无线通信原理双语lecture1

1、2022/7/201Wireless Communications Principles（bilingual course） (No:B0205061S )Lecture 1: Introduction to Wireless Communications (Mar. ,2015-Apr.2015)2022/7/202Course Information32 class hours in all13:45 - 15:20 PM, on Wedn. (4#410 room) 15:35 - 17:10 PM, on Fri. (3#305 room)Examination paper is in

2、 English.Reference books:1)Theodore S. Rappaport. Wireless Communications Principles and Practice (2nd Edition).电子工业出版社，2004年版2)Theodore S. Rappaport著， 周文安等译. 无线通信原理与应用.电子工业出版社，2006年版 3) 张业荣，竺南直，陈勇蜂窝移动通信网络规划与优化北京:电子工业出版社，2003 4) 酷哥尔. 实战无线通信应知应会新手入门，老手温故. 北京：人民邮电出版社，2010 。 Assumed knowledge: Some kno

3、wledge about communication theory and probability. Completion mode: Exam and exercises. All exams have English questions. Evaluation of the course: Exam (worth 70-80%) + Exercises (worth 30-20%)At least 5 exercises and/or homeworks must be submitted to qualify for this course.Course Information2022/

4、7/204Six Main contents in the course within 32 hours1）Introduction to Wireless Communications (ch.1,ch.2,selected ch11)2）The Cellular Concept: System Design Fundamentals(ch.3) 3）Mobile Radio Propagation: Large-Scale Path Loss(ch.4)4）Mobile Radio Propagation: Small-Scale Fading and Multipath (ch.5)5）

5、Multiple Access Techniques for Wireless Communications (ch.9)6）Wireless Networking (ch.10, selected)2022/7/2052022/7/205Six Main contents in the course within 32 hours1）Introduction to Wireless Communications (ch.1,ch.2,selected ch11) 知识点：Frequency Range in Cellular Network，Wireless Communications S

6、ystem Definitions，the Generation of Cellular Networks, Channel Capacity，signal to noise ratio(SNR), receiver sensitivity，Effects of Wireless Channels, Some Features of Wireless Channels, related abbreviation(缩略词).2022/7/206Six Main contents in the course within 32 hours2） The Cellular Concept: Syste

7、m Design Fundamentals(ch.3) 知识点： requency reuse, handoff, interference and system capacity, sectorization, cell splitting, spectral efficiency, trunking and grade of service 3）Mobile Radio Propagation: Large-Scale Path Loss(ch.4)知识点：Introduction to radio propagation: large- and small-scale effects,

8、multipath, path loss, log-normal shadowing, empirical path loss models：2022/7/2072022/7/2072022/7/207Six Main contents in the course within 32 hours4） Mobile Radio Propagation: Small-Scale Fading and Multipath (ch.5) 知识点： Small-Scale fading, time delay spread, Doppler Frequency Shift, and Doppler Fr

9、equency Spread, Parameters of Mobile Multipath Channels5）Multiple Access Techniques for Wireless Communications (ch.9)知识点：Multiple access techniques: FDMA, TDMA, CDMA, ALOHA, Slotted ALOHA, CSMA 2022/7/2082022/7/2082022/7/2082022/7/208Six Main contents in the course within 32 hours6）Wireless Network

10、ing (ch.10) 知识点：Convergence of wireless and Internet : Broadband communications，the 4G Technology, The basic network architecture of the LTE system, The physical layer transmission techniques of 4G standards(MIMO, OFDM)2022/7/209Wireless communication : the transfer of information over a distance wi

11、thout the use of electrical conductors or wires. Wireless Communication relies on radio signals, including x-rays, ultraviolet light, the visible spectrum, infrared, microwaves, and radio waves.The equation related to the speed of light：The speed of light ; carrier frequency ; wavelength ;1.1 A defi

12、nition of wireless communicationCellular Network Basics: Frequency Range2022/7/2011Cell phones operate in this frequency range, UHF = Ultra High Frequency (generally near 2GHz)Cellular Network Basics: Frequency Range2022/7/2012General Research Areas:Cellular Systems (wireless wide area networks or W

13、WANs)Satellite Systems (skip)wireless local area networks (WLANs)wireless metropolitan area networks (WMANs)Wireless Personal Area Networks(WPANs)1.2Current Wireless Systems2022/7/2013Classification of wireless networks（Referred to Kaustubh Phases, UPPSALA Uni.）2022/7/2014Emerging Research Areas and

14、 TechniquesEmerging AreasWireless Sensor Networks3.9G (LTE), 4G (LTE-a),et alKey techniques in 4G likeOFDM, and Multi-carrierMIMO(Multi-Input Multi-Output )Cognitive and Software Defined Radio, IEEE 802.22(proposed), et alCoverage(range) Area, 2022/7/2015Wireless Communications System Definitions (p

