1st 2nd Generation Telecom Systems

1U101 UMTS Network Systems Overview

1st and 2nd Generation Cellular Systems Overview

1st and 2nd Generation Cellular Systems 1st and 2nd Generation Cellular Systems OverviewOverview


Contents and Session AimsContents and Session Aims1st and 2nd Generation Cellular Systems Overview

• This is a background session to set the scene for UMTS, essentially a cellular history lesson

• Firstly we will examine what we mean by cellular communications

• We will look at different generations of cellular and briefly at major standards

• This will allow us to see why 3G has moved forward in the way that it has

•What is Cellular?

•Cellular Generations•1st Generation•2nd Generation•2.5G


What is Cellular?What is Cellular?• There are three major types of

terrestrial mobile communications technologies

• Cellular! Users are provided wide area

mobility from multiple base stations with handover permitted

• Cordless Communication! Users are provided limited mobility

from a dedicated base station

• Paging! Brief numeric, alphanumeric or voice

messages are sent to the subscriber typically using simulcasting


PSTNMSCPaging Control Centre

Cellular

Cordless

Paging


Cellular GenerationsCellular Generations• People talk about mobile

technology in terms of generations! 1st Generation or 1G! 2nd Generation or 2G! 2.5G! 3rd Generation or 3G

• But what do these mean?


time

Data rate

Progress of data rates with time and generation


1st Generation1st Generation• 1976+, though really the

technology of the 1980’s• Analogue modulation• Frequency Division Multiple

Access• Voice traffic only• No inter-network roaming possible• Insecure air interface


The 1st Generation of Cellular Technology makes use of analog modulation techniques such as FM


1st Generation Standards1st 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 Planning1st 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 Generation2nd Generation• 1990’s• Digital modulation• Variety of Multiple Access

strategies• Voice and low rate circuit switched

data• Same technology roaming• Secure air interface


000110100110

1110

0100

1111

000

00100101111001111000101100000100100

The 2nd Generation of Cellular Technology is the first to use digital modulation



GSMGSM• First networks in 1992• European developed standard, but

with worldwide subscriber base• Different frequency bands

! GSM450, GSM900, GSM1800, GSM1900

• Largest 2nd Generation subscriber base

• Frequency/Time Division Multiple Access

• Open/Standardised Interfaces

GSM phones from 1999/2000


GSM PlanningGSM 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/traffic analysis! Capacity limited by number of

TRX’s

• Hard Handover


GSM networks use microcellsto provide additional capacity. As with 1st generation networks frequency planning is required


DD--AMPS/PDCAMPS/PDC• TDMA (D-AMPS)

! North American TDMA/FDMA based standard based upon AMPS

! Predominantly used in North and 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


cdmaOnecdmaOne• First networks in 1996• Derived from Qualcomm IS-95 air

interface• Largely American subscriber base

with some Asian networks• Code Division Multiple Access

! This is in many ways the closest 2nd generation standard to many of the 3rd generation standards

• ANSI-41 core network• Chip rate of 1.2288Mcps


cdmaOne phones from 1999/2000


cdmaOne PlanningcdmaOne Planning• Macrocells and microcells• Single Frequency

! multiple frequencies for hotspots

• Soft Handover (multiple connections between mobile and network)

• Code Planning• Capacity Interference Limited

1 Connection

2 Connections

3 Connections


Unlike GSM there is no frequency planning required for cdmaOneHowever soft handover means that there are zones where there are two/three connections to the network


Worldwide Mobile Communications in the Worldwide Mobile Communications in the 1990s1990s

0100200300400500600700

1991

1993

1995

1997

1999

2001

Second Generation -D-AMPSSecond Generation -PDCSecond Generation -GSMSecond Generation -cdmaOneFirst Generation -Analogue

Million S

ubscribers

Year Source:Wideband CDMA for 3rd Generation Mobile Communications, Artech House, 1998



Worldwide Mobile SubscribersWorldwide Mobile Subscribers

0

500

1000

1500

2000

1995 2000 2005 2010

European UnionCountriesNorth America

Asia Pacific

Rest of World

Million S

ubscribers

Year Source:Third Generation Mobile Communications, Artech House, 2000



2.5G2.5G• 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 or cdmaOne


2.5G technologies are based upon existing 2G technologies but are focussed at increasing the maximum data rates that the technologies can deliver


HSCSDHSCSD• 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 to 57.6kbps (4 slots with 14.4kbps channel coding per slot)

Nokia Cardphone



GPRSGPRS• General Packet Radio Service• Enhancement to the GSM standard• Utlilises

! Multiple Channel Coding Schemes (9.05kbps, 13.4kbps, 15.6kbps, 21.4kbps)

! Multiple Timeslots! Packet Switching

• Packet Switched Data typically to rates of 115kbps

! Theoretically 171.2kbps for 8 timeslots

Ericsson R520(available 1Q 2001)

Sagem MC850 Alcatel One Touch 700(available October 2000)



ISIS--95B95B• Enhancement to cdmaOne

standard• Utilises

! High rate coding scheme! Combined code channels! packet switching

• Packet Switched Data to rates of 114kbps


Qualcomm PDQ Smartphone


2G and 2.5G Standards Compared2G and 2.5G Standards ComparedGSM TDMA cdmaOne PDC

MultipleAccess

TDMA TDMA CDMA TDMA

Modulation GMSK π/4-DQPSK QPSK π/4-DQPSK

CarrierSpacing

200kHz 30kHz 1.25MHz 25kHz

Frame Length 4.615ms 40ms 20ms 20ms

Slots perFrame

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



QuestionsQuestions• What defines a 1st generation technology and a 2nd generation technology?• What is are the main differences between GSM and cdmaOne?• How do 2.5G standards relate to 2G standards?



