umts network systems overview day1

8/13/2019 UMTS Network Systems Overview Day1

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1U101 UMTS Network Systems Overview

UMTS Network Systems

Overview

Day 1


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Introductory Session



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Introductions



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Introduction to AIRCOM

Contents and Session Aims

This session is a get to know

you session It aims to answer the following

questions:

Who are AIRCOM and why arethey here training us?

Should I be here?

Why am I here?

It also aims to cover thelogistics of the course

Whens the

lunch/coffee/cigarette break?

What are we going to learnabout and when?

Target Students

Course Prerequisites

Aims of the Course

Course Schedule and

Organisation


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Target Students

This course is aimed at: Engineers and technical specialists familiar with

telecommunications and looking for an introduction to UMTS

Technically orientated managers looking to understand thetechnology behind UMTS



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Prerequisites

An understanding of the basic concepts of: Telecommunications

Cellular communications

Wireless communications



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8/2248U101 UMTS Network Systems Overview

Course ScheduleDay 1 Day 2

9:30-

10:15

Introductory Session1st/2ndGeneration

Cellular SystemsOverview

UTRAN

Drinks Break Drinks Break

10:45-11:30

3rdGeneration Driversand Standards

UTRAN (cont.)


12:00-12:45

CDMA MobileTechnology Overview

UMTS Core Network

Lunch Lunch

13:45-14:30

UMTS ArchitectureOverview

UMTS Fixed NetworkInterfaces


15:00-15:45

UTRA Air Interface UMTS Mobiles


16:15-17:00

UTRA Air Interface(cont.) UMTS Services

17:00-17:30

Day 1 Roundup Course Roundup




How the Sessions are Organised

Locator Slide To remind you where you are when you wake up!

Theres also a section title at the top left of the slide...

Contents and Aims

New Material for the Session Questions (please ask anytime!) Questions to You (to make sure youve been listening and

understand)

Questions to Me (if you dont understand or want to know more)

Section Summary




Locator Slide

In t roduc tory Session

1st and 2nd Generation CellularSystems Overview

3rd Generation Drivers andStandards

CDMA Mobile TechnologyOverview

UMTS Architecture Overview

UTRA Air Interface

Day 1 Roundup

Day 2 Introductory Session

UTRAN

UMTS Core Network

UMTS Fixed Network Interfaces

UMTS Mobiles

UMTS Services

Course Roundup




Questions

Any questions?




Locator Slide


1st and 2nd Generat ionCel lu lar Systems Overview




UTRA Air Interface

Day 1 Roundup


UTRAN

UMTS Core Network


UMTS Mobiles

UMTS Services

Course Roundup

1st and 2nd Generation Cellular Systems Overview




1st and 2nd Generation Cellular

Systems Overview

G C S O





This is a background session to

set the scene for UMTS,essentially a cellular historylesson

Firstly we will examine what wemean by cellular

communications We will look at different

generations of cellular andbriefly at major standards

This will allow us to see why 3G

has moved forward in the waythat it has

What is Cellular?

Cellular Generations1st Generation

2nd Generation

2.5G

1 t d 2 d G ti C ll l S t O i



What is Cellular? There are three major types of

terrestrial mobile communications

technologies Cellular

Users are provided wide areamobility from multiple basestations with handover permitted

Cordless Communication Users are provided limited

mobility from a dedicated basestation

Paging

Brief numeric, alphanumeric orvoice messages are sent to thesubscriber typically usingsimulcasting


PSTNMSC

Paging

Control

Centre

Cellular

Cordless

Paging


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1st Generation

1976+, though really the

technology of the 1980s Analogue modulation

Frequency Division MultipleAccess

Voice traffic only

No inter-network roamingpossible

Insecure air interface


The 1st Generation of

Cellular Technology makesuse of analog modulation

techniques such as FM




1st Generation Standards

AMPS (Analogue Mobile Telephony System) North American Standard in cellular band (800MHz)

TACS (Total Access Communications System) UK originated Standard based on AMPS in 900MHz band

NMT (Nordic Mobile Telephony System) Scandinavian Standard in 450MHz and 900MHz bands

C-450 German Standard in 450MHz band

JTACS (Japanese Total Access Communications System) Japanese Standard in 900MHz band





1st Generation Planning

Macrocellular High sites for coverage driven

planning

Antennas above roof height

Frequency planning required

Large cell size Order 30km

Hard handover Only ever connected to a single

cell


Cellular Networks are

commonly represented as

hexagon grids.

The above diagram shows how

different frequencies are used

in different cells in a cellular

network (different frequencies

represented by different

colours).For networks with more cells

than frequencies these must be

planned




2nd Generation

1990s

Digital modulation

Variety of Multiple Accessstrategies

Voice and low rate circuitswitched data

Same technology roaming

Secure air interface


The 2nd Generation of

Cellular Technology is the

first to use digitalmodulation





GSM

First networks in 1992

European developed standard,but with worldwide subscriberbase

Different frequency bands GSM450, GSM900, GSM1800,

GSM1900 Largest 2nd Generation

subscriber base

Frequency/Time DivisionMultiple Access

Open/Standardised Interfaces

GSM phones from

1999/2000



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GSM Planning Macrocells and microcells

Capacity driven planning

Frequency planning required Optional parameters requiring

planning

Hierarchical Cell Structures

Frequency Hopping

Discontinuous Transmission

Power Control

Simple subscriber/trafficanalysis

Capacity limited by number ofTRXs

Hard Handover


GSM networks usemicrocells to provide

additional capacity. As with

1st generation networks

frequency planning is

required



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D-AMPS/PDC

TDMA (D-AMPS) North American TDMA/FDMA

based standard based uponAMPS

Predominantly used in Northand South America

ANSI-41 Core Network Planning Similar to GSM

PDC Japanese TDMA/FDMA based

standard

Predominantly used in Asia

Planning Similar to GSM


TDMA and PDC phones

from 1999/2000



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cdmaOne

First networks in 1996

Derived from Qualcomm IS-95air interface

Largely American subscriberbase with some Asian networks

Code Division Multiple Access This is in many ways the

closest 2nd generation standardto many of the 3rd generationstandards

ANSI-41 core network

Chip rate of 1.2288Mcps


cdmaOne phones from

1999/2000



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cdmaOne Planning

Macrocells and microcells

Single Frequency multiple frequencies for

hotspots

Soft Handover (multipleconnections between mobile

and network)

Code Planning

Capacity Interference Limited 1 Connection

2 Connections

3 Connections


Unlike GSM there is no

frequency planning

required for cdmaOne

However soft handover

means that there are

zones where there are

two/three connections

to the network



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Worldwide Mobile Communications inthe 1990s

0

100200

300

400

500

600

700

1991

1993

1995

1997

1999

2001

Second Generation -D-AMPS

Second Generation -PDC

Second Generation -GSM

Second Generation -cdmaOne

First Generation -Analogue

MillionSubscribers

Year Source:Wideband CDMA for 3rdGeneration Mobile Communications,

Artech House, 1998




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Worldwide Mobile Subscribers

0

500

1000

1500

2000

1995 2000 2005 2010

European UnionCountries

North America

Asia Pacific

Rest of World

MillionSubscribers

Year Source:Third Generation MobileCommunications, Artech House, 2000




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2.5G

Now...

