南邮研究生专业英语复习资料(8页).doc

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1、-南邮研究生专业英语复习资料-第 8 页ONE(1)The radio age began over a 100 years ago with the invention of the radiotelegraph by Guglielmo Marconi and the wireless industry is now set for rapid growth as we enter a new century and a new millennium. The rapid progress in radio technology is creating new and improved s

2、ervices at lower costs, which results in increases in air-time usage and the number of subscribers. Wireless industry revenues are currently growing between 20% and 30% per year, and these broad trends are likely to continue for several years.马可尼在100年前无线电报的发明开启了无线电时代，现在无线电行业的快速增长被认为我们进入了新世纪和新千年的时代。无

3、线技术的快速发展是以较低的成本创造新的和改进的服务，从而增加了在时间上的使用量和用户使用的数量。无线电行业的收入目前每年以20%到30%的速度增长，而这些大的趋势可能会持续几年。(2) Multiple access wireless communications is being deployed for both fixed and mobile applications. In fixed applications, the wireless networks provide voice or data for fixed subscribers. Mobile networks off

4、ering voice and data services can be divided into two classes: high mobility, to serve high speed vehicle-borne users, and low mobility, to serve pedestrian users.多址无线通信正应用于固定和移动设备。在固定应用中，无线网络为固定用户提供了语音、数据业务。移动网络提供的语音、数据业务被分为两类：高速移动性，为高速车载用户服务；低移动性，为行人用户服务。(3) Wireless system designers are faced wit

5、h a number of challenges. These include the limited availability of the radio frequency spectrum and a complex time-varying wireless environment (fading and multipath). In addition, meeting the increasing demand for higher data rates, better quality of service (QoS), fewer dropped calls, higher netw

6、ork capacity and user coverage calls for innovative techniques that improve spectral efficiency and link reliability.无线系统的设计人员面临着一系列挑战。无线系统的设计人员面临着一系列挑战。此外，满足更高的数据速率的需求日益增加，更好的服务质量（服务质量），更少的掉线问题，以及较高的网络容量和用户覆盖要求创新的技术，这些创新技术能要提高频谱效率和链路可靠性。(4) Wireless system designers are faced with a number of chall

7、enges. These include the limited availability of the radio frequency spectrum and a complex time-varying wireless environment (fading and multipath). In addition, meeting the increasing demand for higher data rates, better quality of service (QoS), fewer dropped calls, higher network capacity and us

8、er coverage calls for innovative techniques that improve spectral efficiency and link reliability.无线系统设计人员面临着许多挑战，这些挑战包括无线电频谱的有限可用性和复杂的时变无线环境（衰落及多径）。此外，需要更好的服务质量，更少的掉线，更高的网络容量和改善频谱效率和链路可靠性创新技术来提升网络容量和用户的覆盖来满足越来越高的数据速率的需求。(5) The origins of radio date back to 1861 when Maxwell, while at Kings College

9、 in London, proposed a mathematical theory of electromagnetic (EM) waves. A practical demonstration of the existence of such waves was performed by Hertz in 1887 at the University of Karlsruhe, using stationary (standing) waves. Following this, improvements in the generation and reception of EM wave

10、s were pursued by many researchers in Europe.广播是一种电磁波的数学理论，它的起源可以追溯到麦斯威尔在伦敦国王学院的1861年。1887年，赫兹使用固定（站立）波在卡尔斯鲁厄大学切实可行的证明了这种波。在此之后，许多欧洲的研究人员继续改进电磁波的产生和接收。(6) In 1890, Branly in Paris developed a “coherer” that could detect the presence of EM waves using iron filings in a glass bottle. The coherer was f

11、urther refined by Righi at the University of Bologna and Lodge in England. Other contributions came from Popov in Russia, who is credited with devising the first radio antenna during his attempts to detect EM radiation from lightning.1890年，巴黎的Branly开发出一种“检波器”，该检波器可以通过玻璃瓶中的铁屑检测出电磁波的存在。这种检波器后来被博洛尼亚大学的

12、Righi和英国的Lodge进一步改善。检波器其他方面的改进还源于俄罗斯的Popov，Popov曾在试图从闪电中检测电磁辐射的时候发明了第一个无线电天线。(7) In 1890, Branly in Paris developed a “coherer” that could detect the presence of EM waves using iron filings in a glass bottle. The coherer was further refined by Righi at the University of Bologna and Lodge in England.

