers on Iub?t bearers on Iub?

ALCAP Iub Data Transport Bearer Setup

Node-B SRNC


This procedure is used in many RRC procedures, e.g RRC connection establishment (Procedure C1), Radio

Bearer Set-up (Procedure F1), soft HO (Procedure G)…

In this procedure:

� a radio link is set up by the RNC on the Node-B side using the NBAP protocol

� (a similar task is performed on the UE side using RRC protocol, see e.g. procedure C1)

� a terrestrial link (AAL2 bearer) is setup on Iub interface using ALCAP protocol






3 � 44


4.2.3 Radio Bearer Mapping

We have seen how a UE, after the switch on, can collect system information, update its

location, request a RRC Connection and a service, can be paged and how UTRAN allows it to

use services. Now how are established the RAB ?

Core NetworkIub

Node B

RNC

UTRAN

RABRadio Bearer

Logical Channel

RLC

Transport Channel

MAC

Physical Channel

Phy.

RLC Mode: Tr., UM or AM and retransmission parameter for AM

TTI, TFS, TFCS, CRC, FEC, Coding Rate, Rate Matching

Frequency, Power, Channelization & Scrambling codes

RRC

Configured by

Iu Bearer RAB







3 � 45


4.2.4 Physical Layer Processing

Convolutional coding,

Turbo coding

10 ms frame duration

15 time slots

CCtrCH

DPDCH, DPCCH, PRACH...

Channelization codes

Scrambling codes

QPSK

Channel Coding

Radio Frame Segmentation

Transport Channel Multiplexing

Physical Channel Mapping

Spreading

Modulation

Physical Channels

spread over 5 MHz bandwidth

Layer 1

The physical layer belongs to control plane and to user plane.

Physical layer main functions:

� Multiplexing/de-multiplexing of transport channels on CCTrCH (Coded Composite Transport

Channel) even if the transport channels require different QoS.

� Mapping of CCTrCH on physical channels

� Spreading/de-spreading and modulation/demodulation of physical channels

� RF processing (3 GPP 25.10x)

� Frequency and time (chip, bit, slot, frame) synchronization

� Measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power,

etc.)

� Open loop and Inner loop power control

� Macro-diversity distribution/combining and soft handover execution






3 � 46


4.2.5 Radio Channels

Assuming a UE a video call service. What happens in Uplink ?

RLC

MAC

Physical Layer

Radio Bearer

Logical Ch. DTCH

Transport Ch. DCH

Physical Ch. DPDCH/DPCCH

RLC parameters

RAB :64 kbps

MAC parameters

Mode : Transparent because it is a real time service

CRC = 16 bits, FEC = Turbo Code Coding Rate = 1/3, TTI= 20 ms,

TFS=(0*640, 2*640 bits)

640

640

640

640

640

640

TTI

How many radio frame are necessary to send all this data ?

CN

UE

The RB 20 (1st column ) corresponds to the Video Call.






3 � 47


4.2.6 Radio Channels: Data Processing

Assuming a UE a video call service. What happens in Uplink ?

#1 #2

#1 #2

Transport

Blocks

CRC attachment

Tr Bl concatenation

Turbo coding (1/3)

Tail Bit Attachment

1 st interleaving

Radio Frame

Segmentation

Rate matching

640 bits 16

(640+16)*2=1312 bits

1312*3=3936 bits

1312*3=3936 bits

6

3942 bits

#1 #2

1971 1971

#1 #2

1971 +Nrm 1971 +Nrm

Can you deduce the SF ?

And the value of Nrm ?

First, the 16 CRC bits are added at each transport block.

Then the transport block are concatenated.

The turbo coding consist of adding a lot of redundant bits to be able to detect and correct errors.

Before the interleaving some bits are added. The purpose of the interleaving is to avoid to have big

packet of errors at the reception.

Finally the data are segmented by 2, because the TTI=20 ms and a radio frame is 10 ms.

At the end to fill the radio frame, Nrm bits are added.






3 � 48


4.2.7 Radio Channels: Transport Channel Multiplexing

Assuming a UE a video call service and on the same time sends on a e-mail.

How can it be possible to send 2 different services on the same physical channel ?