Digital modulation Voice and intermediate rate

circuit/packet switched data

Same technology roaming

Secure air interface Based upon existing dominant

standards such as GSM orcdmaOne


2.5G technologies arebased upon existing 2G

technologies but are

focussed at increasing

the maximum data

rates that the

technologies can

deliver



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HSCSD

High Speed Circuit Switched

Data Enhancement to the GSM

standard

Utilises: Multiple channel coding

schemes (4.8kbps, 9.6kbps,14.4kbps per timeslot)

Multiple timeslots

Circuit Switched Data rates to57.6kbps (4 slots with 14.4kbps

channel coding per slot) Nokia Cardphone




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GPRS

General Packet Radio Service

Enhancement to the GSMstandard

Utlilises Multiple Channel Coding

Schemes (9.05kbps, 13.4kbps,

15.6kbps, 21.4kbps) Multiple Timeslots

Packet Switching

Packet Switched Data typicallyto rates of 115kbps

Theoretically 171.2kbps for 8timeslots

Ericsson R520

(available 1Q 2001)Sagem MC850

Alcatel One Touch 700

(available October

2000)



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2G and 2.5G Standards Compared

GSM TDMA cdmaOne PDC

MultipleAccess TDMA TDMA CDMA TDMA

Modulation GMSK /4-DQPSK QPSK /4-DQPSK

CarrierSpacing

200kHz 30kHz 1.25MHz 25kHz

Frame Length 4.615ms 40ms 20ms 20ms

Slots per

Frame

8 6 1 3/6

FrequencyBand

450/ 900/ 1800/1900

800/ 1900 800/ 1900 850/ 1500

Max DataRate

HSCSD:115kbps

GPRS: 115

172kbps

IS-136+:43.2kbps

IS-95A:14.4kbpsIS-95B:

115.2kbps

28.8kbps

FrequencyHopping

Yes No N/A No

Handover Hard Hard Soft Hard

y



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Questions

What defines a 1st generation technology and a 2ndgeneration technology?

What is are the main differences between GSM andcdmaOne?

How do 2.5G standards relate to 2G standards?

y



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Session Summary

Weve now set the scene - we can start talking aboutwhere people want to go from here now

The generations of cellular technology may besummarised:

1G is analog voice

2G is digital voice

2.5G is digital intermediate rate data

You also know its the coffee break nowand to comeback at 10:45!

y

3rd Generation Drivers and Standards


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Locator Slide



3rd Generat ion Drivers andStandards


UTRA Architecture Overview

UMTS Air Interface

Day 1 Roundup


UTRAN UMTS Core Network


UMTS Mobiles

UMTS Services Course Roundup



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Introduction and Session Aims

This session is focussed atlooking at how and why the 3rd

Generation standards haveevolved

Firstly we will look at the goalsand the focus of the ITU in IMT-2000

We will then examine whatdrivers from the regions and thevarious industry bodies whohave an interest in 3rdGeneration

Finally we will round up bylooking at the IMT-2000 cellularstandards

IMT-2000

IMT-2000 spectrum

Drivers from Europe,

America and Asia

Regulatory bodiesStandardisation bodies

Industry associations

3rd Generation CellularStandards



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IMT-2000

IMT-2000 (International Mobile Telecommunications 2000)is a program focussed at providing a single globalstandard for mobile communications

Development started in 1985 as FPLMTS Future Public Land Mobile Telecommunications System

Proposed by the ITU (International TelecommunicationsUnion)



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Who does IMT-2000 serve?

Integrating all the following users

fixed

cellular

cordless

professional mobile radiopaging

satellite

specialised (aeroplane, etc)IMT-2000

terminal and

services



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Aspects of IMT-2000 Networks

Different aspects

of IMT-2000

access networks



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What are the IMT-2000 goals?

Data Rates Local area - 2 Mbps

In office, stationary

Limited mobility - 384 kbps

Urban pedestrian

Full mobility - 144 kbps Rural in car

High spectrum efficiency compared to existing systems

High flexibility to introduce new services



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IMT-2000 Spectrum

1800 20501900 1950 20001850 2100 2150 2200

ITU

(WARC-92)

Europe

Japan

Korea

USA

1885 1980 2010 2025 2110 2170 2200

1920 1980 2010 2025 2110 2170 2200

1920 1980 2110 2170

2110 21701920 1980

1850 1910 1930 1990 2110 2200

MSS MSS

IMT-2000

Land Mobile

IMT-2000

Land Mobile UL

IMT-2000

Land Mobile UL

IMT-2000

Land Mobile

IMT-2000

Land Mobile DL

IMT-2000

Land Mobile DL

UMTS

Paired UL

UMTS

Paired DL

UMTS

SAT

UMTS

SAT

UMTS

Unpaired

UMTS

Unpaired

IMT-2000

Land Mobile

PCS

UL

PCS

DLReserved

1900

DECTGSM 1800

1880



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IMT-2000 Future Spectrum

ITU

(WRC-2000)

Europe

Japan

Korea

USA

2200 3000600 1000 1400 1800 2400

806 960 1710

1880

2500 2690

890 960 1710

GSM 1800GSM 900

New IMT-2000 New IMT-2000 New IMT-2000

Cellular PCS

IMT 2000 C did t T h l3rd Generation Drivers and Standards


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IMT-2000 Candidate TechnologyEvaluation

The ITU issued a request for proposals for the Radio

Transmission Technology (RTT) for IMT-2000 to besubmitted in June 1998

Following this a self evaluation of the RTT submitted wasrequired by September 1998

Candidate technologies were then evaluated according totheir compliance with the goals for IMT-2000



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IMT-2000 Candidate Harmonisation

A number of technologies were submitted many of which

had distinct similarities Of course operators were generally keen on a single

standard to allow global roaming and economies of scale

Operators Harmonisation Group (OHG)

This led to two partnership projects being set up: 3rd Generation Partnership Project (3GPP)

Dealing with UMTS FDD/TDD and related candidate technologies a

3rd Generation Partnership Project 2 (3GPP2)

Dealing with cdma2000 and related candidate technologies



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3G Standardization Environment

Key Players and

their relationships

in the IMT-2000standardisation

environment

IMT 2000

S l t d Ai I t f3rd Generation Drivers and Standards


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Five candidate technologies

were eventually selected: IMT-DS (Direct Spread)

UMTS FDD

IMT-MC (Multi Carrier)

cdma2000

IMT-TC (Time Code)UMTS TDD

IMT-SC (Single Carrier)

EDGE/UWC-136

IMT-FT (Frequency Time)

DECT

IMT-2000 Selected Air InterfaceStandards


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IMT-2000 Standards

The IMT-2000family of

standards



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North America and US influenced countries Dominated by 2G TDMA/cdmaOne

USA has slower growth because recipient party pays

Mess of digital systems at 800 and 1900 MHz

US manufacturers have pushed forward growing cdmaOnestandard

PCS spectrum overlaps IMT-2000 band

Major Drivers

Spectrum sharing and compatibility with 2G standard

National/International roaming

cdma2000 (cdmaOne operators)

EDGE (TDMA operators)

North America Drivers



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Europe and European Influenced Countries GSM provided 2nd generation roaming across Europe Plenty of Capacity at 1800MHz

IMT2000 band compatible with current spectrum usage leads to nospectrum sharing issues

EU enforced standardisation means UMTS for at least 1 operatorper country

Major Drivers

Higher Data Rates

Continued global dominance of European based standard

UMTS

European Drivers



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Japan/Korean Drivers

Japan and Korea PHS and PDC left Japanese manufacturers isolated

IMT2000 band compatible with current spectrum usage leads to nospectrum sharing issues

Political US relationships...

