Wireless Communication Engineering

UNIT 1 PART 2

Wireless Billions of wireless devices are in use 4 wireless technologies in 10

communication technologies with most market potential: Wi-Fi UWB Software Radio Wireless Mesh Other six are: Nanotech, PON, Soft Switching,

MPLS, FSO, Optical Switching

EM Spectrum for Telecom Most spectra licensed; 3G license is very

expensive; FCC is a mighty sector Infrared, ISM band, and amateur radio

band are license-free HW2: Find out what spectrum is used for

GSM, IS-95, 802.11b WLAN. What data rates are available in each system? What transmission characteristics makes these spectrum bands suitable for wireless communications?

APPLICATIONS 1G – analog signals only ( ph call) 2G – sms 2.5G – mms, www ,email access (WAP) 2.75 – High data rate 3G – mobile internet, mobile tv, video

calling 3.5G – mobile broad bands, smart ph,

mobile modems 4G – IP telephony, ultra broadband modems

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

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

1G Cellular System Designed in 1970s, deployed in early 1980s Analog, 42 control channels, 790 voice channels Handoff performed at BS based on received power AMPS 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 telephony Modest data support, incompatible GSM: 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. (2.5G)

2G telephony is highly successful Enhancement 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. (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-95 WCDMA (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

What are the killer applications of 3G? No unified standard (political factors dominate)

4G systems Research initiated, but still not well-defined Data-oriented, seamless integrated with wireline Indoor 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

Paradigm From 1G to Beyond 3G

First Generation

• Analogue• Circuit switched• Basic voice

telephony• Low capacity• Limited local

and regional coverage

Second Generation

• Digital• Circuit switched• Voice plus basic

data applications• Low data speed• Enhancements

towards• packet switching• higher data rates

• Trans-national and global roaming

• Digital• Packet and circuit

switched• Advanced data

(multimedia) applications

• Fast data access• Global coverage• Global roaming

Third GenerationBeyond Third

Generation

• Digital• Packet switched• All IP based (IPv6)• More advanced

multimedia applications

• User in control• Flexible platform

of complementary access systems

• High speed data• Improved QoS• Global coverage• Global roaming

Mobility and Information Speed of Evolving Mobile Communication Systems

4G

High_speed

High_capacity

Low bit cost

3G

2G IMT-2000

Mob

ility

High Speed/Nationwide

Moderate Speed/Citywide

Walking/Premises

Static/Indoor

(2001)

(2007-2010?)

0.1 1 10 100

Infomation Speed(Mbit/s)

(2002)

wireless accessMillimeter_wave

LAN

Trends in Wireless Commun.• 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 beyondServices 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

2G 3G and beyond

9.6-14.4 kbps

evolved 2G

64-144 kbps 384 kbps-2 Mbps 100 Mbps?384 kbps-20 Mbps

System Capacity and spectrum efficiency

Capacity: 5-10 times higher than 3G

Frequency efficiency: Multi-cell: > 2bits/Hz

Single-cell: 5~10 bits/Hz

Drivers of 3G Beyond

3G evolution …but 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

0

25

1998 1999 2000 2001

50

75

100

125

150Pbit/day

Real Time(e.g. Voice)

Non Real Time(e.g. Internet access)

MobileInternetUser

MobileUser

0200400600800

10001200140016001800

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

0

5

10

15

20

25

1999(Forecast by ITU-R TG-8/1 for Asia)

2015(Extrapolation)

Up Down Up Down Up Down

63%

23?

5.4

1

19.8

10 ％

30%

15%

28%

8%3.4

0.50.5

91 %

Multimedia (U:128k,D:10Mbps) (U:128k, D:2Mbps) (U:64k,D:384kbps) (U/D:128kbps×n)

1G/2G servicesVoice (U/D: 16k, VOX0.5)Others (<64 kbps)

9 %

Multimedia traffic increases 40%/year. 10Mbps downstream service emerges. Saturation of 1G/2G services traffic.

Subscribers ×1.5

Voice : Multimedia traffic ratio 1 : 2 (in 2010)

3.9

1.5

Rel

ativ

e tr

affi

c va

lue

in b

its

(Ref

: 19

99)

Year2010

Service Forecast for Asia Region

Multimedia Services

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

Challenges Unreliable Channels (Cross Layer Design) Scarce Spectrum and Resource

Management Stringent Power Budget Security Location and Routing Interfacing with Wired Networks Health Concern Diversified Standards and Political Struggle