Several transport channels can be time-coordinated to be multiplexed on a CCTrCH

before mapping on one physical channel

MAC

TFC Selection

L1

TrCH Multiplexing

Phy. Ch. Mapping

CCTrCH

Physical Channel

DCH1 DCH2

Example:

TFS (DCH1)={(0*640); (4*640)}

TFS(DCH2)={(1*0); (1*39); (1*42); (1*55); (1*65)}

TFCS={(0*640); (1*0)}; {(0*640); (1*39)}; {(0*640); (1*42)}; {(0*640);

(1*55)}; {(0*640); (1*65)}; {(1*640); (1*39)}; {(1*640); (1*42)}

MAC selects TFC inside TFCS.

There is one TFCS per CCTrCH

Transport Format

Transport Format Combination

TFS= Transport Format Set

TFCS=Transport Format Combination Set

TF=Transport Format






3 � 49


4.2.8 Radio Channels: DPDCH/DPCCH Channels

Uplink

Downlink



Data : user data, RRC Signaling & NAS Signaling DPDCH

DPCCH Pilot TFCI FBI TPC

Multiplexed by the modulation

Data1 TPC Data2 TFCI Pilot

DPDCH DPCCH DPDCH DPCCH DPCCH

Time-multiplexed

Why are DPDCH and DPCCH time-multiplexed in DL(and not transmitted simultaneously as in UL)?

Discontinuous transmission can cause audible interference to audio equipment close to the terminal (e.g

hearing aids), which is a disturbance for user.

In UL the transmission is always continuous, because there is at least the DPCCH which is transmitted.

The user will not be disturbed.

In DL the transmission may be discontinuous, but it is no problem (no user at the base station).

Note: The downlink DPDCH/DPCCH physical channels are called the DPCH physical channel.






3 � 50

5 Mobility Management in Connected Mode






3 � 51


5.1 Soft HO: Active & Monitoring Set

Iub

RNC

The RNC manages the Active Set and builds the Monitoring Set.

The Monitoring Set is built from the

information of topology and design in the

RNC.

The Active Set is managed from the event

send by the UE to the RNC.

Cell in the Active Set

Cell in the Monitoring Set

The maximum number of cells in the monitoring set is 32.

The maximum number of cells in the active set is set from the Office Data, between 3 and 6.

The monitored set is built for each UE by the RNC from the neighboring list. The RNC selects the best

cells in this list for the monitored cells.






3 � 52


5.2 Soft HO: Events

Iub

RNC

There are 3 events for the soft handover.

The value measured is the CPICH Ec/No.

The event 1a is triggered when the CPICH Ec/No of a monitored cells is above a

certain threshold.

If the event is fulfilled the cell is added in

the active set

The event 1b is triggered when the CPICH

Ec/No of a active cell is below a certain threshold.

If the event is fulfilled the cell is removed

from the active set

The event 1c is triggered when the active set has reached its maximum size and the

CPICH Ec/No of a monitored cells is better

than a cell belonging to the active set.

If the event is fulfilled the candidate cell

replaces the cell in the active setCell in the Active Set

Cell in the Monitoring Set

The simplified formula to trigger an 1a event is :

� 10log(Mnew) > 10log (MBest) – R1a

Where:

� Mnew is a measurement on the candidate cell about the quality of reception.

� Mbest is a measurement on the best cell in the active set about the quality of reception.

� R1a is the “Reporting Range”.

Best

Cell

T1 -> Event 1a

R1a

CPICH

Ec/N0

Time

Candidate

Cell

T0






3 � 53


5.3 Compressed Mode

Iub

RNC


Cell in the Monitored Set, same FDD frequency

Cell in the Monitored Set, other FDD frequency

Cell in the Monitored Set, GSM cell

Most of the UEs are not dual receivers.

And they need to perform measurements

on other frequencies.

So UTRAN has to free it time window to

perform these measurements on other

FDD frequencies or on GSM frequencies.

The main method is to divide the SF of certain frame by 2, so it divides the length of the frame by 2.

Time interval to measure other frequencies

Compressed mode method available according to the 3GPP TS 25.212

� compressed mode methods:

� By puncturing : the rate matching is applied for creating a transmission gap in one or two

frames (not in UL)

� Reducing the SF by 2

� Compressed frames can be obtained by higher layer scheduling. Higher layers then set

restrictions so that only a subset of the allowed TFCs are used in a compressed frame. The

maximum number of bits that will be delivered to the physical layer during the compressed

radio frame is then known and a transmission gap can be generated






3 � 54


5.4 Hard HO: Events on other FDD Frequencies

Iub

RNC





There are 4 events to watch the UMTS cell

with other FDD frequencies

The event 2d_cm is triggered when the quality of on the current frequency is

below a certain quality. The compressed

mode is launched.