Major Drivers Capacity for Voice

Global market for cellular infrastructure

UMTS



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Cordless Drivers

You cant get 2Mbps out of the cellular standards

Hence a requirement for cordless style standards UMTS TDD Mode

DECT



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Industry Bodies - Radio Regulatory

ITU (International)

http://www.itu.int/

ERO (EU) European Radio Office

http://www.ero.dk/

RA (UK) Radiocommunications Agency

http://www.radio.gov.uk/

FCC (USA) Federal Communications

Commission

http://www.fcc.gov/

I d B di T d A i i



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Industry Bodies - Trade Associations

UMTS Forum

http://www.umts-forum.org/

GSM Association http://www.gsmworld.com/index1.html

CDMA Development Group

http://www.cdg.org/ GSM Suppliers Association

http://www.gsacom.com/home.html

Universal Wireless CommunicationsConsortium

http://www.uwcc.org/


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P t hi P j t d St d d3rd Generation Drivers and Standards


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Partnership Projects and StandardsOrganisations

Relationships

between thestandards

organisations

3GPP M b O i ti



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3GPP Member Organisations

ETSI (EU) http://www.etsi.org/

ARIB (Japan) http://www.arib.or.jp/arib/english/

T1 (USA) http://www.t1.org/

TTC (Japan) http://www.ttc.or.jp/e/

TTA (Korea) http://www.tta.or.kr/

CWTS (China) http://www.cwts.org/cwts/index_eng.html

3GPP2 M b O i ti



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3GPP2 Member Organisations

TIA (USA)

http://www.tiaonline.org/

TTA (Korea) http://www.tta.or.kr/

TTC (Japan)

http://www.ttc.or.jp/e/ ARIB (Japan)

http://www.arib.or.jp/arib/english/

CWTS (China) http://www.cwts.org/cwts/index_eng.html

Th R d t 3G3rd Generation Drivers and Standards


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The Road to 3G

PossibleEvolution Paths

to 3G

HSCSD

3 d G ti C ll l3rd Generation Drivers and Standards


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3rd Generation Cellular

2002+

Digital modulation Voice and high rate data

Multi technology roaming

Secure air interface

Standards UMTS FDD (CDMA based)

UMTS TDD (CDMA based)

cdma2000 (CDMA based)

EDGE (TDMA based)

UMTS FDD3rd Generation Drivers and Standards


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UMTS FDD

Universal Mobile Telecommunications System FrequencyDivision Duplexing Mode

Built onto enhanced GSM core network

Utilises: QPSK modulation

Multiple channel coding and bearer rates Variable spreading factors and multi-code transmission

CDMA

FDD

Asynchronous operation Data up to rates of 2Mbps (typically less)

UMTS C d t GSM3rd Generation Drivers and Standards


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UMTS Compared to GSMUMTS GSM

Carrier Spacing 5MHz 200kHz

Frequency ReuseFactor

1 1-18

Power ControlFrequency

1500Hz 2Hz or lower

Quality Control Radio ResourceManagement

algorithms

Frequency Planningand Network

OptimisationFrequency Diversity 5MHz bandwidth gives

multipath diversity withrake reciever

Frequency Hopping

Packet Data Load Based PacketScheduling

Time Slot basedScheduling with GPRS

Transmit Diversity Supported to improvedownlink capacity Not supported bystandard but may beapplied

UMTS Compared to IS953rd Generation Drivers and Standards


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UMTS Compared to IS95UMTS IS-95

Carrier Spacing 5MHz 1.25MHz

Chip Rate 3.84Mcps 1.2288McpsPower ControlFrequency

1500Hz Uplink 800Hz,Downlink slow

Base StationSynchronisation

No Yes via GPS

Frequency Inter

FrequencyHandovers

Yes, slotted mode

measurements

Possible but

measurements notspecified

Packet Data Load Based PacketScheduling

Packets as short CScalls

Radio ResourceManagement

Efficient algorithms toprovide QoS

Not required forspeech only

Transmit Diversity Supported to improvedownlink capacity

Not supported bystandard

UMTS TDD3rd Generation Drivers and Standards


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UMTS TDD

Universal Mobile Telecommunications System Frequency

Division Duplexing Mode Built onto enhanced GSM core network


Multiple channel coding and bearer rates

CDMA

TDD

Asynchronous operation

Data up to rates of 2Mbps (typically less)

cdma20003rd Generation Drivers and Standards


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cdma2000

Built onto ANSI-41 core network


Multiple channel coding and bearer rates

CDMA

FDD

Multiple carriers on the downlink to allow compatibility withcdmaOne

Synchronous operation

Data up to rates of 2Mbps (typically less)

EDGE3rd Generation Drivers and Standards


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EDGE

Enhanced Data for GSM Evolution Sometimes called E-GPRS (Enhanced GPRS)

Enhancement to the GSM and TDMA standards

Utlilises: 8PSK Modulation

Possible 1.6MHz carrier under IS-136

8 Channel Coding Schemes

Multiple Timeslots

TDMA

Data up to rates of 384kbps (typically less)

3rd Generation Standards Compared3rd Generation Drivers and Standards


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3rd Generation Standards ComparedUMTS FDD UMTS TDD cdma2000 EDGE

Multiple

Access

CDMA CDMA CDMA TDMA

Modulation QPSK QPSK QPSK 8-PSK

CarrierSpacing

5MHz (200kHzraster)

5MHz (200kHzraster)

3.75MHzUL/1.25MHz DL

200kHz/1.6MHz

Frame Length 10ms 10ms 20ms 4.615ms

Slots per

Frame

15 15 16 8/16/64

MultipleRates

Multi-code,Variable

Spreading Factor

Multi-code, multi-slot

SupplementalChannels, Multiplespreading Factors

Multiple channelcode, multi-slot

Chip Rate 3.84Mcps 3.84Mcps 3.6868Mcps

Max Data

Rate

2Mbps 2Mbps 2Mbps 521/4750kbps

Synchronous No No Yes Yes

Handover Soft Hard Soft Hard

4th Generation3rd Generation Drivers and Standards


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4th Generation...

Probably 2005-2007

Broadband data rates in excessof 1Mbps

Probably 10MHz+ carriers

...

Questions3rd Generation Drivers and Standards


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Questions

What is IMT-2000 and why is it related to UMTS?

Why do the American operators want cdma2000 andEDGE?

What is the major difference between UMTS andcdma2000?

