Wireless Communication Engineering

(Fall 2004)

Lecture 1

Professor Mingbo Xiao

Sept. 23, 2004

Let’s Know Each Other My Self-Introduction Course Objectives and My Wishes Your Self-Introduction (Name, Major,

Reasons for taking this course, etc.) Suggestions are always welcome and

sometimes required

Recommended Background Digital Communications Computer Networks Probability and Stochastic Processes

Grading Final (Exam/Project/Paper) 34% Midterm 33% Homework +Quiz 33%

NO late submission or any type of cheating is allowed in this class.

Homework is due before the next lecture starts.

What’s QUIZ?

QUIZ is also known as POP QUIZ. It’s a very nice way for the teacher

to find out who is absent. It is usually unannounced :-B. When you find out its real meaning,

you may want to say it like QUIZzzzzzzzzzz

Still unclear?

QUIZ #1

Given two boxes of GO chesses. Put a handful of the black chesses into the white box, mix them, and then take a handful of the mixed chesses back to the first box.

Question: Which one is larger, the number of black chesses in the white box or the number of white chesses in the black box?

How about Homework?

Homework is different from quiz in that you can answer it off the class.

HW1: Answer the following questions in no less than 500 English words: What do you expect to learn from this

course? Any plan on how to achieve it? What are your opinions on the bilingual

teaching for a major course like this one?

Textbook and References Wireless Communication and Networks

(by William Stallings; ISBN: 0-13-040864-6; Publisher: Prentice Hall, 2002)

Wireless Communication and Networks (by Weihua Zhuang etc., Chinese edition)

Principles of Wireless Networks: A Unified Approach (by Kaveh Pahlavan etc., Publisher: Science Press, 2003)

Notes and Handouts

Internet and Web Resources Web page for the textbook

WilliamStallings.com/Wireless1e.html Useful web sites, errata sheet, figures,

tables, slides, internet mailing list, etc. Student Support Site

WilliamStallings.com/StudentSupport.html Newsgroups

comp.std.wireless comp.dcom.*

Tentative Course Outline Week 1: Introduction of Wireless Networks

(Evolution, Promises, and Challenges) Week 2: Wireless Communication Principles Week 3: Computer Networking Basics Week 4-5: Wireless Channels and Antenna Week 6: Multiple Access Techniques Week 7: Concepts of Cellular and 1G

Systems Week 8-10: 2G Cellular Systems

Tentative Course Outline (Cont’d)

Week 11-12: 3G and Beyond Systems Week 13: Wireless LANs Week 14: Ad Hoc Networks Week 15: Mobile IP Week 16-17: Exams and Presentations

Wireless Is Hot 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

Introductions to Wireless Communications

Communication is an essential need of human being, e.g., conversation, letter

“Wireless” used to be the only (limited and unreliable) way to communicate in ancient times: 烽火狼烟、摔杯为号、铜镜反光、鸣金收兵…

Modern wireless communications are based on the electromagnetic field theory (Maxwell’s equations, Marconi’s invention)

Introductions to Wireless Communications (Cont’d)

Wireless is often prior to its wired counterpart and has become an important supplement:

Marconi’s Wireless Telegraph Wired Telegraph & Telephone Cordless, Cellular Telephone, and Wireless Local Loop

Broadcast TV Cable TV Satellite TV Aloha Network Ethernet Wireless LAN

Characteristics of Wireless Comm.

Convenience and reduced cost Service can be deployed faster than fixed

service No cost of cable plant Service is mobile, deployed almost anywhere

Unreliable channel (attenuation, fading, shadowing, interference)

Complicated design and management Device limitations (power supply, LCD) Limited bandwidth and expensive service

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?

Evolution of Wireless Systems Guglielmo Marconi invented the wireless

telegraph in 1896 Communication by encoding alphanumeric

characters in analog signal Sent telegraphic signals across the Atlantic Ocean

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

Evolution of Wireless Sys. (Cont’d)

Improved mobile telephone system (IMTS) developed in 1960 Full duplex services and direct-dialing 23 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 1947 Bell Labs began work on cellular telephone

system in the late 1960s.

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 access Shopping/banking(e-commerce) Video conferencing Video on demand Telemedicine Distance learning

Ad Hoc Networks Self-configuring mobile networks with no

infrastructure Rapid deployment and reconfiguration Robust to node failure A necessity in the battlefields of the

future? Despite much research activity, there

remain many significant technical challenges

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

What’s Your Wireless Dream?

Whoever, Whenever, Wherever, Whomever, Whatever personal communication?

Shrinking the world into earth village? Outdoor classroom on lawn under

trees? Call for help in icy storm? Browsing web on cozy seashore?