The event 2b is triggered when the quality of the current frequency is belowa certain threshold and the quality on an

other frequency is above a certain

threshold

The event 2f is triggered when the quality on the current frequency is above a

certain threshold. The compressed mode

is deactivated.






3 � 55


5.5 Hard HO: Events on other GSM Frequencies

Iub

RNC





2 causes can trigger an hard HO toward the

GSM system:

• Some bad radio conditions

• due to the service requested

The event 2d_cm is triggered when the quality of on the current frequency is below

a certain quality. The compressed mode is

launched.

The event 3a is triggered when the quality on the current FDD frequency is below a

certain threshold and the quality on the GSM

is above another threshold.

The event 3c is triggered when the service requested can be managed by the GSM, the

voice typically.






3 � 56

6 Exercises






3 � 57

6 Exercises

6.1 Scenario Description

Objectives:Rebuilt the channels mapping, Logical, Transport and Physical channelsfrom a scenario to guide you with the 2 next pages

Scenario:

• The UE switches on in a covered area

• The UE collects information about the system

• The UE requests a RRC connection to declare its location and releases the RRC connection

• The UE receives a paging message to receive an e-mail

• UTRAN establishes a RAB and is in the DCH_Cell State

• As the traffic is not large, the UE passes to the FACH_Cell State

Be careful, following this scenario, some channels are missing.Which are the missing channels ?






3 � 58

6 Exercises

6.2 Downlink

Logical Ch.

Transport Ch.

Physical Ch.






3 � 59

6 Exercises

6.3 Uplink

Logical Ch.

Transport Ch.

Physical Ch.






3 � 60

Evaluation


Objective: To be able to build the map of the radio channels (logical, transport and physical channels) from a white paper.






3 � 61

End of Module

Page 1

All Rights Reserved © Alcatel-Lucent @@YEAR3JK10658AAAAWBZZA Edition 1




Edition 1

Glossary

Page 2



UA06 R99 Radio Principles

2

Blank Page


First editionNBX2006-10-0901


Document History

Page 3




3

Abbreviations and Acronyms

� Switch to notes view!# 16-QAM 16 – Quadrature Amplitude Modulation 3GPP 3rd Generation Partnership Project A AAL ATM Adaptation Layer ACELP Algebraic Code Excited Linear Prediction ACK Acknoledgement ADN Abbreviated Dialling Number AID Alarm Instance Identification ALCAP Access Link Control Application Part AMPS Advanced Mobile Phone System AMR Adaptive Multi Rate ANRU Antenna Network and multi-carrier Receiver UMTS ANSI American National Standard Institute

(USA) ARIB Association of Radio Industries and Business (Japan) ATC ATM Traffic Contract ATM Asynchronous Transfer Mode B BB Base Band BCCH Broadcast Control Channel BER Bit Error Rate BHCA Busy Hour Call Attempts BLER Block Error Rate BMC Broadcast Multicast Control BM-IWF Broadcast Multicast Inter-Working Function BPMT Node B Performance Monitoring Tool BSC Base Station Controller BSS Base Station (sub)System BTS Base Transceiver Station BWC Bandwidth Control C CAC Connection Admission Control CAMEL Customised Application for Mobile CAPEX CAPital EXpenditure Enhanced Logic CC Call Control CCCH Common Control Channel CCO Cell Change Order CCT Call Context Template CCTrCH Coded Composite Transport Channel CDMA Code Division Multiple Access CDR Call Data Record CDV Cell Delay Variation CLR Cell Loss Ratio CM Configuration Management CN Core Network CONT Controller CPCH Common Packet Channel CPCS Common Part Convergence Sub-layer

CPS Command Part Sub-layer CPU Central Processing Unit CQI Channel Quality indicator CRC Cyclic Redundant Check CS Circuit Switched CS Convergence/Adaptation to Services