Session Summary3rd Generation Drivers and Standards


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Session Summary

In this session we have discussed: The key goals of IMT-2000

The drivers for 3rd generation from the regions

The key industry bodies and their relationships

The four cellular air interfaces for IMT-2000 are:

UMTS FDD UMTS TDD

cdma2000

EDGE

Locator SlideCDMA Mobile Technology Overview


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Locator Slide




CDMA Mobi le Technolo gyOverview


UMTS Air Interface

Day 1 Roundup


UTRAN UMTS Core Network


UMTS Mobiles

UMTS Services Course Roundup

CDMA Mobile Technology Overview


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Contents and Session AimsCDMA Mobile Technology Overview


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This session aims to coversome basic CDMA terminologyand technology before dealingwith UMTS in more detail

Key generic areas of CDMAinclude

How CDMA works and relatesto other multiple accessschemes

How the codes are generatedand what their properties are

Soft Handover - what and how?

The pilot channel

Multiple Access

Strategies ExplainedCDMA for Cellular

Codes in CDMA

Soft Handover

The Pilot Channel

Multiple Access ExplainedCDMA Mobile Technology Overview


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Multiple Access Explained

Imagine you are in a cocktail party

Now imagine you are trying to talk to somebody (rather than fighting your way to the punch bowl again...)

If you are trying to listen to somebody you need to be ableto pick out their speech from everybody elses speech.

Everybody is using the same medium to talk - the air inthe room

Clich ExplanationCDMA Mobile Technology Overview


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Clich Explanation

This is Multiple Access Many conversations/channels share the same medium

There are a number of different Multiple Access (MA)strategies you can try:

Time Division Multiple Access(TDMA)

Frequency Division Multiple Access(FDMA)

Code Division Multiple Access(CDMA)

TDMA at the Cocktail PartyCDMA Mobile Technology Overview


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TDMA at the Cocktail Party

We divide time into a number of timeslots

Everybody takes turns to speak within a timeslot Once everybody has spoken we go back to the start of the list andbegin again - this is a frame

This ensures that two conversations/channels dont get confused.

Conversation/Channel separation is provided in time.

Bit of problem if people speak late or early We may need guard periodsbetween timeslots when nobody speaks

People need to know when to speak We need signaling to tell people their timeslot

TDMACDMA Mobile Technology Overview


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TDMA

frequency

time

User 1 User 1

Timeslot Period Frame Period

Idealised TDMA

(with no guard

periods)

Available

Frequency

Band

FDMA at the cocktail partyCDMA Mobile Technology Overview


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FDMA at the cocktail party

We divide the available frequency band into a number of frequencychannels of the same channel bandwidth

People speak continuouslyat different frequencies/pitches, and useearpieces to filter out frequencies theyre not interested in.

Again this ensures that two conversations dont get confused.

Conversation/Channel separation provided in frequency.

Bit of a problem as the filters arent perfect We may need guard bandsbetween timeslots when nobody speaks

People need to know the frequency of the conversation We need signaling to tell people their frequency channel

FDMACDMA Mobile Technology Overview


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FDMA

frequency

time

User 1

Frame Period (we may still need

frames/timeslots for signaling)

Channel

Bandwidth

Idealised FDMA

(with no guard

bands)

FDMA/TDMACDMA Mobile Technology Overview


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FDMA/TDMA

Of course we could also be clever and use a combination

of TDMA and FDMAlike in GSM This is commonly referred to as simply TDMA

FDMA/TDMACDMA Mobile Technology Overview


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FDMA/TDMA

frequency

time

Channel

Bandwidth


User 1 User 1Idealised

FDMA/TDMA

(with no guardbands or guard

periods)

FH at the Cocktail PartyCDMA Mobile Technology Overview


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FH at the Cocktail Party

If we combine TDMA and FDMA and change the frequency oftransmission every frame we have Frequency Hopping

Frequency hopping improves the received quality of theconversation/channel

We can tolerate the occasional collision of words:

The next word is almost certain to get through

We can always repeat the odd word This generally wont have too great an impact on the meaning of the

conversation.

This is sometimes called frequency hopping spread spectrum This is because the total bandwidth used for an individual conversation is

greater than that strictly required for the individual conversation i.e. the spectrum has been spread

Frequency Hopping Spread SpectrumCDMA Mobile Technology Overview


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Frequency Hopping Spread Spectrum

f

requency

timeUser 1 User 1

Channel

Bandwidth


Idealised FH (with

no guard bandsor guard periods)

Frequency Hopping Power SpectrumCDMA Mobile Technology Overview


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Frequency Hopping Power Spectrum

Time Averaged

Power Spectrum

Frequency

Frequency

Frequency

Frequency

Power

Power

Power

Power

Instantaneous Power

Spectra for a channel indifferent frames

CDMA at the Cocktail PartyCDMA Mobile Technology Overview


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CDMA at the Cocktail Party

We can actually be more sophisticated than this.

If we know the characteristics of the persons voice we can tune in towhat they are saying and ignore what other people are saying

This is like CDMA where the conversation/channel separation isprovided by the characteristics of the channel

i.e. the code

The only problem is that we do pick up some of the noise from theother channels This limits the number of conversations/channels that can use the same

medium

We also need to know the code in use

We need signaling to tell people their code This is sometimes called Direct Sequence Spread Spectrum


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CDMA Power SpectrumCDMA Mobile Technology Overview


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CDMA Power Spectrum

Power Spectrum for the

equivalent unspreadchannel

FrequencyFrequency

PowerPower

Power Spectrum post

spreading

Note: The power

spectrum has been

spread similar to that in a

Frequency Hopping

system

More CDMA permutationsCDMA Mobile Technology Overview


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p

Of course we can start getting a bit clever again...

CDMA/FDMACDMA Mobile Technology Overview


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frequency

time

code

Idealised

CDMA/FDMA(with no guard

bands)

CDMA/FDMA can be used to

provide multiple carriers OR

to provide Frequency DivisionDuplexing - separate carriers

for the uplink and downlink

CDMA/TDMA/FDMA...CDMA Mobile Technology Overview


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frequency

time

code

Idealised

CDMA/TDMA/FDMA(with no guard bands

or guard periods)

Combining CDMA and TDMA can be

used to provide Time DivisionDuplexing

CDMA SpreadingCDMA Mobile Technology Overview


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p g

Channel

Tx Bit Stream Rx Bit Stream

Air Interface

Chip Stream

Code Chip Stream Code Chip Stream

Essentially Spreading involves changing the symbol rate on the air interface

Identica

l codes

Spreading Despreading

P P

P

f

f

P

f

f

P

f

Spreading and DespreadingCDMA Mobile Technology Overview


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p g p g

Tx Bit Stream

Rx Bit Stream

Code Chip Stream

Code Chip Stream

Air Interface

Chip Stream

1

-1X

X

Spreading

Despreading

SpreadingCDMA Mobile Technology Overview


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p g

If the Bit Rate is Rb, the Chip Rate is Rc, the energy per

bit Eb and the energy per chip Ecthen

We say the Processing GainGpis equal to:

Commonly the processing gain is refereed to as theSpreading Factor

b

c

cb

R

REE .

b

cp

R

RG


Spreading in noise


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Channel

Spreading Code Spreading Code

Wideband Noise/Interference

Signal Signal

Tx Signal Rx Signal (= Tx Signal + Noise)

p g

The gain due to despreading of the signal over widebandnoise is the Processing Gain

