Mobile Networks Overview & 2G Standards Comparison

Frequency Division Multiple Access... Time Division Multiple Access... The Cocktail Party Analogy 2/3FDMA, TDMA vs CDMA... Main 2G standards GSM  TDMA air interface  Complete system R

Mobile Networks Overview & 2G Standards Comparison

Cellular Networks

Omni-directional

Unidirectional

Cellular Networks History

 1 st Generation: Analog Networks

 2 nd Generation: Digital Networks

 1992 Europe GSM 900 / GSM 1800

 3 rd Generation: Federative Standards

 idem USA IMT 2000: EDGE + CDMA2000

Types of Cells forDifferent Applications

e a s y 0 6

BSC

B T

T S

B T S

B T S

BSC

Air Interface Multiple Access Scheme

FDMA, TDMA & CDMA

Ch 2

Ch 3

Frequency Division Multiple Access

Time Division Multiple Access

Code Division Multiple Access

Pseudo-Random Code Sequence

 All users use the entire carrier

all of the time !!

 “Spread Spectrum” technology

 1 user = 1 Unique digital code

 Other users = Noise

 Applications

 Digital Cellular (IS-95)

 Satellite (Globalstar)

Multiple Access Scheme

CDMA

Time

The Cocktail Party Analogy 1/3

 Partygoers = Cellular users

 1-to-1 conversation = Com.

 Room = Frequency

The Cocktail Party Analogy 2/3

FDMA, TDMA vs CDMA

The Cocktail Party Analogy 3/3

CDMA

 People from many nations

 Phenomenal translator

 More partygoers => noisier room

 Noise interferes with conversations

 “Area of comfortable conversation” (QoS) decreases

Main 2G standards

 GSM

 TDMA air interface

 Complete system (Radio Access & Core Network)

 From Europe but with world-wide success

 GPRS for High Speed Data

 US-TDMA (D-AMPS), IS-136, TDMA

 CDMAOne, IS-95, CDMA

 Air interface only + IS-41 for Core Network

 From the USA and little export success

 PDC

 Japanese system

2G StandardsGSM, IS-136 (D-AMPS) & IS-95 (CDMA)

Cellular Frequency Spectrum Allocation

Max Possible Data

Rate 160 Kbit/s 43.2 Kbit/s 115.2 Kbit/s

X.2 5

ISUP/

R2 E1 MAP

A E1 E1

Air interfac

e (TDMA)

GSM is a Network Standard

All interfaces & NE’s are specified

A bis

(no SIM, PIN)

X.2 5

ANSI#7 T1 IS41

IS634 T1 T1

IS95

CDMA is a Radio Standard

Only 3 interfaces are specified

Mono supplier network

GSM Key Advantagesover CDMA & TDMA

 International Roaming

 More voice & data services

 Voice Quality & Privacy

 Cost-efficient equipment &

wider scale

 Future-Proof technology: On

the road to 3G: EDGE & UMTS

 Easier network optimisation

GSM Key AdvantagesThe Major World-wide Standard

TDMA 8%

PDC 9%

Analog 15%

304 Mio GSM

Subs (03/00).

304 Mio GSM

Subs (03/00)

GSM AdvantagesLess Investment

Cost-efficient equipment

 Cheaper infrastructure (2.5 less than CDMA)

 Less sites than CDMA & D-AMPS

 Internet & Data ready (W@AP, GPRS, E-GPRS)

 Investment protection for 3G: EDGE & UMTS

 Transmission reuse in ETSI countries

GSM AdvantagesLess Operating Costs

CDMA Cell breath

Coverage, Capacity & Quality Issues (1/2)

Coverage, Capacity & Quality Issues (2/2)

 1.5 Million subscribers

 World’s largest CDMA service provider

 SK Telecom General Manager of the digital CDMA Business

Div:

“It is not easy to optimize CDMA, cell boundaries change with the

growth of subscribers SK Telecom employed hundreds of personnel

day and night on the Optimization process”

Quotes (1/2)

SK Telecom (south Korea) Experience (Telephony/September 8, 1997)

 CDMA network in Chicago & Detroit

 Ameritech’s vice president for network planning:

“CDMA is extremely complex and that power management, frequency

reuse are all keys to Optimization Ameritech is overlaying CDMA on AMPS cells in downtown of Chicago and Detroit at a 1 to 1 ratio,

initial models said 1 to 3 , but it did not meet our satisfaction levels“

Quotes (2/2)

Ameritech (USA) Experience (Telephony/September 8, 1997)

GSM Key AdvantagesMore Revenues (1/2)

International Roaming

 900/1800/1900 world-wide (GSM Association: 141 countries-450 operators)

 IN based services available when roaming (via CAMEL)

 Standardised CDR exchange (TAP3)

More voice & data services

 GSM Supplementary services: AoC, CUG, CH, COLP, COLR

 Internet & Data services Inside with W@P & GPRS

Voice Quality & Security

GSM Key AdvantagesMore Revenues (2/2)

Cornerstone of GSM technology

 Uncoupling subscription from handsets (IMSI, MS-ISDN)

 Storing facilities: personal phone numbers, short messages

 Corporate management (FDN…)

 SIM Toolkit for personal applications

The Key for Security

 Handset free sophisticated Authentication & Ciphering

 Quasi impossible to clone

SIM Card (Subscriber Identity Module)

Mor e fl

exib le t

han CDM A &

D-A MPS

On the Road from GSM to UMTS

The Mandatory Step

The Evolutionary Step

 Multimedia (R’00)

UMTS: 3G

 Up to 2 Mbit/s

 Internet services (R’99)

 Multimedia (R’00)

Thank You for Your Attention