下一代无线宽带的目标(4G-5G)毕业论文外文翻译

1、附录 4Goals Of True Broad band s Wireless Next Wave (4G-5G)As access technology increases, voice, video multimedia, and broadband data services are becoming integrated into the same network. Fourth Generation (4G)is the next generation of wireless networks that will replace third Generation (3G) netwo

2、rks sometimes in future. 4G is intended to provide high speed, high capacity, low cost per bit, IP based services.4G is all about an integrated, global network that s based on an open system approach. The goal of 4G is to“replace the current proliferation of core cellular networks with a single worl

3、dwide cellular core network standard based on IP for control, video, packet data and Vo IP.While carriers and handset manufacturers obviously have their hands full with 3G, some companies are already looking beyond this next generation of wireless technology and networks. 4G is simply an initiative

4、by academic R&D labs to move beyond the limitations and problems of 3G which is having trouble getting deployed and meeting its promised performance and through put. While this 3G has not completely reached researchers and vendors are expressing growing interest in 4G why? Two main areas are address

5、ed in these initiatives: An increase of capacity in the radio link and seamless mobility across heterogeneous access networks.3G networks are in a very painful phase of their development, with early trials yielding disappointing results, costs ballooning, technical glitches, and network operators be

6、ing forced to deflate expectations based on unrealistic hype. Despite the hype surrounding the higher-speed 3G mobile networks now under construction, the reasons for the leap towards 4G are:A. PerformanceIndustry skeptics say that users will not be able to take advantage of rich multimedia content

7、across wireless networks with 3G. 4G communications will feature extremely 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. InteroperabilityThere are multiple standard

8、s 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. Networking3G are based on primarily a wide-area con

9、cept. 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. BandwidthWe need wider bandwidth and higher bit rates. T

10、he 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-up 2Gnetworks for voice and rudimentary dat

11、a coverage.E. TechnologyUnlike 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 Bluetooth.F. ConvergenceConvergence involves more than

12、 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. Cost4G systems will prove far cheaper than 3G, since theycan be built atop existing networks and wont require

13、operators to completely retool and wont require carrierstopurchase costly extra spectrum. Also an open systemIP wireless environment would probably further reducescosts for service providers by ushering in an era of realequipment interoperability.H. ScalabilityScalability, or the ability to handle i

14、ncreasing numbers ofusers and diversity of services, is more challenging withmobile networks.VII. ROLE OF THE WIRELESS INDUSTRYRECOMMENDATIONSWe are bringing to the attention of professionalsfollowing issues and problems that must be analyzed andresolved:1)Standardization:Standardization of wireless

15、 networksin terms of modulationtechniques, switching schemesand roaming is an absolute necessity for 4G. We mustpay more attention to general meaning advancedtechnologies.2) Lower Price Points Only Slightly Higher thanAlternatives: Thebusiness visionaries should do someeconomic modeling before they

16、start 4G hype. Theyshould understand that 4G data applications likestreaming video must compete with very low costwireline applications.3) Regulatory frameworks:Policyand RegulatoryEnvironment whichProvides Transparency, Certaintyand a Level Playing Field are necessary. The mostimportant thing is th

17、at we should recognize thatregulatory framework is as much an evolving matter astechnology, and be prepared to meet changes with anopen-minded and pragmatic attitude, always keeping theinterests of the industry and consumers in mind.4) Integration Across Different Network Topologies: Networkarchitec

18、ts must base their architecture on hybridnetwork concepts thatintegrates wireless wide areanetworks, wireless LANS (IEEE 802.11a, IEEE 802.11b,IEEE 802.11g, IEEE 802.15 and IEEE 802.16), Bluetoothwith fiber-based Internet backbone.Broadband wirelessnetworks must be a part of this integrated networka

19、rchitecture.5) Non-disruptive Implementation:Upgrading from 3G to 4G is expectedto be seamless to end-users with nodevice upgrades required.V. TECHNOLOGIES THAT SUPPORT 4GThe revolution in 4G will be the optical networking, thenew air interface, the portable device etc.A. The Transmission Protocols1

