通信工程毕业设计外文翻译--下一代无线宽带的目标（4G—5G）

《通信工程毕业设计外文翻译--下一代无线宽带的目标（4G—5G）》由会员分享，可在线阅读，更多相关《通信工程毕业设计外文翻译--下一代无线宽带的目标（4G—5G）（18页珍藏版）》请在毕设资料网上搜索。

1、PDF外文：http:/ 5400 字  出处： Vehicular Technology Conference, 2003. VTC 2003-Fall. 2003 IEEE 58th. IEEE, 2003, 4: 2317-2321 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 Te

2、chnology and Management (KIST),B.P.3900, Kigali, Rwanda. Abstract As access technology increases, voice, video,multimedia, and broadband data services are becomingintegrated into the same network. Fourth Generation (4G)is the next generation of wireless networks that will replacethird Generation (3G

3、) networks sometimes in future. 4G isintended to provide high speed, high capacity, low cost perbit, IP based services.4G is all about an integrated, globalnetwork thats based on an open system approach. The goalof 4G is to “replace the current proliferation of core cellularnetworks with a single wo

4、rldwide cellular core networkstandard based on IP for control, video, packet data andVoIP. But while 3G havent quite arrived, researchers wantto contribute their ideas to the development of an as-yetundefined "wireless world" that could become operationalby around 2010. This paper deals wi

5、th the fundamentalsand issues of networks, technologies, spectrum, standards,terminals, services of 4G and about the visions that thenetwork operators and service providers see for theevolution of 4G mobile systems and where is future researchfrom their perspective necessary? Keywords： Wireless, 4G,

6、 W-OFDM, MC-CDMA, LAS-CDMA,UWB. I. INTRODUCTION While carriers and handset manufacturers obviously havetheir hands full with 3G, some companies are alreadylooking beyond this next generation of wirelesstechnology and networks. 4G is simply an initiative byacademic R&D labs to move beyond the lim

7、itations andproblems of 3G which is having trouble getting deployedand meeting its promised performance and throughput.While this 3G has not completely reached researchers andvendors are expressing growing interest in 4G why? Twomain areas are addressed in these initiatives: An increaseof capacity i

8、n the radio link and seamless mobility acrossheterogeneous access networks. Section 2 discusses aboutthe issues of 3G that has created interest towards 4Gdevelopments. Section 3 about evolution and comparison,Section 4 describes about the goals and the vision, section5 explains about some of the tec

9、hnologies for 4G, and inother following sections the applications, the research andother issues for 4G developments are discussed. II. WHY THE LEAP TOWARDS 4G? 3G networks are in a very painful phase of theirdevelopment, with early trials yielding disappointingresults, costs ballooning, technical gl

10、itches, and networkoperators being forced to deflate expectations based onunrealistic hype. Despite the hype surrounding thehigher-speed 3G mobile networks now underconstruction, the reasons for the leap towards 4G are: A. Performance Industry skeptics say that users will not be able to takeadvantag

11、e of rich multimedia content across wirelessnetworks with 3G. 4G communications will featureextremely high-quality video equal to that of high-definitiontelevision. In addition, it will enable wirelessdownloads at speeds exceeding 100 Mbps, about 260times than 3G wireless network. B. Interoperabilit

12、y There are multiple standards for 3G making it difficult toroam and interoperate across networks. We need a globalstandard that provides global mobility and serviceportability so that service provider would no longer bebound by single-system vendors of proprietaryequipment. C. Networking 3G are bas

13、ed 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,the world would have base stations everywhere, ensuringphone usersconnection to a high-speed networkanywhere, anytime. D. Bandwidth We need wider

14、bandwidth and higher bit rates. The 4Gtechnology, with its transmission speeds of more than 20mbps, would offer high-bandwidth services within thereach of LAN "hotspots," installed in offices,homes,coffee shops,and airport lounges. Away from thesehotspots, customers could connect to souped

15、-up 2Gnetworks for voice and rudimentary data coverage. E. Technology Unlike 3G, 4G will more resemble a conglomeration ofexisting technologies rather than an entirely newstandard. Analysts define 4G as a seamless combinationof existing 2G wireless networks with local-areanetworks (LANs) or Bluetoot

16、h. 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 form with convergedvoice and data capability,which the 4G will achieve. G. Cost 4G systems will prove far cheaper than 3G, since theycan

17、 be built atop existing networks and won't requireoperators to completely retool and won't require carriersto purchase costly extra spectrum.Also an open systemIP wireless environment would probably further reducescosts for service providers by ushering in an era of realequipment interoperab

18、ility. H. Scalability Scalability, or the ability to handle increasing numbers ofusers and diversity of services, is more challenging withmobile networks."Design for Scalability," includesinformation that can help you meet changing usagedemands.Because an all IP core layer of 4G is easilys

19、calable, 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 the early1980s.1G wireless was analog and supported the firstgeneration of analog cell phones.They include asign

20、aling 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 PCS. 3) Third Generation (3G): 3G in wireless will be adeliberate migration to faster, data-centric wirelessnetwo

21、rks.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.