P

f

P

f f

P

P

f

P

f

Types of CodesCDMA Mobile Technology Overview


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yp

There are essentially two typesof codes used in CDMA

networks: Channelisation Codes

Are used to separate channelsfrom a single cell or terminal

Scrambling Codes

Are used to separate cells andterminals from each other rather

than purely channels

Channelisation/scramblingcodes may be either:

short (the length of the code is

equal to the bit period)

long (longer than the bit period)

S1

S2

S3

C1 C2 C3

C1 C2 C3

C1 C2 C3


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Channelisation Code GenerationCDMA Mobile Technology Overview


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Channelisation codes can be generated from a Hadamard

matrix A Hadamard matrix is:

Where x is a Hadamard matrix of the previous level

For example 4 chip codes are: 1,1,1,1

1,-1,1,-1

1,1,-1,-1

1,-1,-1,1

xx

xx

Note: These two codes

correlate if they are time

shifted

Scrambling Code GenerationCDMA Mobile Technology Overview


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Scrambling codes are not orthogonal since they are not

synchronised to each other at the receiver Hence it is sufficient to use Pseudo Random sequences

Maximal length sequences used which repeat after 2R-1bits

R relates to the number of taps in the generator

Scrambles signals but can also be used to de-scramble

Sequences with different offsets do not correlate Generate a single code

Plan the offsets on the downlink (for CDMA one)

Scrambling Code GenerationCDMA Mobile Technology Overview


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1 2 3 R-1 R

1 2 3 4 5 OUTPUT1 0 1 0 1 -

1 1 0 1 0 1

0 1 1 0 1 0

0 0 1 1 0 1

1 0 0 1 1 0

0 1 0 0 1 1

0 0 1 0 0 1

0 0 0 1 0 0

Start value

for offset

Output sequence: 1,0,1,0,1,1,0,0,1,0,0,0,...

Orthogonality of CodesCDMA Mobile Technology Overview


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If orthogonal mean interference power over a bit is zero

Sum = 0=> Orthogonal

Sum = 1=> Correlated

Sum = -0.75=> Non-orthogonal

Bit Period Chip Period

X

1

-1

0.25

-0.25

0.25

-0.25

Code

Signal Chip Stream

Bit Value

Multi Channel Spreading andDespreading



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Despreading

Channelc1 c1

c2 c2

P

f

P

f

P

f

P

f

P

f

P

f

f

P

f

P

Since the channels are orthogonal the resultinginterference is entirely removed by the despreadingprocess

CDMA in CellularCDMA Mobile Technology Overview


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Cellular systems have multipath channels with a delayspread

Channels from the same transmitter are no longer perfectlyorthogonal

Channelisation codes are no longer perfectly synchronised

Downlink Channels on the same cell interfere with each other

Worst case scenario can be treated as white noise

Otherwise use orthogonality factor (0.6 in urban macrocellstypically)

The orthogonality factor gives the percentage of interference that is

rejected


104/224

Visualising the Processing GainCDMA Mobile Technology Overview


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W/Hz W/Hz W/Hz

W/Hz W/Hz dBW/HzEb

Io

Ec

Io

Eb

Io

Eb/Io

Eb

No

Eb/NoEb

No

W/Hz dBW/Hz

Signal

Intra-cell Noise

Inter-cell Noise

Before

Spreading

After

Spreading With Noise

After

Despreading

/Correlation

Post

Filtering

Orthog = 0

Post

FilteringOrthog > 0

f f f

f f f

f f

A Channelised TransmitterCDMA Mobile Technology Overview


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Channel 1Bit Stream

Channel 2

Bit Stream

Channel 3

Bit Stream

Pulse Shaping

and Modulation

c1

c2

c3

s1Typically in a multi-channel transmitter,

channels are first spread and channelised

using the channelisation codes, then

combined and finally scrambled together.


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CDMA Noise CalculationCDMA Mobile Technology Overview


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We can say (approximately - assuming perfect powercontrol) that the Eb/Nois equal to:

Where:

Eb/No= Energy per bit/Noise Power Spectral Density M = Number of Users or Codes Used

h= Loading factor in the cell

Gp= Processing Gain

v = Voice activity factor

= Orthogonality Factor

i = the other to own cell interference ratio

h

v

1

i1

1G

M

1

N

Ep

0

b

CDMA Capacity CalculationsCDMA Mobile Technology Overview


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y

The Eb/Norequired to achieve a desired BER can becalculated/simulated for a given receiver

We can say that the number of users we can support isapproximately equal to:

h

v

1

i1

1G

NE

1M p

required0

b

CDMA Capacity CalculationsCDMA Mobile Technology Overview


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However imperfect power control will create a 30-40%

reduction in the capacity on the uplink (downlink channelswill always be ideally weighted)

Soft handover also impacts the capacity on the downlink -approximately 20-40% of channels will be required forhandover

Control and pilot channels require transmitted power -again impacting the downlink

Pilot ChannelsCDMA Mobile Technology Overview


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Pilot channels are effectively channels used in the cell

selection process Pilots contain no baseband information - no bits

The pilot is spread by the all 1s channelisation code Effectively the pilot is the scrambling code

The required pilot channel SNR is referred to in Ec/Io Pilots allow channel estimation

In cdmaOne the pilot also gives the mobile phase andtiming information

Soft HandoverCDMA Mobile Technology Overview


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Soft Handover is where more then one cell is incommunication with a terminal

The cells in communication with the terminal are known asan active set

The best serving cell is known as the primary cell- andmaintains the primary channel

Other channels are known as handover channels The gain associated with soft handover is known as the

macrodiversity gain

This occurs due to the uncorrelated nature of fast fading between

cells and the variation in slow fading between cells Note that slow fading is not entirely uncorrelated for different cells

Hard Handover (e.g.GSM)CDMA Mobile Technology Overview


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HandoverHysteresis

Margin

RX_Lev

Direction of Travel

Cell A Cell BA hard handover

between cells A and

B in GSM

In a hard handover

the mobile is only

ever

instantaneously

connected to a

single cell

Distance

Soft Handover (e.g. in cdmaOne)CDMA Mobile Technology Overview


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Active set = 1 = 2 = 1Pilot Ec/Io

T_ADD

T_DROP

Cell A Cell A and Cell B Cell B

Direction of Travel

Add Time Delay Drop Time Delay

A soft handover

between cells A and

B in cdmaOne

In a soft handover

the mobile is may

be instantaneously

connected to more

than one cell

Distance

Why Soft Handover is Good in CDMACDMA Mobile Technology Overview


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Why Soft Handover is Good inCDMA

Near- Far Effect

Hard Handover can lead torelatively deep penetration intoneighbour cells

Soft Handover allows PowerControl from all Active Set cells

Probability of dropped callreduced due to link redundancyin handover region

Macrodiversity gain

Why Soft Handover is Bad inCDMA

Transmission overhead inbackhaul

Addition of downlink noise intothe system

Engineering of handover zones

becomes highly critical


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Cell BreathingCDMA Mobile Technology Overview


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An increase in traffic results is an increase in interference

Mobiles at the extremities of cells may be pushed out ofthe cells effective coverage area due to decreased Eb/No

This effect may occur over the course of 24 hours due tochanges in traffic demand over peak hours

6am Noon 9pm

More CDMA at the Cocktail Party -Power Control



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Power Control If somebody is shouting louder than they need it increases

the overall noise This is inefficient as it reduces the number of people who

can have conversations

We need to speak as quietly as possible to maximise the

number of simultaneous This is called Power Controlin mobile networks

In CDMA networks it is very important that this powercontrol is efficient

We use fast power control with a much quicker feedback loop thanin TDMA networks


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QuestionsCDMA Mobile Technology Overview


120/224


What is a pilot channel?