(ATM) CTCH Common Traffic Channel CTD Cell Transfer Delay

D DB Debug DCA Dynamic Channel Allocation DCCH Dedicated Control Channel DCH Dedicated Channel DCN Data Communication Network DHO Diversity HandOver DHT Diversity HandOver Trunk DL Downlink DPCH Dedicated Physical Channel DPCCH Dedicated Physical Control Channel DPDCH Dedicated Physical Data Channel DRAC Dynamic Resource Allocation Control DRNC Drift RNC DS Direct Sequence DSCH Downlink Shared CHannel DTCH Dedicated Traffic Channel E E-DCH Enhanced Dedicated CHannel EDGE Enhanced Data rates for GSM Evolution EFR Enhanced Full Rate E-GSM Enhanced GSM E-GPRS Enhanced GPRS EM Element (or Equipment) Manager ERAN EDGE Radio Access Network (all-IP) ETSI European Telecommunication Standard

Institute F FACH Forward Access Channel FAD Function Access Domain FBI Feed-Back Information FDD Frequency Division Duplex FDL File Download (EM application) FDMA Frequency Division Multiple Access FER Frame Error Rate FTP File Transfer Protocol FW Firmware

Page 4




4

Abbreviations and Acronyms [cont.]

� Switch to notes view!G GCRA Generic Cell Rate Algorithm GERAN GSM/EDGE Radio Access Network GGSN Gateway GPRS Support Node GMSC Gateway MSC GMSK Gaussian Minimum Shift Keying GP Granularity Period GPRS General Packet Radio Service GSM Global System for Mobile

Communications GTP GPRS Tunneling Protocol GTP-U GPRS Tunneling Protocol-User Plane GUI Graphical User Interface H HCS Hierarchical Cell Structure HHO Hard HandOver HIF High speed Interface HLR Home Location Register HO HandOver HSDPA High Speed Downlink Packet Access HS-DPCCH High Speed Dedicated Physical Control

CHannel. HS-DSCH High Speed Downlink Shared CHannel HSS Home Subscriber Service HS-SCCH High Speed Shared Control CHannel HSUPA High Speed Uplink Packet Access HPLMN Home PLMN I IMEI International Mobile Equipment Identity IMS IP Multimedia Subsystem IMSI International Mobile Subscriber Identity IMT International Mobile Telecommunication IMT-DS Direct Sequence IMT-MC Multi Carrier IMT-SC Single Carrier IMT-TC Time Code IOT Inter Operability Tests IOR Interoperable Object Reference IP Internet Protocol IR Incremental Redundancy ISC Internetworking Services Card ISDN Integrated Services Digital Network Itf-b Interface Node B - OMC-R Itf-r Interface RNC - OMC-R ITU International Telecommunication Union Iub Interface Node B - RNC Iur Interface RNC - RNC Iu-CS Interface RNC - CN Circuit Switch Iu-PS Interface RNC - CN Packet Switch K Kbps Kilo Bit per Second

L L1, L2, L3 Layer , Layer 2, Layer3 LA Local Area LAC Local Area Code LAN Local Area Network LCS LoCation Services LED Light Emitting Diode LLC Logical Link Control LoS Line of Sight LM Load Module LMT Local Maintenance Terminal LIF Low speed Interface LQC Link Quality Control M MAC Medium Access Control MAC-hs Medium Access Control - High Speed MAP Mobile Application Part MBS Multi-standard Base Station (UTRAN) MBS Maximum Burst Size (ATM) MCR Minimum Cell Rate MIMO Multiple Input / Multiple Output MM Mobility Management MMUX MAC Multiplexer MSC Mobile Switching Centre MSP Multiple Subscriber Profile MTP3 Message Transfer Part level 3 MTP-3B Message Transfer Part level 3 Broadband N NACK Non-Acknoledgement NAS Non Access Stratum NAD Network Access Domain NBAP Node-B Application Part NE Network Element N/E Normal/ Emergency NEM New element manager NEM-B Network Element Manager for Node B NEM-R Network Element Manager for RNC NM Combined EM and SNM NML Network Management Layer NMS Network Management System NPA Network Performance Analyser NTP Network Time Protocol

Page 5




5


� Switch to notes view!O OAM Operation And Maintenance O&M Operation And Maintenance OD Office Data ODMA Orthogonal Division Multiple Access ODT Office Data Tool ODTM Office Data Tool Macro OFDM Orthogonal Frequency Division

