通信工程毕业设计外文翻译

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1、 附 录 一、英文原文： Goals Of True Broad bands Wireless Next Wave (4G-5G) K.R.Santhi,Prof.V.K.Srivastava,G.SenthilKumaran,Eng. Albert Butare.Kigali Institute of Science Technology and Management (KIST),B.P.3900, Kigali, Rwanda. Abstract As access technology increases, voice, video,multimedia, and broadband

2、data services are becomingintegrated into the same network. Fourth Generation (4G)is the next generation of wireless networks that will replacethird Generation (3G) networks sometimes in future. 4G isintended to provide high speed, high capacity, low cost perbit, IP based services.4G is all about an

3、 integrated, globalnetwork thats based on an open system approach. The goalof 4G is to “replace the current proliferation of core cellularnetworks with a single worldwide cellular core networkstandard based on IP for control, video, packet data andVoIP. But while 3G havent quite arrived, researchers

4、 wantto contribute their ideas to the development of an as-yetundefined wireless world that could become operationalby around 2010. This paper deals with the fundamentalsand issues of networks, technologies, spectrum, standards,terminals, services of 4G and about the visions that thenetwork operator

5、s and service providers see for theevolution of 4G mobile systems and where is future researchfrom their perspective necessary? Keywords： Wireless, 4G, W-OFDM, MC-CDMA, LAS-CDMA,UWB. I. INTRODUCTION While carriers and handset manufacturers obviously havetheir hands full with 3G, some companies are a

6、lreadylooking beyond this next generation of wirelesstechnology and networks. 4G is simply an initiative byacademic R&D labs to move beyond the limitations andproblems of 3G which is having trouble getting deployedand meeting its promised performance and throughput.While this 3G has not completely r

7、eached researchers andvendors are expressing growing interest in 4G why? Twomain areas are addressed in these initiatives: An increaseof capacity in the radio link and seamless mobility acrossheterogeneous access networks. Section 2 discusses aboutthe issues of 3G that has created interest towards 4

8、Gdevelopments. Section 3 about evolution and comparison,Section 4 describes about the goals and the vision, section5 explains about some of the technologies for 4G, and inother following sections the applications, the research andother issues for 4G developments are discussed. II. WHY THE LEAP TOWAR

9、DS 4G? 3G networks are in a very painful phase of theirdevelopment, with early trials yielding disappointingresults, costs ballooning, technical glitches, and networkoperators being forced to deflate expectations based onunrealistic hype. Despite the hype surrounding thehigher-speed 3G mobile networ

10、ks now underconstruction, the reasons for the leap towards 4G are: A. Performance Industry skeptics say that users will not be able to takeadvantage of rich multimedia content across wirelessnetworks with 3G. 4G communications will featureextremely high-quality video equal to that of high-definition

11、television. In addition, it will enable wirelessdownloads at speeds exceeding 100 Mbps, about 260times than 3G wireless network. B. Interoperability There are multiple standards for 3G making it difficult toroam and interoperate across networks. We need a globalstandard that provides global mobility

12、 and serviceportability so that service provider would no longer bebound by single-system vendors of proprietaryequipment. C. Networking 3G are based on primarily a wide-area concept. We needhybrid networks that utilize both wireless LAN (hot spot)concept and cell or base-station WAN design. With 4G

13、,the world would have base stations everywhere, ensuringphone usersconnection to a high-speed networkanywhere, anytime. D. Bandwidth We need wider bandwidth and higher bit rates. The 4Gtechnology, with its transmission speeds of more than 20mbps, would offer high-bandwidth services within thereach o

14、f LAN hotspots, installed in offices,homes,coffee shops,and airport lounges. Away from thesehotspots, customers could connect to souped-up 2Gnetworks for voice and rudimentary data coverage. E. Technology Unlike 3G, 4G will more resemble a conglomeration ofexisting technologies rather than an entire

15、ly newstandard. Analysts define 4G as a seamless combinationof existing 2G wireless networks with local-areanetworks (LANs) or Bluetooth. F. Convergence Convergence involves more than mere technology； it is acoming together of services and markets.We need allnetwork that utilizes IP in its fullest f

16、orm with convergedvoice and data capability,which the 4G will achieve. G. Cost 4G systems will prove far cheaper than 3G, since theycan be built atop existing networks and wont requireoperators to completely retool and wont require carriersto purchase costly extra spectrum.Also an open systemIP wire

17、less environment would probably further reducescosts for service providers by ushering in an era of realequipment interoperability. H. Scalability Scalability, or the ability to handle increasing numbers ofusers and diversity of services, is more challenging withmobile networks.Design for Scalabilit

18、y, includesinformation that can help you meet changing usagedemands.Because an all IP core layer of 4G is easilyscalable, it is ideally suited to meet this challenge. III.EVOLUTION AND COMPARISON OFBROADBAND WIRELESS 1) First Generation (1G):1G wireless mobilecommunication systems, was introduced in

19、 the early1980s.1G wireless was analog and supported the firstgeneration of analog cell phones.They include asignaling protocol known as SS7 (Signaling System 7). 2) Second Generation (2G): 2G systems, fielded in thelate 1980s, were intended primarily for voicetransmission and was all about digital

20、PCS. 3) Third Generation (3G): 3G in wireless will be adeliberate migration to faster, data-centric wirelessnetworks.The immediate goal is to raise transmissionspeeds from 125kbps to 2M bit/sec. 4) Fourth Generation (4G): In reality, as of first half of2002, 4G is a conceptual framework for or a discussionpoint to address future needs of a universal high speedwireless network that will interface with wirelinebackbone network seamlessly.