13、 Other contributions came from Popov in Russia, who is credited with devising the first radio antenna during his attempts to detect EM radiation from lightning.1980年，通过使用装有铁屑的玻璃瓶，巴黎的Branly发明了一种能够检测EM波的检波器。该检波器被博洛尼亚大学的Righi和英国的Lodge进一步改善。俄罗斯的波波夫做出了其他的贡献，波波夫在试图从雷电中检测出EM辐射的尝试中，发明了第一个无线天线。(8) That year,

14、 his signal bridged the English Channel, 52 km wide, between Wimereux and Dover. His other technical developments around this time included the magnetic detector, which was an improvement over the less efficient coherer, the rotatory spark and the use of directive antennas to increase the signal lev

15、el and to reduce interference in duplex receiver circuits.在那一年， 他的这个信号穿越了英吉利这个位于维姆勒和多佛之间，宽52公里的海峡。而在这个时期，他的其他技术发明还包括：能用于改善检波器效率低的磁探测器，在双重接收器电路中，使用旋转火花和定向天线来提高信号电平，减少干涉。(9) In the next few years, Marconi integrated many new technologies into his increasingly sophisticated radio equipment, including t

16、he diode valve developed by Fleming, the crystal detector, continuous wave (CW) transmission developed by Poulsen, Fessenden and Alexanderson, and the triode valve or audio developed by Forrest.在未来几年内,马可尼集成许多新技术日益复杂的无线电设备,包括由Fleming发明的二极管阀, 由Poulsen,Fessenden 和Alexanderson发明的晶体检波器,连续波(CW)传输, 以及由Forr

17、est发明的三极管阀或音频。(10) Civilian use of wireless technology began with the installation of the first 2 MHz land mobile radiotelephone system in 1921 by the Detroit Police Department for police car dispatch. The advantages of mobile communications were quickly realized, but its wider use was limited by th

18、e lack of channels in the low frequency band. Gradually, higher frequency bands were used, opening up the use of more channels.民用无线技术中的2 MHz的陆地移动无线电话系统警在1921被底特律公安部门用于警车调度。移动通信的优点是快速实现，但其更广泛的使用是有限的，低频率的信道的缺乏限制了它的使用。渐渐地，使用了更高的频段，开启了更多的通道。TWOPersonal Wireless Communication“Mr. Watson, come here. I wan

19、t to see you.(1) Those first words transmitted over an experimental telephone line were spoken in 1876 by Alexander Graham Bell. Bells liquid variable resistance transmitter was based on the principal that the human voice could be telegraphed using the vibrations of a permanent magnet to induce a vi

20、brating current in the coils of an electromagnet. 通过实验电话线传输的第一句话是说在1876年亚历山大格雷厄姆贝尔。贝尔的液体可变电阻传感器是基于主要的人类的声音可以主张使用永久磁铁的振动诱导振动电流电磁铁的线圈。(2) Eventually this invention and Bells critical patent for“ Improvements in Telegraphy led to the creation of the Bell Telephone System. Over the next 100 years, telep

21、hone networks were constructed across the world with millions of miles of copper wire connecting telephone subscribers to the traditional wire line circuit switched network referred to as the Public Switched Telephone Network (PSTN)。最后这个发明和Bell的“电报完善“的决定性专利引导了Bell电话系统的创建。在之后的100年，电话网络通过成百上千万英里的连接电话用

22、户的铜线,说的话到传统线路转变正如公共转换电话网络的参考网络来构建的。(3) Remarkably, the local-access part of this network has remained relatively unchanged. It requires a twisted copper pair from the serving wire center to the subscriber location. Telecommunications users had to use telephone devices that were hard-wired to the PST

23、N. This requirement was not acceptable to many users who needed mobility, particularly businesspeople needing to stay in touch with a home office.值得注意的是，本地接入部分的网络保持相对不变。它需要一个从发球线中心到用户位置的双绞线铜线。电信用户使用的电话设备，是硬连接到PSTN网络的。这一要求是不能被许多有很强流动性的用户所接受的，特别是需要与一个家庭办公室保持联系的商务人士。(4) Personal communications is the c

24、oncept of anytime, anywhere, anyhow seamless communications. Personal communications users have a mobile device or mobile station (MS) that not only allows them to communicate with clear voice quality but to read and compose text messages, and access a common set of service features like three-way c

25、alling no matter where they are. Furthermore, calls in progress are not interrupted when travelling between service areas. In short, wireless personal communications systems provide full mobility. 个人通信是随时随地的，保持无缝通信的概念。个人通信用户有一个移动设备或者移动台，不仅使他们能够以清晰的语音质量进行通信，而且还能阅读和撰写短信，并且无论在哪里都能访问一套共同的服务功能，如三方通话。此外，保

