Evolution of Wireless Communication

By

Chandra Thapa

Evolution of Wireless Systems

Guglielmo Marconi invented the wireless telegraph in 1896Communication by encoding alphanumeric characters in

analog signalSent telegraphic signals across the Atlantic Ocean

First public mobile (car-based) telephone system (MTS) introduced in 1946Analog frequency modulation High power BS tower to cover 50 miles radius Inefficient (120K spectrum for a voice connection)

Evolution of Wireless Sys. (Contd)Improved mobile telephone system (IMTS) developed

in 1960Full duplex services and direct-dialing23 FM channels with BW reduced to 25-30 KHz

Cellular concept Exploits the attenuation of radio signal with

distance to achieve frequency reuse.originally proposed by D. H. Ring in 1947Bell Labs began work on cellular telephone system

in the late 1960s.

Evolution of Wireless Sys. (2.5G)2G telephony is highly successfulEnhancement to 2G on data service

GSM: HSCSD and GPRS IS-95: IS-95b IS-136: D-AMPS+ and CDPD

The improved data rate is still too low to support multimedia traffic

ITU initiated 3G standardization effort in 1992, and the outcome is IMT-2000.

Evolution of Wireless Sys. (1G)Handoff was not solved until the development of

microprocessor, efficient remote-controlled RF synthesizer, and switching center.

1G Cellular SystemDesigned in 1970s, deployed in early 1980sAnalog, 42 control channels, 790 voice channelsHandoff performed at BS based on received powerAMPS in US; TACS in part of Europe; NTT in Japan; C450

in West German, and NMT in some countries. Became highly popular; AMPS still popular in US!

Evolution of Wireless Sys. (2G)

2G Systems Digital cellular telephonyModest data support, incompatibleGSM: a common TDMA technology for Europe; claim

about 3/4 of subscribers worldwide. IS-54 and IS-136: TDMA technology in US; compatible

with AMPS; IS-95: CDMA; standardized in 1993; South Korea and

Hong Kong deployed it in 1995; US in 1996.

Evolution of Wireless Sys. (3G)IMT-2000 comprises several 3G standards:EDGE, data rate up to 473Kbps, backward compatible

with GSM/IS-136 cdma2000 (Qualcomm), data rate up to 2Mbps, backward

compatible with IS-95WCDMA (Europe), introduces a new 5MHz channel

structure; data rate up to 2Mbps;TD-SCDMA (China), CDMA in TDD fashion

Evolution of Wireless Sys. (4G)Problems of 3G systems

Immature 3G license auction increases the financial burden

Difficult to extend to higher data ratesNo unified standard (political factors dominate)

4G systemsResearch initiated, but still not well-definedData-oriented, seamless integrated with wirelineIndoor data rate up to 100 Mbps, outdoor data rate

up to 20Mbps.

Evolution of Mobile Radio Communications

AMPS

VoiceServiceTrack

CDMAIS-95

CDMA2000

4G

ETACS GSM

WCDMA

1st GenerationAnalog

2nd GenerationDigital

3rd GenerationWideband

FixedComputerNetwork

WLAN

PDMA

NorthAmerica

Europe

DataServiceTrack

Voice & DataServiceTrack

4th GenerationWideband All-IP

Notes:IP: Internet ProtocolTCP: Transmission Control ProtocolAMPS: Advanced Mobile Phone ServicesETACS: European Total Access Communication SystemPDMA: Packet Division Multiple Access (Hanwang, China)

Circuit Switching

Packet Switching

Circuit and Packet Switchingevolving to Packet Switching

TD-SCDMAChina

Trends in Wireless Comm. Personal Communications (Goal of mobile communications) All IP based (IPv6) (Packet switched) Flexible platform of complementary access

systems( Combination of different wireless access systems, Hot spot services will be introduced by high-speed wireless access (>100mbps))

Higher system capacity (Users/Service, 5-10 times higher than

3G) Higher Transmission Data rate Higher frequency efficiency More advanced multimedia applications Improved QoS Realize high levels of security and authentication Global coverage Global roaming

All IP Based

All IP based

Internet

PSTNISDN

IP/ATM/MPLS Backbone

Mobile Internet Application Platforms

Mobile InternetApplication Servers

Media Gateway

Mobility, Connection& Control Servers

Mobility Gateway Intelligent Edge

Broadband Gateway

IP MultiRadio

OWLAN

Broadband Accesses

Network Domain

Service Domain

Combination of different wireless access systems

IEEE.802.11 WLAN

WPAN WLAN WWAN

PAN Bluetooth PDMA

Network of 3G beyond

Services andapplications

IP based core network

IMT-2000UMTS

WLANtype

cellularGSM

short rangeconnectivit

y

WirelinexDSL

otherentities

DABDVB

return channel:e.g. GSM

download channel

New radiointerface

Transmission Data Rate Highest data rate(3G)

at least 144 Kb/s in a vehicular environment, 384 Kb/s in a pedestrian environment, 2048 Kb/s in an indoor office environment.

Highest data rate (4G) 2Mbps in a vehicular environment, 20Mbps in a pedestrian

environment Wide Area, high velocity： 100Mbps Indoor, lower velocity： 1Gbps

Evolution of transmission data rate

Drivers of 3G Beyond

3G evolution :Difficult

to extend to higher data rate with CDMA only technology;

to provide various services with different QoS

to have enough frequency resource to accommodate more subscribers

Drawback Low system capacity Low spectrum efficiency

MobileInternetUser

MobileUser

0

200

400

600

800

1000

1200

1400

1600

1800

1995 2000 2005 2010

Subscriptions (millions)MobileFixedMobile InternetFixed Internet

Drivers of 3G Beyond

3G2G

Revolution from subscriber service expectations

Evolution from 2G systems

IP

Revolution from IP infrastructure

and Beyond

Multimedia Services

Internet accessShopping/banking(e-commerce)Video conferencingVideo on demandTelemedicineDistance learning

Challenges

Unreliable ChannelsScarce Spectrum and Resource ManagementStringent Power BudgetSecurityLocation and RoutingInterfacing with Wired NetworksHealth ConcernDiversified Standards and Political Struggle