How does soft handover differ from hard handover? How do scrambling codes differ from channelisation

codes?

Why is multipath fading bad from a CDMA point of view?

Session SummaryCDMA Mobile Technology Overview


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In this session we have discussed:

CDMA and how it relates to and differs from other multiple accesstechnologies

What channelisation and scrambling codes are and what they do

What we mean by a pilot channel

How soft handover works

What we mean by cell breathing and the near far effect


122/224



123/224



Contents and Session AimsUMTS Architecture Overview


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This session aims to give theuser a first pass overview of the

architecture behind UMTS To explain the major

architectural blocks

To give a first introduction to themajor network elements and

interfaces To talk about how UMTS will

interface with existingtechnologies

UMTS High Level

ArchitectureThe Core Network

UTRAN

The User Equipment

Interfaces

Access ModesUMTS and GSM

Public Land Mobile Network (PLMN) A Public Land Mobile Network is



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A Public Land Mobile Network isdefined in the specifications asconsisting of:

One or more switches with acommon numbering plan androuting plan

Switches act as the interfacesto external networks

A PLMN can be regarded as anindependenttelecommunications entity

The PLMN can be separatedinto

Core NetworkAccess Network

Core Network

Access Network

PLMN


UMTS High Level Architecture


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User Equipment

UMTS

TerrestrialRadio Access

Network

Core Network

UU IUUE UTRAN CN

To this definition, the 3GPP standards add an additionalarchitectural block, the User Equipment

Major Network Elements in UMTS



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UU IU

UE UTRAN CN

CU

IUb

IUr

USIM

ME

Node B

Node B

Node B

Node B

RNC

RNC

MSC/VLR

SGSN GGSN

GMSC

HLR

PLMN,PSTN,

ISDN

Internet,

X25

Packet

Network

Mobile

Equipment

UMTS SIM

Radio

Network

Controller

Radio

Network

Controller

Serving

GSNGateway

GSN

Gateway

MSC

Mobile

Switching

Centre

Home

Location

Register

Iu-ps

Iu-cs

IUb

Functions of the CNUMTS Architecture Overview


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Switching

Service Provision Transmission of user traffic between UTRAN(s) and/or

fixed network

Mobility Management

Operations, Administration and Maintenance

Major Elements of the Core NetworkUMTS Architecture Overview


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Home Location Register (HLR)

The database storing the master copy of a users profile Visitor Location Registor (VLR)

The database holding a copy of a visiting users profile

Mobile Switching Centre (MSC) Switch for Circuit Switched Services

Gateway MSC

Serving GPRS Support Node Router for Packet Switched Services

Gateway GSN

General Core Network ArchitectureOther MSC



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IUCN

MSC/VLR

SGSN GGSN

GMSC

HLR

Serving

GSNGateway

GSN

GatewayMSC

Mobile

SwitchingCentre

Home

Location

Register

Other SGSN

Other MSC

UTRAN

UTRAN

External

CircuitSwitched

Networks

External

Packet

Switched

Networks

Iu-cs

Iu-ps

Gs

Gn

Gn

Gr Gc

DD

Gi

FF

Functions of UTRANUMTS Architecture Overview


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Provision of Radio Coverage

System access control Security and privacy

Handover

Radio resource management and control

Elements of UTRANUMTS Architecture Overview


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Radio Network Controller

Owns and controls radio resources in its domain Service Access point for all services that UTRAN provides the CN

Node BActs as the radio basestation

Converts the data flow between the Iuband Uuinterfaces

General UTRAN ArchitectureUMTS Architecture Overview


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UU IU

UTRAN

IUb

IUr

Node B

Node B

Node B

Node B

RNC

RNC

Radio

Network

Controller

Radio

Network

Controller

Iu-ps

Iu-cs

IUb

CN (MSC)

CN (SGSN)

UE

Functions of the UEUMTS Architecture Overview


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Display and user interface

To hold the authentication algorithms and keys User end termination of the air interface

Application platform


135/224

General UE ArchitectureUMTS Architecture Overview


136/224


UU

UE

CU

USIM

ME

Mobile

Equipment

UMTS SIM

UTRANTerminal

Equipment

Major Interfaces in UMTSUMTS Architecture Overview


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There are four major newinterfaces defined in UMTS

IuThe interface betweenUTRAN and the CN

Iur

The Interface between

different RNCs Iub

The interface between theNode B and the RNC

Uu

The air interface

RNC

Node-

B

RNC

UE

CN

Uu

Iu

Iub

Iur

Iu - the Core Network to UTRAN InterfaceUMTS Architecture Overview


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There are two parts to the Iuinterface

Iu-psconnecting UTRAN to thePS Domain of the CN

Iu-csconnecting UTRAN to theCS Domain of the CN

No radio resource signalling

travels over this interface The Iuinterface divides the

UMTS network into the radiospecific UTRAN and the CNresponsible for switchingrouting and service provision

RNC

Node-

B

RNC

UE

CN

Uu

Iu

Iub

Iur

Iur- the Inter-RNC InterfaceUMTS Architecture Overview


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The Iurinterface allows softhandovers between Node-Bs

attached to different RNCs It is an open interface to allow

the use of RNCs from differentmanufacturers

Its functions may besummarised: Support of basic inter-RNC

mobility

Support of Dedicated andCommon Channel Traffic

Support of Global ResourceManagement

RNC

Node-

B

RNC

UE

CN

Uu

Iu

Iub

Iur

Iub- the RNC to Node-B InterfaceUMTS Architecture Overview


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The Iubis an open interface toallow the support of different

manufacturers supplying RNCsand Node-Bs

Its major functions are: Carries dedicated and common

channel traffic between the

RNC and the Node-B Supports the control of the

Node-B by the RNC

RNC

Node-

B

RNC

UE

CN

Uu

Iu

Iub

Iur

Uu- the Air InterfaceUMTS Architecture Overview


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Clearly the Uumust bestandardised to allow multiple

UE vendors to be supported bya network

The major functions of the Uuare to:

Carry dedicated and common

channel traffic across the airinterface

Provide signaling and controltraffic to the mobile from theRNC and the Node-B

RNC

Node-

B

RNC

UE

CN

Uu

Iu

Iub

Iur

UMTS Interface ImplementationUMTS Architecture Overview


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ATM/IP Network

RNCNode

B

NodeB

Node

B

MSC

RNC

SGSN

NodeB

IubIu_csIu_ps

Iur

Access Modes for UMTSUMTS Architecture Overview


143/224


In this course we will concentrate on the UMTS FDD airinterface

However we should bear in mind that a number of otheraccess modes are possible

Within UTRAN

Outside of UTRAN

Access Modes within UTRAN



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There are four access modes that will be contained withinrelease 2000 of the 3GPP standards

