无线通信基础(双语)_教学课件_1.ppt

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1、WiredWirelessEach cable is a different channelOne media shared by allSignal attenuation is lowHigh signal attenuationLow interference(Cross-talk)High interference noise co-channel interference adjacent channel interferencel How does signal propagate?l How much attenuation take place?l How does signa

2、l look like at the receiver?l How does signals using the same propag-ation channel?TxRxProvide comprehensive understanding of fundamental principles underlying wireless communications and networkingPrinciples include:l Characteristics and performance limits of wireless systemsl Techniques to overcom

3、e the difficultiesIntroduction to main topics2Course information3 1Overview of wireless communications3 3Introduction to main topics2Course information3 1Overview of wireless communications3 3Email:jiangzhugfkd.mtn Phone:74477 13787179473Office:103 room,4th Departments General Buildingl Text Wireles

4、s Communications and Networking by Jon W.Mark and Weihua Zhuangl Reference Modern Wireless Communications by Simon Haykin and Michael Moherl Lecture Notes by Dr.Jiang Zhul Some basic knowledge of communicationl Some basic knowledge of signals and systemsl Some basic knowledge of probability and stat

5、isticsl Class Time:18 Lectures(36 credit hours)l Labs:4 credit hours l Final exam:?l Experiment 15%l Homeworks&Class Participation 5%l Final Exam 80%Introduction to main topics2Course information3 1Overview of wireless communications3 3Overview of Wireless Communications3 11.1 Definition of Wireless

6、 communication1.2 Historical overview of wireless communication1.3 Types of wireless communications1.4 The development of wireless communicationCharacterization of the Wireless Channel3 22.1 Radio propagation environment2.2 Linear time-variant channel model2.3 Channel correlation functions2.4 Large-

7、scale path loss and shadowing2.5 Small-scale multipath fadingBandpass transmission Techniques for Mobile Radio3 33.1 Introduction3.2 Digital Modulation3.3 Probability of Transmission Error3.4 Spread SpectrumFundamentals of Cellular Communications3 44.1 Introduction4.2 Frequency reuse and mobility ma

8、nagement4.3 Cell cluster concept4.4 Cochannel and adjacent channel interference4.5 Call blocking and delay at the cell-site4.6 Other mechanisms for capacity increase4.7 Channel assignment strategiesMultiple Access Techniques3 55.1 Multiple access in a radio cell5.3 Conflict-free multiple access tech

9、nologies5.4 Spectral efficiency5.2 Random AccessIntroduction to main topics2Course information3 1Overview of wireless communications3 3Overview of Wireless Communications3 11.1 Definition of Wireless communication1.2 Historical overview of wireless communication1.3 Types of wireless communications1.

10、4 The development of wireless communicationl Transmitting voice and data using electromagnetic waves in open spacel Electromagnetic waves Travel at speed of light(c=3x108 m/s)Has a frequency(f)and wavelength(l l)c=f l l Propagation characteristics are different in each frequency band UV1 MHz1 kHz1 G

11、Hz1 THz1 PHz1 EHzinfrared visibleX raysGamma raysAM radioS/W radioFM radioTVTVcellularLFHFVHFUHFSHFEHFMF 30kHz300kHz3MHz30MHz300MHz30GHz300GHz10km1km100m10m1m10cm1cm100mm3GHz902 928 Mhz2.4 2.4835 Ghz5.725 5.785 GhzISM bandionosphereGround WaveSky waveSpace waveRelaySat.RelayhRdClassification BandIni

12、tialsFrequency RangeCharacteristicsExtremely lowELF 300 HzGround waveInfra lowILF300 Hz-3 kHzVery lowVLF3 kHz-30 kHzLowLF30 kHz-300 kHzMediumMF300 kHz-3 MHzGround/Sky waveHighHF3 MHz-30 MHzSky waveVery highVHF30 MHz-300 MHzSpace waveUltra highUHF300 MHz-3 GHzSuper highSHF3 GHz-30 GHzExtremely highEH

13、F30 GHz-300 GHzTremendously highTHF300 GHz-3000 GHzl Provides mobilityA user can send or receive a message no matter where he or she is locatedl Added convenience/reduced costEnables communication without installing an expensive infrastructurel The wireless channell Wireless channels are a difficult

14、 and capacity limited broadcast communications mediuml Modulation、coding、equalization、diversity etc.l User mobilityl Traffic patterns,user locations,and network conditions are constantly changingl Handoff and Location managementThe fundamental physical resource in wireless systems is the radio spect

15、rum.The development of wireless communications has often a search for more efficient ways of using the radio spectrum.This layer provides the physical mechanism for transmitting bits between any pair of nodes.One purpose of the data-link layer is to perform error correction of detection,this layer i

16、s also responsible for the way in which different users share the transmission medium.This layer has several functions,one of which is to determine the routing of the information.A second function is flow control,to ensure that the network does not become congested.1864-Maxwell predicts existence of

17、 electro-magnetic (EM)waves 1887-Hertz proves existence of EM waves;first spark transmitter generates a spark in a receiver several meters away 1890-Branly develops coherer for detecting radio waves 1896-Marconi demonstrates wireless telegraph to English telegraph office 1897-Marconi awarded patent

18、for wireless telegraph1897-First“Marconi station”established on Needles island to communicate with English coast 1898-Marconi awarded English patent for tuned communication 1898-Wireless telegraphic connection between England and France established1901-Marconi successfully transmits radio signal acr