20、) OFDM: OFDM is a digital modulation technology inwhich in one time symbol waveform, thousands of orthogonal waves are multiplexed. 2) W-OFDM: W-OFDM enables data to be encoded on multiple high-speed radio frequencies concurrently. This allows for greater security, increased amounts of data being se

21、nt, and the industrys most efficient use of bandwidth. W-OFDM enables the implementation of low power multipoint RF networks that minimize interference with adjacent networks. This enables independent channels to operate within the same band allowing multipoint networks and point-to-point backbone s

22、ystems to be overlaid in the same frequency band. 3) MC-CDMA : MC-CDMA is actually OFDM with a CDMA overlay. In MC-CDMA, each user can be allocated several codes, where the data is spread in time or frequency. 4) LAS-CDMA ： Link Air Communications is developer of LAS-CDMA(Large Area Synchronized Cod

23、e Division Multiple Access) a patented4G wireless technology. LAS-CDMA enables high-speed data and increases voice capacity and latest innovative solution, CDD, merges the highly spectral efficient LAS-CDMA technology with the superior data transmission characteristics of TDD.This resulting combinat

24、ion makes CDD the most spectrally efficient, high-capacity duplexing system available today.B. The Radio Interface-UWB RadioTo make 4G really work carries will need to migrate to Ultra Wideband (UWB) technology. UWB radio will deliver essential new wireless and wired bandwidth inexpensively, without

25、 using precious and scarce radio frequencies. Instead digital video, voice and data are enabled using modulated pulses of energy that peacefullyco-exist alongside traditional communications. UWB radio solves the multipath fading issues and is 1,000% more process efficient than CDMA.C. The Network-LM

26、DSLocal multipoint distribution system (LMDS) is the broadband wireless technology used to deliver voice、 data、 Internet, and video services in the 25-GHz and higher spectrum (depending on licensing).VI. POTENTIAL APPLICATIONS OF 4G1) Virtual Presence:4G system gives mobile users a virtual presence

27、- forexample, always-on connections that keep people involved in business activities regardless of whether they are on-site or off.2)Virtual navigation: A remote database contains the graphical representation ofstreets, buildings, and physical characteristics of a large metropolis. Blocks ofthis dat

28、abaseare transmitted in rapid sequenceto avehicle, where a rendering program permits the occupantsto visualize the environment ahead.3)4)Tele-geoprocessingapplications:Thecombinationofgeographicalinformation systems (GIS),global positioning systems (GPS), and high-capacitywireless mobile systems wil

29、l enable a new type ofapplication referred to as tele-geoprocessing.5) Crisis-management applications:Naturaldisasterscan affect the entirecommunicationsinfrastructure is in disarray.Restoring communicationsquickly is essential.With wideband wireless mobilecommunications Internet and video services,

30、 could be setup in hours instead of days or even weeks required forrestoration of wireline communications.6) Education :Educational opportunities availableon the internet, for individualsinterested in life-longeducation, will be unavailable to client in remote areasbecauseof the economic unfeasibili

31、ty of providingwideband wireline internet access.4G wirelesscommunications provides a cost-effective alternative inthese situations.VIII. DEVELOPMENTS IN 4GAT&T is combining W-OFDM and EDGE technologies,to provide broadband mobile downlink access at peakrates of up to 10 Mbps while EDGE offers uplin

32、k accessat 384 Kbps with an 800KHz bandwidth in a high-mobilityenvironment. Sun Microsystems Laboratories are building 4G wirelesstechnologies that promise tointegrate voice and web datain an IP-based mobile communications. The Government of Karnataka in India has signed a MoUwith Charmed Technologi

33、es Inc from Beverly Hills,California and Software Technology Parks of India inKarnataka to develop 4G wireless technology. Theproject plan to use wireless technology based on theIEEE802.11a and IEEE802.11b standards for wirelessLAN for the underlying network is designed to support adata rate of up t

34、o 11Mbps and 54Mbps respectively. Thegoal is to get 6 billion people connected to the wirelessInternet by 2010. NTT DoCoMo and Hewlett-Packard Company &MOTOmediacollaboration will explore new mobile serviceconcepts in which people, places and things will be ableto interact, thereby bridging the real