Session SummarySession Summary• We’ve now set the scene - we can start talking about where

people want to go from here now…• The generations of cellular technology may be summarised:

! 1G is analog voice! 2G is digital voice! 2.5G is digital intermediate rate data

• You also know it’s the coffee break now…and to come back at 10:45!



IMTIMT--2000 Future Spectrum2000 Future SpectrumITU

(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

3rd Generation Drivers and Standards


IMTIMT--2000 Candidate Technology Evaluation2000 Candidate Technology Evaluation• The ITU issued a request for proposals for the Radio

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

• Following this a self evaluation of the RTT submitted was required by September 1998

• Candidate technologies were then evaluated according to their compliance with the goals for IMT-2000



IMTIMT--2000 Candidate 2000 Candidate HarmonisationHarmonisation• 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



3G Standardization Environment3G Standardization Environment3rd Generation Drivers and Standards

Key Players and their relationships in the IMT-2000 standardisation environment


• 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

IMTIMT--2000 Selected Air Interface Standards2000 Selected Air Interface Standards3rd Generation Drivers and Standards


• Three candidate technologies will be used:

! GSM MAP Evolved! ANSI-41 Evolved! IP Based

"Driven forward by 3GIP

IMTIMT--2000 Selected Core Network Standards2000 Selected Core Network Standards3rd Generation Drivers and Standards


IMTIMT--2000 Standards2000 Standards3rd Generation Drivers and Standards

The IMT-2000 family of standards


• 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 cdmaOne standard! PCS spectrum overlaps IMT-2000 band! Major Drivers

" Spectrum sharing and compatibility with 2G standard" National/International roaming

cdma2000 (cdmaOne operators)cdma2000 (cdmaOne operators)EDGE (TDMA operators)EDGE (TDMA operators)

North America DriversNorth America Drivers3rd Generation Drivers and Standards


• 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 no

spectrum sharing issues! EU enforced standardisation means UMTS for ‘at least 1 operator’ per

country! Major Drivers

" Higher Data Rates" Continued global dominance of European based standard

UMTSUMTS

European DriversEuropean Drivers3rd Generation Drivers and Standards


Japan/Korean DriversJapan/Korean Drivers• Japan and Korea

! PHS and PDC left Japanese manufacturers isolated! IMT2000 band compatible with current spectrum usage leads to no

spectrum sharing issues! Political US relationships...! Major Drivers

" Capacity for Voice" Global market for cellular infrastructure

UMTSUMTS



Cordless DriversCordless Drivers• You can’t get 2Mbps out of the cellular standards• Hence a requirement for cordless style standards

! UMTS TDD Mode! DECT



Industry Bodies Industry Bodies -- Radio RegulatoryRadio 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/



Industry Bodies Industry Bodies -- Trade AssociationsTrade 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 Communications Consortium! http://www.uwcc.org/



Industry Bodies Industry Bodies -- Standards GroupsStandards Groups• 3GPP

! UMTS FDD and TDD! Standards Development! http://www.3gpp.org/

• 3GPP2! cdma2000! Standards Development! http://www.3gpp2.org/

• 3GIP! IP Core Network! http://www.3gip.org/



Partnership Projects and Standards Partnership Projects and Standards OrganisationsOrganisations


Relationships between the standards organisations


3GPP Member 3GPP Member OrganisationsOrganisations• 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 Member 3GPP2 Member OrganisationsOrganisations• 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



The Road to 3GThe Road to 3G3rd Generation Drivers and Standards

Possible Evolution Paths to 3G

HSCSD


3rd Generation Cellular3rd 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 FDDUMTS FDD• Universal Mobile Telecommunications System Frequency

Division 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 Compared to GSMUMTS 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 NetworkOptimisation

Frequency Diversity 5MHz bandwidth givesmultipath diversity with

rake reciever

Frequency Hopping

Packet Data Load Based PacketScheduling

Time Slot basedScheduling with GPRS

Transmit Diversity Supported to improvedownlink capacity

Not supported bystandard but may be

applied



UMTS Compared to IS95UMTS 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 InterFrequencyHandovers

Yes, slotted modemeasurements

Possible butmeasurements not

specified

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 TDDUMTS TDD• Universal Mobile Telecommunications System Frequency

Division Duplexing Mode• Built onto enhanced GSM core network• Utilises:

! QPSK modulation! Multiple channel coding and bearer rates! CDMA! TDD! Asynchronous operation




cdma2000cdma2000• Built onto ANSI-41 core network• Utilises:

! QPSK modulation! Multiple channel coding and bearer rates! CDMA! FDD! Multiple carriers on the downlink to allow compatibility with cdmaOne! Synchronous operation




EDGEEDGE• 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 Standards ComparedUMTS FDD UMTS TDD cdma2000 EDGE

MultipleAccess

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 perFrame

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 DataRate

2Mbps 2Mbps 2Mbps 521/4750kbps

Synchronous No No Yes Yes

Handover Soft Hard Soft Hard



4th Generation...4th Generation...• Probably 2005-2007• Broadband data rates in excess of

1Mbps• Probably 10MHz+ carriers• ...



QuestionsQuestions• What is IMT-2000 and why is it related to UMTS?• Why do the American operators want cdma2000 and EDGE?• What is the major difference between UMTS and cdma2000?



Session SummarySession 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


1st 2nd Generation Telecom Systems

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