Direct Sequence FDD Mode 1

Based on UMTS FDD air interface

Multi Carrier FDD Mode 2

Based on cdma2000

TDD Mode

Based on UMTS TDD air interface

ODMA

Supplement to UMTS TDD mode based on using a second UE as a

radio relay

Additional Access Networks

Th UMTS CN i b i



145/224


The UMTS CN is beingdesigned with the possibility

of interfacing to additionalAccess Networks other thanUTRAN

GRAN - GSM/GPRS RadioAccess Network

ERAN - EDGE RadioAccess Network

BRAN - Broadband RadioAccess Network(HIPERLAN2)

DECT - Digital Enhanced

Cordless Telephony

UMTS-CN

DECT

BRAN GRAN

ERAN

UTRAN

UMTS and GSMInternet PSTN



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RBS

RNC

Node-B

Iub

RBS RBS RBS

RNC

Node-B Node-B

UTRAN

CoreNetwork

SGSN MSC

GGSN

Iu-csIu-psIu-cs

Iu-ps

IubIub

BSC

BTS

Iur

A-bis

A

Gb

GMSC

BSS/

Architecture of a UMTS bearer service

CN C



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TE TEUE UTRANCN

edge node

CNgateway

End-to-End Service

TE/UE Local

Bearer Service UMTS Bearer Service

Radio Access Bearer Service

External Bearer

Service

CN Bearer

Service

Radio Bearer

Service

IuBearer

ServiceBackbone Network

Service

UTRA FDD/TDD

ServicePhysical Bearer

Service

UMTS Protocol Stratums

I d t id


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In order to provideseparation between radio

access functionality andservice quality provision,protocols in UMTS aredivided into two stratums

Access Stratum

Encompasses layers 1and 2 of the OSI 7 layer

model, and the lower part oflayer 3

Non-access Stratum

Encompasses layers 4 to7 of the OSI 7 layer model,and the upper part of layer 3

N

onAccessStratum

AccessStratum

L1 L1 L1L1

L2L2L2L2

L5L5

L4L4

L6 L6

L7 L7

L3 lower L3 lower L3 lower L3 lower

L3 upper L3 upper

Uu IuUE UTRAN CN

Questions

Wh t l t d UTRAN i t f?



149/224


What elements does UTRAN consist of?

What is the primary role of UTRAN? What additional access modes does UMTS support over

UMTS FDD?


150/224

Locator Slide

Introductory Session Day 2 Introductory Session

UMTS Air Interface


151/224







UMTS Air Interface

Day 1 Roundup


UTRAN

UMTS Core Network


UMTS Mobiles

UMTS Services

Course Roundup

UMTS Air Interface


152/224


UMTS Air Interface


UMTS Air Interface

This session aims to explain the

O i f th Ai


153/224


This session aims to explain theprotocols and operation of the

air interface To give an overview of the

UMTS specific operation of theair interface

To look at the protocol structure

To investigate the Frame andTimeslot structure of the majorair interface channels

Overview of the Air

Interface

Logical, Transport and

Physical Channels on

the Air Interface

The Dedicated

Channels

Role of the Air Interface

To provide a number of bearer or physical channels to

UMTS Air Interface


154/224


support data transfer over the radio path.

To provide control channels to manage the cell To provide a number of traffic channels at an acceptable

error performance and at various rates

To provide signalling channels for call set up, etc.

In providing all of this to also: Ensure an efficient use of the available spectrum

Minimise interference to other cells and services

Minimise the use of power, particularly from the mobile

Provide synchronisation

UMTS FDD Air Interface Overview

UMTS Air Interface


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Parameter Value

Multiple Access Scheme Direct Sequence CDMADuplexing Method FDD

Chip Rate 3.84 Mcps

Carrier Spacing 5 MHz

Carrier Spacing Raster 200 kHz

Frame Length 10 ms

Slots per Frame 15

Inter-cell Synchronisation NoneSpreading factor Variable (4-512)

User Data Rate 8->384 kbps

Multiple Access Scheme

UMTS FDD mode makes use of a CDMA style multiple

UMTS Air Interface


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UMTS FDD mode makes use of a CDMA style multipleaccess scheme

In the case of UMTS this is commonly referred to asWideband CDMA

However there are elements of FDMA and TDMA inUMTS

Common channels for paging and packet access share codesbetween UEs (TDMA)

Multiple carriers are used per operator (FDMA)

Duplexing Method

UMTS FDD mode makes use

UMTS Air Interface

190MHz


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UMTS FDD mode makes useof Frequency Division

Duplexing The Uplink and Downlink

Channels are carried onseparate carriers

In the case of UMTS in

Europe: The Uplink band is between

1.92 and 1.98GHz

The Downlink band isbetween 2.11 and 2.17GHz

The Uplink/DownlinkSeparation is 190MHz

190MHz

UMTS Uplink UMTS Downlink

Chip Rate

The chiprate used in UMTS FDD mode is 3 84Mcps

UMTS Air Interface


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The chiprate used in UMTS FDD mode is 3.84Mcps

This leads to a carrier bandwidth of approximately 5MHz

This chip rate was chosen because it: Could be generated simply from existing GSM clock rates

Provided a similar bandwidth to cdma2000 to allow shared use of filtersetc in UEs

Note:Initially UMTS was specified as having a chip rate of4.096Mcps. You may find some old texts and papers referring to this chip rate

Carrier Spacing and Carrier SpacingRaster

Th i l i i f

UMTS Air Interface

5MHz


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The nominal carrier spacing forUMTS is 5Hz

This was chosen to comply withthe American market, wherespectrum has been awarded in5MHz blocks

It is possible to move the centrefrequency of the carrier on a200kHz raster

We can have carrier spacingsbetween 4.4MHz and 5.6MHz

This may be set within the

license conditions, or to theoperators discretion

200kHz

Adjacent Channel Interference

Adjacent channel interference may have a significant

UMTS Air Interface


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Adjacent channel interference may have a significantimpact on UMTS capacity

Required attenuation (by standards) adjacent carrier 33dB

2nd adjacent carrier 43dB

Since only have 2 or 3 carriers typically at least oneadjacent carrier will be transmitted by a third party

This can partially be negated by a flexible carrier spacingbased upon a 200kHz raster

Adjacent Operator Interference

UMTS Air Interface


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Distant Serving

Macrocell

Close

Interferring

Microcell

Interference

Signal50dB path loss

150dB path loss

UK Spectrum Allocations Example

D D DE E EC C CA A A A B B B

UMTS Air Interface


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16

U101 UMTS Network Systems Overview

Hutchison

One2One

Vodafone

BT Cellnet

Orange

14.6MHz 14.8MHz10MHz 10MHz 10MHz0.3MHz0.3MHz

20MHz

Radio Frame Structure

Radio Frame Period = Tf = 10ms

UMTS Air Interface


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16


Tslot = 666.7ms = 2560 chips

Radio Frame Period = Tf = 10ms

Frames are used for channel format control 15 slots, #0#14

Slots are used for power control

38400 chips

Tslot= 2560 chips = 666.7ms

#0 #1 #2 #i #14

Tf = 10ms = 38400 chips

Superframe Structure

72 Radio Frames make a Superframe

UMTS Air Interface


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16


72 Radio Frames make a Superframe

Superframe Period Tsf= 720msSuperframes are used for

#0 #1 #2 #i #71

Tsf = 720ms

Inter Cell Synchronisation

Cells in a UMTS network are not synchronised in time with

UMTS Air Interface


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16


Cells in a UMTS network are not synchronised in time witheach other.