35、 and the cyber world.MOTO-media is expected to enable high performancestreaming of multimedia content to mobile users.DoCoMo and HP aim to nish the shared study of basictechnology by 2003 and hope to push for 4G in 2006.IX. SUGGESTIONSWe would like to give the following suggestions for thedevelopmen

36、t of 4G mobile technologies: 1. Technologies like 4G must be developed to integrateinto a more flexible network that grow within thenetwork so that we dont have to scarp the old network toimplement the next generation, the generations to come. 2. The very big challenge for developing a technology is

37、proper human resource for building high quality systems.Big organization, which is engaged in software andsystem development, should rapidly go for tie-ups witheducational institutes for better manpower and knowledgemanagement.3. We talk about mobile multimedia that 4G will supportbut in reality peo

38、ple are not going to watch TV whilethey walk down the street. Likewise people will not buyCoca Cola at vending machines with a cell phone. Quitoften services conjured up by the engineering side of thevendor organizations has little to do with the reality. Sowireless industry should ponder well about

39、 marketdemand and invest money so that they will not be at loss.X.CONCLUSION4G should make a significant difference and addperceived benefit to an ordinary person lifes over 3G.We should drop the 2.5G, 3G,4G speak altogether wherean additional “ G” means merely an increase in capacity.What really me

40、ans something for the users are newservices, integration of services, applications etc. Ourgoal is tostruggle to get a “ G” eneration of standards sothat we can take our phone anywhere in the world andaccess any service or communicate with any other userany way we wantthat will offer connectivity so

41、inexpensively. In short, 4G or WWWW (World WideWireless web) should be a more intelligent technologythat interconnects the entire world without limits.译文：下一代无线宽带的目标（4G-5G）多媒体、视频、语音和宽带数据业务随着接入技术的发展增长，正在汇集到一个网络中。 4G 是下一代无线网络技术，它在不久的将来将取代第三代移动通信网络。 4G 的目标是提供高速率，高容量，每比特低消耗的网络，它是基于IP的服务。 4G 是关于所有集成，基于开放系

42、统方法的全球网络。4G 是基于IP 的控制、分组数据、视频和VoIP 标准的蜂窝网络它的目标是取代当前的的增殖核心蜂窝系统网络。手机生产商和运营商明显有他们自己应对 3G 的方法，然而一些公司已经看向下一代的无线网络和技术。 4G 是一项在实验室单纯的学术研发，其想要主动超越有关 3G 部署方面遇到的问题和麻烦局限，达到它所承诺的吞吐量和性能的问题的努力。虽然3G 还没有完全达到，但研究人员和厂商为什么对4G 越来越有兴趣？两个主要领域是解决这个问题的方法：一个是增加无线链路的容量， 另一个是异构无线接入网络的无缝移动率。3G 的发展正处于困境， 网络运营商正在被迫通过不符合实际的炒作缩小最初

43、的期望，由于初期试验带来的令人失望的结果、技术故障和成本上升。 尽管现在围绕着正在兴建中的速度更高的 3G 网络进行炒作，但朝向 4G 的跨越有几个原因：A，性能：工业怀疑论者认为，用户不能够利用多媒体资源，通过第三代无线网络。第四代通信将采用有及高品质的视频通信， 其几乎等同于高清晰度的电视。此外，它将能以100Mbps 的速度无线下载，比3G 无线网络大约快 260 倍。B，互操作性： 3G有许多标准使它很难通过网络漫游和互操作，我们需要一个全球标准来提供服务的可移植性和流动性，以至于服务提供商不再受单一系统供应商的专有设备的限制。 C，组网： 3G 主要是基于一个广域的概念，我们需要一个