15、p:10,Table 1.4)Base Station Control channel :vital for initiating, re-questing, or paging a callForward channel: from BS to the mobile (also Subscriber)Reverse channel: from the mobile to BS Half-duplex systems allowing two-way communication by using the same radio channelFull-duplex systems allowin

16、g simultaneous two-way communication.HandoffMobile stationMSC: Mobile Switching CenterPage,RoamerSubscriber, TransceiverSimplex system and et al.2022/7/2016The big breakthrough came when AT&T Labs researchers divided wireless communications into a series of cells.High capacity with limited radio spe

17、ctrumGoal: Increase capacity while minimizinginterferenceKey : Frequency Reuse (use lower power transmitters per cell and shrinkcell size, so that frequencies can be reused more often)The Cellular Concept2022/7/2017WWANs covers a country; typically interconnecting several WMANs and providing anywher

18、e, anytime access It is useful to think of cellular Network/telephony in terms of generations: 1G: Analog cellular telephony; 2G: Digital cellular telephony ; 3G: High-speed digital cellular telephony (including video telephony); 4G First generation (1G) of cellular NetworksAnalog cellular systems(F

19、M)Only carry voice trafficLess secure and prone to interference when signal is weak Include standards such as : AMPS 30KHz FM FDMA1.3 Mobile communication networks 2022/7/2018The 2nd generation of mobile technology Or 2G Cellular NetworksGSM was the most applied technology of Cellular networksDigita

20、l cellular systems can Support high bit rate voice, limited data communicationImprove quality of service2G standards include : GSM 200KHz GMSK TDMA (was the dominant one in china) IS-95 1.25MHz , CDMA , signal bandwidth of a single channel is 1.25MHz2022/7/20193G Offers enhancements to current appli

21、cations including greater data speeds, increased capacity for voice and data and a broader range of services.In 2000, ITU approved the following three standards:cdma2000 WCDMA TD-SCDMA In addition, WIMAX (OFDM/OFDMA) was included in 2007.Highest data rate of 3G is as followingat least 144 Kb/s in a

22、vehicular environment,384 Kb/s in a pedestrian environment, 2048 Kb/s in an indoor office environment.3G (The 3rd generation wireless network) 2022/7/2020WLANs connect “local” computers (100m range)Breaks data into packetsChannel access is shared (random access)Backbone Internet provides best-effort

23、 serviceISM bands Wireless LAN Standards:Wi-Fi 802.11b,802.11a,802.11g1.4Wireless Local Area Networks (WLANs)2022/7/2021WLAN InfrastructureNetwork between devices in home and office environment;Typically gives access to a fixed infrastructure2022/7/2022802.15.1 BluetoothCable replacement RF technolo

24、gy (low cost)Short range (10m, extendable to 100m)2.4 GHz band (crowded拥挤的)1 Data (700 Kbps) and 3 voice channelsWidely supported by telecommunications, PC, and consumer electronics companiesWPANs include Bluetooth, ZigBee, Ultra-wideband (UWB), etc.802.15.3 Ultra Wideband Radio (UWB)WPANs: Wireless

25、 Personal Area Networks 1.5WPANs and WMANs 2022/7/2023Wireless Personal Area Networks (WPANs) are ad hoc networks. “removing the wire”Ad Hoc Mode may not require an access point. However all devices communicating directly with each other must use the same mode.2022/7/2024WMANsWireless Metropolitan A

26、rea Networks (WMANs)Wireless Internet connection of hotspotsHigh-speed Internet access for mobile usersDSL replacement Wireless backbone IEEE 802.16 (Broadband Wireless Access, BWA)2022/7/2025Examples ofwireless networks include wireless personal area networks (WPANs), wireless local area networks.

27、(WLANs), wireless metropolitan area networks (WMANs), and cellular networks.2022/7/20261.6 Some Features of Wireless Communications 1.6.1 Channel Capacity1)Shannons Channel Capacity TheoremThis theorem determines the theoretical limit on channel capacity for a given bandwidth(B) and signal-to-noise

28、ratio (S/N)(pp.394)2022/7/20272)Signal to Noise Ratio (SNR) & Receiver Sensitivity SNRSNR = signal power / noise powerSNR (dB) = 10*log10(signal power / noise power) Signal strength is the transmitted power multiplied by a gain impairmentsMeasure signal strength in dBW = 10*log(Power in Watts)dBm = 10*log(Power in mW)Receiver SensitivityThe received signal must have a strength that is larger than the receiver sensitivity20dB larger SNR would be good (also discussed in Lecture 2). 2022/7/202