This removes the need for tight synchronisation betweenthe base stations

There is no need for GPS receivers at sites This makes implementation of picocells and their integration with

the network more simple as satellite LoS is not required

3rd Party Transmission requirement are less stringent

Spreading Factor and User Data Rates

UMTS has been designed to provide flexibility to allow the

UMTS Air Interface


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16


UMTS has been designed to provide flexibility to allow theuser to use multiple services, some of which we cannot

foresee at the moment

Rather than having a fixed bit rate and spreading factor,each of the channels on the user interface has a range ofbit rates that can be used

This makes the channels more complicated than forGSMbut certainly more flexible

Air Interface Access Stratum

L3Radio

ResourceControl Plane

Si lliUser Plane

UMTS Air Interface


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16


L3

L2

L1

Resource

Control RRC

Radio Link

Control RLC

Medium Access

Control MAC

Physcial Layer

Signalling Information

Logical

Channels

Transport

Channels

Physical

Channels

Radio Resource Control Layer

The RRC layer forms the lower

UMTS Air Interface


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16


Physical

Channels

ypart of the OSI layer 3

It is responsible for: Bearer Control

Monitoring

Power Control

Measurement Reporting Paging

Broadcast Control

L3

L2

L1

RadioResource

Control RRC

Radio Link

Control RLC

Medium

Access Control

MAC

Physical Layer

Control PlaneSignalling

User PlaneInformation

Logical

Channels

Transport

Channels

Radio Resource Control LayerFunctional Entities

The RRC layer resides at the RNC serving a cell or UE

UMTS Air Interface


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16


The RRC layer resides at the RNC serving a cell or UE

The RRC Layer can be split into 3 functional entities Dedicated Control Functional Entity (DCFE)

One per UE in connection

All functions and signalling specific to a single UE

Paging and Notification control Functional Entity (PNFE)

One per cell

Paging of idle mode UEs

Broadcast Control Functional Entities (BCFE)

One per cell

Broadcasting of system information

Radio Link Control Layer

The RLC layer forms the upper

UMTS Air Interface


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17


Physical

Channels

y pppart of the OSI layer 2

It is responsible for: Logical Link Control

Acknowledged andunacknowledged data transfer

L3

L2

L1

Radio

Resource

Control RRC

Radio Link

Control RLC

Medium

Access Control

MAC

Physical Layer

Control PlaneSignalling

User PlaneInformation

Logical

Channels

Transport

Channels

The Medium Access Control Layer

The MAC Layer forms the lower

UMTS Air Interface


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17


Physical

Channels

ypart of layer 2

It is responsible for: Random Access

Physical Link Control

Ciphering

Multiplexing and ChannelMapping to the Physical Layer

L3

L2

L1

Radio

Resource

Control RRC

Radio Link

Control RLC

Medium

Access Control

MAC

Physical Layer

Control PlaneSignalling User PlaneInformation

Logical

Channels

Transport

Channels

Medium Access Control LayerFunctional Entities

MAC-b

UMTS Air Interface


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17


Handles the broadcast channel (BCH) and is located in the Node-B in the UTRAN

MAC-c/sh Handles the common and shared channels and is located in the

RNC in the UTRAN

MAC-d Handles the dedicated channels and is located in the RNC

The Physical Layer

The Physical Layer forms layer

UMTS Air Interface


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17


2 of the OSI protocol stack

It is responsible for: Carrying traffic and signalling

across the air interface

L3

L2

L1

Radio

Resource

Control RRC

Radio Link

Control RLC

Medium

Access Control

MAC

Physical Layer

Control PlaneSignalling User PlaneInformation

Logical

Channels

Transport

Channels

Physical

Channels

Protocol Termination in the AccessStratum

UMTS Air Interface


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17


User Equipment Node-B Radio Network Controller

RRC RRC

RLCRLC

MAC MAC

Physical Physical

Note:Some Layer 2 functionality regarding the

broadcast functionality resides in the Node-B

UMTS Channel Types and Functions

There are three types of channel across the air interface

UMTS Air Interface


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17


ypand access stratum that we are interested in:

Logical Channels

Between the RLC and MAC layers

Transport Channels

Between the MAC and Physical layers

Physical Channels

Between Physical Layers at the Node-B and UE

Major Logical Channels in UMTS

Control Channels

UMTS Air Interface


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17


BCCH Broadcast Control Channel

PCCH Paging Control Channel

CCCH Common Control Channel

DCCH Dedicated Control Channel

Traffic Channels DTCH Dedicated Traffic Channel

CTCH Common Traffic Channel

Logical Control Channels

The Broadcast Control Channel(BCCH) is a downlink

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( )channel for broadcasting system control information

The Paging Control Channel(PCH) is a downlink channelthat transfers paging information

The Dedicated Control Channel(DCCH) is a point-to-pointbi-directional channel transmitting control information

between a specific UE and the UTRAN

The Common Control Channel(CCCH) is a bi-directionalchannel transmitting control information between Ues andthe UTRAN

Logical Traffic Channels

The Dedicated Traffic Channel(DCH) is a point-to-point

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( ) p pchannel dedicated to a single UE for the transfer of user

information

The Common Traffic Channel(CTCH) is a point-to-pointunidirectional channel for transfer of user information to agroup of UEs

Common Control Channels

Major Transport Channels for UMTS

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BCH Broadcast Channel

FACH Forward Access Channel

PCH Paging Channel

RACH Random Access Channel

CPCH Common Packet Channel

Dedicated Channels DCH Dedicated Channel

DSCH Downlink Shared Channel

Common Transport Channels

The Broadcast Channel(BCH) is a cell-wide channel that is used tob d t t d ll ifi i f ti Th BCH i l

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broadcast system and cell-specific information. The BCH is always

transmitted over the entire cell with a low fixed bit rate. The Paging Channel(PCH) is a cell-wide channel that is used to carry

control information to a UE when the system does not know thelocation cell of the UE

The Forward Access Channel(FACH) is a downlink channel that is

used to carry control information to a UE when the system knows thelocation cell of the UE. May also carry short user packets.

The Random Access Channel(RACH) is an uplink control channelfrom the UE. May also carry short user packets

The Common Packet Channel(CPCH) is a contention based uplink

channel used for transmission of bursty data traffic.

Dedicated Transport Channels

The Downlink Shared Channel (DSCH) is a downlink

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channel shared by several UEs carrying dedicated control

or traffic data.

The Dedicated Channel (DCH) is a channel dedicated toone UE used in uplink or downlink.

Common Control Channels P-CCPCH Primary Common Control Physical Channels (DL)

Major Ph

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