44、能同时利用信元或基站广域网的设计和无线局域网的概念。在4G 技术下，世界各地将有基站，来确保手机用户能够随时随地连接到高速网络。D，宽带：我们需要更高的比特率和更宽的宽带，4G 拥有超过 20 Mbps 的传输速度，被安装在机场贵宾室、办公室、咖啡店、居民区，将以覆盖局域网内“热点 ”区域提供高带宽的服务。客户远离了这些热点，可以连接到加大马力的2G 的语音和数据网络覆盖范围。 E，技术：不像 3G 那样， 4G 将更加类似于现有技术的集合，而不是一个完全新的标准。分析家定义4G 为一个现有的 2G 网络与局域网或蓝牙无线网络的无缝结合的网络。 F，趋同性：趋同性不仅包含了单一的技术，它是未来

45、聚集在一起的服务和市场。我们需要这样能以最充分的形式利用IP 地址融合的语音和数据的能力的网络，而将实现4G 技术。 G，成本： 4G 将被证明远比 3G 便宜，因为它是建立在现有网络之上的，不需要操作者完全更新设备，运营商不需要购买昂贵的设备来拓宽频谱。此外一个开放系统的IP 无线环境可能进一步降低服务供应商的设备成本，而使我们迎来真正的互操作性时代。H，可扩展性：可扩展性， 或者说能够处理更多元化的服务和越来越多的用户，给移动网络带来了更多的挑战。无线产业建议的作用。我们将对以下问题的专业人士， 必须注意分析和解决：1）标准化：在调制技术的无线网络标准，切换方案和4G 漫游是绝对必要的。我

46、们必须重视一般意义上的先进技术。2）较低的价格仅略高于选择：商业远见者应该在他们开始4G 宣传做一些经济模型。他们应该明白，4G 数据应用如视频流必须以非常低的成本线应用竞争。世界各地的监管机构之间的频谱协调： 我们必须要求几乎免费的频谱不一定授权频谱监管机构必须参与指导研究人员表示，频段可用于 4G。3）监管框架：政策和监管环境，提供透明度，确定性和公平竞争是必要的。最重要的是，我们应该认识到，监管框架，更是一种不断发展的物质技术， 并准备迎接变化和开放、 务实的态度， 始终牢记行业和消费者的利益。 4）在不同的网络拓扑结构的集成：网络基础架构的建筑师必须在混合网络的概念，集成了无线广域网，

47、 无线局域网（ IEEE 802.11a，802.11b，802.11g IEEE，IEEE 802.15 和 IEEE 802.16），蓝牙和基于光纤的互联网骨干。宽带无线网络必须是这个整体网络架构的一部分。 5）非破坏性的实现：由 3G 向 4G 升级将是无缝的终端用户没有设备升级的要求。4G 技术： 4G 的改革将以光网络为主，便携式设备，新的空中接口等。A 传输协议。 1）频分多工： OFDM 是一种数字调制技术，它在一个时间符号波形，数千正交波形多路复用。2）正交频分多工： W-OFDM 系统使数据在多个高速无线电频率的编码同时进行。 它提供了更高的安全性， 在行业中最有效地利用带宽

48、，提高了对大量数据的发送。W-OFDM 系统可以最大限度地减少与邻近网络的干扰，能够实现多点的低功耗RF 网络。这使得我们能够拥有独立的渠道，可以把点对点骨干系统和多点网络覆盖在同一频段中。3）多载波码分多址方式：MC-CDMA系统实际上是一个包含CDMA 网络的 OFDM 网，在 MC - CDMA系统，每个用户可以分配多个代码，其中数据在时间或频率上被传播。 4）大面积同步码分多址系统：航空通信链路是大面积同步码分多址这一 4G 无线通信专利技术的开发。 LAS-CDMA 技术实现高速数据，语音容量的增加，最新创新的解决方案，客户查证 ，融合了 卓越的数 据传输特性 的高效 的时分双工 高频LAS-CDMA 技术。由此产生的结合使客户查证最频谱效率，高容量双工系统如今成为可能。 B 无线电超宽带无线接口。为了使 4G 真正进行工作，需要将载频迁移到超宽带（ UWB ）技术。超宽带无线电将为提供必要的新的有线和无线宽带带来实惠，而不需要使用珍贵和稀有的无线电频率。 相反，与传统的通信相比，数字视频、语音和数据功能的使用的能源是已存在的调制脉冲的能量。 UWB 无线电解决了多径衰落问