Wireless Communications

Department of Electrical and Computer Engineering

Class 1

MotivationsMotivations

Recent Development– Cellular system: 3G, 4G, video, game, – WIFI everywhere– WIMAX, next generation metropolitan web for business– UWB, no cables– Bluetooth, small devices connections

Job Market – Probably one of most easy and high paid majors recently– Intel changes to wireless, Micron will follow? Cypress

Research Potential – One-to-one communication has less room to go, but

multiuser communication is still an open issue.

TextbookTextbookRequire textbook: Wireless Communications: Principles and Practice, 2nd Edition, Theodore S. Rappaport, Prentice Hall, 2001.

Wireless CommunicationsWireless CommunicationsSatellite TVCordless phoneCellular phoneWireless LAN, WIFIWireless MAN, WIMAXBluetoothUltra Wide BandWireless LaserMicrowaveGPSAd hoc/Sensor Networks

The electronics boomThe electronics boomWorld changes fast

Channel, Bandwidth, SpectrumChannel, Bandwidth, SpectrumBandwidth: the number of bits per second is proportional to B

http://www.ntia.doc.gov/osmhome/allochrt.pdf

Mobile Radio telephoneMobile Radio telephone

AMPS: advanced mobile phone system

North American Major StandardsNorth American Major StandardsPCSGSMCorelessFDMATDMACDMAModulation– FM– QPSK– GMSK– BPSK– QAM

Europe StandardsEurope StandardsGSMCT2Dect

Japan StandardsJapan Standards

Basic conceptsBasic conceptsSimplex, half-duplex, and full duplex

Frequency division duplexing, FDD– Most of system because of simplicity

Time division duplexing, TDD: – indoor system only, because of delay

Different from FDMA and TDMA

Basic concepts (cont.)Basic concepts (cont.)

Base StationBase Station

Cheaper, denser, smaller

Mobile StationMobile Station

MP3, GPS, vending machine UMPC

Pager SystemPager System

Cordless phoneCordless phoneVirtually all telephones now sold in the US use the 900 MHz, 2.4 GHz, or 5.8 GHz bands. There is no specific requirement for any particular transmission mode on 900, 2.4, and 5.8, but in practice virtually all 900 MHz phones are inexpensive, bare-bones analog models; digital features such as DSSS and FHSS are generally only available on the higher frequencies. The recently allocated 1.9 GHz band is used by the popular DECT phone standard from Europe

Cellular systemCellular systemMobile identification number (MIN) electronic serial number (ESN)Chapter 2

Land phone calls cellular phoneLand phone calls cellular phone

Cellular phone calls land phoneCellular phone calls land phone

Mobile Mobile

Base StationBase Station

HomeworkHomeworkRead Chapter 1

Questions?Questions?