Multiplexing OMC-R Operation & Maintenance Centre - Radio OPEX OPerational EXpenditures ORB Object Request Broker OS Operating System OSA Open Service Architecture OTDOA Observed Time Difference of Arrival OTSR Omni directional Tx / Sectorised Rx OVSF Orthogonal Variable Spreading Factor P PCCH Paging Control Channel PCR Peak Cell Rate PCU Packet Control Unit PDA Personal Digital Assistant PDC Personal Digital Cellular (2G Japan) PDP Packet Data Protocol PDU Protocol Data Unit PFS Proportional Fair Scheduling PLMN Public Land Mobile Network PM Performance Measurement (O&M) PRACH Physical Random Access Channel PS Packet Switched PSK Phase Shift Keying PSTN Public Switched Telephone Network Q QoS Quality of Service QPSK Quadrature Phase Shift Keying R R5 Release 5 R’99 Release ’99 RA Routing Area RAB Radio Access Bearer RAC Routing Area Code RAC Radio Admission control RACH Random Access Channel RAID Redundant Array Independent (or Inexpensive) Disk RAN Radio Access Network RANAP RAN Application Part RB Radio Bearer RR Round Robin RF Radio Frequency RLC Radio Link Control RNC Radio Network Controller

RNO Radio Network Optimiser RNS Radio Network Sub-System RNSAP RNS Application Part RNTI Radio Network Temporary Identity RP Reporting Period RPMT RNC Performance Monitoring Tool RRC Radio Resource Control RRM Radio Resource Management RV Redundancy Version S SAC Service Area Code SAP Service Access Point SAR Segmentation And Re-assembly SAT SIM Application Toolkit SC Short Cell SC System Configuration SCF System Configuration File SCR Sustainable Cell Rate SDH Synchronous Digital Hierarchy SF Spreading Factor SGSN Serving GPRS Support Node SHO Soft HandOver SIR Signal to Interference Ratio SL Scheduling List SMS Short Message Service SNMP Simple Network Management Protocol SPU Signaling Processing Unit SQL Structured Query Language SRNC Serving RNC SSCOP Service Specific Connection Oriented

Protocol SSCP Signaling Connection Control Part STM Synchronous Transfer Mode STTD Space Time transmit diversity SU Signalling Unit

Page 6




6


� Switch to notes view!T TC Transcoder TC Transmission Convergence (ATM) TCP Transport Control Protocol TD-CDMA Time Division & CDMA TDD Time Division Duplex TDMA Time Division Multiple Access TEU Transmitter Equipment UMTS TF Transport Format TFC Transport Format Combination TFCI Transport Format Combination Indicator TFCS Transport Format Combination Set TFRC Transport Format Resource Combination TFRI Transport Format Resource Indicator TFS Transport Format Set TIA Telecommunication Industry Association

(USA) TMA Tower Mounted Amplifier TMN Telecommunication Management

Network TMSI Temporary Mobile Subscriber Identify TPA Transmit Power Amplifier TPC Transmission Power Control TQL Query Language for semi-structured data TRE Transceiver Equipment (GSM) TRX Transceiver (UMTS V1) TS Tunning Session TSAL Tunning Session Application Log TSTD Time Switch Transmit Diversity TTA Telecommunication Technology

Association (Korea) TTI Transmission Time Interval U UARFCN UTRA Absolute Radio Frequency Channel Number UDP User Datagram Protocol UE User Equipment UICC UMTS Integrated Circuit Card UL Uplink UMTS Universal Mobile Telecommunication System URA UTRAN Registration Area USB Universal Serial Bus USIM UMTS Subscriber Identity Card USM User Service Manager USSD Unstructured Supplementary Service Data UTRA UMTS Radio Access Network (ETSI) UTRA Universal Radio Access Network (3GPP) UTRAN UMTS Terrestrial Radio Access Network UWCC Universal Wireless Communications

Committee

V VC Virtual Channel VCI Virtual Channel Identifier VHE Virtual Home Environment VLR Visitor Location Register VoIP Voice over IP VP Virtual Path VPI Virtual Path Identifier VSWR Voltage Standing Wave Ratio W W3C World Wide Web Consortium WAP Wireless Application Protocol W-CDMA Wide-band Code Division Multiple

Access WIM WAP Identity Module X XML Extensible Mark-up Language

@@COURSENAME - Page 1All Rights Reserved © Alcatel-Lucent @@YEAR


@@COURSENAME@@PRODUCT

1

Last But One Page



@@COURSENAME - Page 2All Rights Reserved © Alcatel-Lucent @@YEAR

All rights reserved © Alcatel-Lucent @@YEARPassing on and copying of this document, use and communication of its

contents not permitted without written authorization from Alcatel-Lucent

WCDMA Radio Principles

Documents