19、oss Atlantic Ocean from Cornwall to Newfoundland1902-First bidirectional communication across Atlantic 1909-Marconi awarded Nobel prize for physics 1914-First voice over radio transmission1924-Bell Laboratories claim the first mobile 2-way voice based radio telephone1920s-Mobile receivers installed

20、in police cars in Detroit1930s-Mobile transmitters developed;radio equipment occupied most of police car trunk1935-Frequency modulation(FM)demonstrated by Armstrong1946-First interconnection of mobile users to public switched telephone network(PSTN)1947-(at Bell Labs)D.H.Ring described the cellular

21、network idea in an internal memo.1969-The Bell System made commercial cellular radio operational by employing frequency reuse for the first time.1976-Bell Mobile Phone has 543 pay customers using 12 channels in the New York City area;waiting list is 3700 people;service is poor due to blocking1979-NT

22、T/Japan deploys first cellular communi-cation system1983-Advanced Mobile Phone System(AMPS)deployed in US in 900 MHz band1989-Groupe Spcial Mobile defines European digital cellular standard1991-US Digital Cellular phone system introduc-ed 1993-IS-95(CDMA)digital cellular system depl-oyed in US1995-F

23、CC auctions off frequencies in Personal Communications System(PCS)band at 1.8 GHz for mobile telephony,The auction money for six broadband PCS licensed bands(120 MHz)almost reaches 20 billion US dollars1999-ITU decides the next generation mobile com-munication systems(e.g.,W-CDMA,cdma2000,etc)2000s

24、Third/fourth generation cellular system standards,Bluetooth,WiFi,ad hoc networks,sensor networksFirst GenerationAnalogueCircuit switchedBasic voice telephonyLow capacityLimited local and regional coverageSecond GenerationDigitalCircuit switchedVoice plus basic data applicationsLow data speedEnhancem

25、ents towardspacket switchinghigher data ratesTrans-national and global roamingDigitalPacket and circuit switchedAdvanced data(multimedia)applicationsFast data accessGlobal coverageGlobal roamingThird GenerationBeyond ThirdGenerationDigitalPacket switchedAll IP based(IPv6)More advanced multimedia app

26、licationsUser in controlFlexible platform of complementary access systemsHigh speed dataImproved QoSGlobal coverageGlobal roaming Over 80%of worlds population has cellular coverage Over 3 billion cellular subscribersl Half of the worlds population Many developed countries have more subscribers than

27、peopleCellular has enjoyed exponential growth since 1988 Ignited the recent wireless revolution Asia way ahead of the rest of the worldMuch hype in 1990s,great failures around 2000q Mobile Cellular Networksq Wireless Data Networksq Mobile Satellite Communicationq Ad Hoc Networks q Wireless Sensor Ne

28、tworks q GPSq Cordless Phoneq Paging SystemWhat is a cellular system?FCC defines the cellular system as:l A system in which assigned radio spectrum is divided into discrete channels,which are assigned in groups to geographic cells covering a cellular geographic service area.l A system which uses rad

29、io transmission rather than physical wire lines to provide telephone service.Cellular System Characterized bylHigh mobility provisionlWide-rangelTwo-way voice communicationlHandoff and roaming supportlIntegrated with sophisticated public switched telephone network(PSTN)lHigh transmit power requires

30、at the handsets(2W)Wi-Fi short for Wireless Fidelity,is a set of standards for WLAN currently based on the IEEE 802.11specifications.WLAN using the IEEE 802.11HiperLAN is a European StandardWireless LANInternetAccessPointWireless LANWireless LANWireless Personal Area Network(WPAN)IEEE 802.15.1 Bluet

31、oothIEEE 802.15.3 UWBIEEE 802.15.4 ZigBee RadiosWireless PANWireless PANBluetoothCover very large areasOptimized for one-way transmissionRadio(DAB)and movie(SatTV)broadcastingMost two-way systems struggling or bankruptExpensive alternative to terrestrial systemPeer-to-peer communications.No backbone

32、 infrastructure.Routing can be multihop.Topology is dynamic.Single Hop(Cellular)BaseBaseBaseBaseMulti-Hop(Ad Hoc)Base stationAntennaSensorTargetWLANWLANWPANWPAN2G2G3G3GMbpsMbps10010010101 10.10.1MobilityMobilityININOUTOUTFIXEDFIXEDWALKWALKFIXEDFIXEDWALKWALKVehicleVehicleWireless Internet accessN-th

33、generation CellularWireless Ad Hoc NetworksSensor Networks Wireless EntertainmentSmart Homes/SpacesAutomated HighwaysAll this and moreUbiquitous Communication Among People and DevicesHard Delay ConstraintsHard Energy ConstraintsInternetPSTN(Telephone Network)Mobile Users-Cell phone users-Cordless ph

34、one usersMobile Users-Laptop users-Pocket PC users-Mobile IPWireless AccessTelecom People ViewData Networking People ViewTelecom and Data Networking-Radio Propagation-Link Characteristics-Error Models-Wireless MediumAccess(MAC)-Error Control-Data Transmission-Mobile IP(integrating mobile hosts to in

35、ternet)-Ad-hoc Networks-TCP over Wireless-Service Discovery-Voice Transmission-Frequency Reuse-Handoff Management-Location Tracking-Roaming-QoS-GSM,CDMA,Cordless Phones,-GPRS,EDGETelecom InterestData Networking InterestJTRSl Course outlinel Overview of wireless communications Some history A positive view of the future of wireless communicationsl Why does FM signal offer better receptive quality compared with AM signal in wireless communication system?