26、证服务器之间移动时正在进行的呼叫不被中断。总之，无线个人通信系统提供了充分的移动性。(5) Personal communications services also include a number of advanced data services. Users are able to send and receive text messages, read electronic mail, and access the World Wide Web. Wireless service providers are beginning to enhance features by basin

27、g them on the location of the mobile subscriber and by accessing network databases that provide additional call routing intelligence. Pursuant to a Federal Communications Commission (FCC) mandate for improved emergency call response, the location of a mobile emergency 911 caller can be provided to t

28、he nearest 125 m at least 67% of the time. 个人通信服务还包括一些高级数据服务。用户可以收发短信，读电子邮件，并访问互联网。无线服务供应商开始根据用户手机的位置和提供额外的智能呼叫选路连接网络数据库来加强功能。依照FCC提高紧急呼叫响应的命令，拨打紧急热线911的电话的位置大概有67%的能被精确到125m范围。(6) Furthermore, industry experts predict that intelligent network control functions based on location, dialed digits, time

29、 of day, and so on will soon be commonplace. The benefits of mobile communication over wired communications are creating a world where a personal communicator can be a viable substitute for a traditional landline telephone as the primary means of communication.此外，业内专家预测，基于位置、所拨号码以及时间段等因素的智能网络控制功能将很快

30、得到普及。移动通信较有线通信的优势在于创造了一个个人通信设备有效替代传统固定电话成为主要通讯手段的世界。GSM Today(7) The Global System for Mobile Communications (GSM) is an international digital cellular telecommunications standard. The GSM standard was released by ETSI (European Standard and Technology Institute) in 1989. First commercial services w

31、ere launched in 1991. After its early introduction in Europe the standard went global in 1992 with GSM services introduced in Australia. Since GSM has become the most widely adopted and fastest-growing digital cellular standard, it positioned to become the worlds dominant cellular standard.全球移动通信系统(

32、GSM)是一个国际数字蜂窝通信标准。1989年ETSI发布了此标准(欧洲电信标准化协会)。第一次商业服务于1991年推出。1992年当GSM服务被推广到澳大利亚后，GSM成为了全球化的标准。既然GSM是发展最快和被最广泛采用的数字蜂窝标准,它成为世界上最主要的蜂窝标准。(8) GSM is the foundation for the Digital Cellular System 1800 (DCS 1800), and the Personal Communications System 1900 (PCS 1900). GSM 900 is the original system tha

33、t was first implemented in Europe in the early to mid-1980s. DCS 1800 is an upbanded version of GSM 900. PCS 1900 is also based on GSM and is the North American version. It is quite similar to GSM, with only minor differences. In 1997, DCS 1800 was renamed GSM 1800.GSM是数字蜂窝系统1800（DCS 1800）和1900个人通信系

34、统（DCS 1900）。GSM 900 是最原始的系统，它首次发展是在欧洲1980年代中期。DCS1800 是GSM的upbanded版本。PCS 1900也是基于基于GSM，它是北美的版本。它和GSM非常相似，只有细微的差别，1997年，DCS 1800改名为GSM 1800。(9) A variety of data services built into the GSM standard allow the user to directly access fax, data and in the future even Internet services. Short message s

35、ervices enable the user of a GSM phone to combine traditional cellular voice services with paging services in a single unit. GSM has been defined as a platform, which is adaptable to a variety of new market requirements. This will enable the user to utilize a maximum of personal communication a must

36、 for the modern cellular subscriber.嵌入GSM标准的各种数据服务允许用户直接访问传真、数据,甚至在未来互联网服务。GSM的短消息服务允许用户电话结合传统蜂窝语音服务与分页服务在一个单一的单位。GSM被定义作为一个平台,适应各种新的市场需求。这将使得用户使用最多的个人通信,必须为现代手机用户。(10) Compared to older cellular transmission standards GSM includes a variety of network access, voice, and data services. Features like

37、 seamless roaming and handover provide a maximum level of flexibility to the user while being on the move. GSM for the first time enabled users to access personal communication services anytime, anywhere.相比老蜂窝传输标准GSM包括多种网络接入，语音和数据服务。如无缝漫游和切换的功能，同时提供了最大程度的灵活性，用户在移动。GSM首次启用用户访问个人通信服务在任何时间，任何地方。THREE(1

38、)4Gs predecessor, 3G wireless, is still taking off. The fourth-largest wireless-service provider, T- Mobile, launched its 3G network this year. So if 3G is just getting going, what does that mean for 4G? Opinions on when 4G services might be available differ. Unlike 3G, no specific standards spell o

39、ut what a 4G service, network or technology is today. 4G的前身-3G无线，目前仍然飞速发展。今年第四大无线服务提供商T移动，推出了其3G网络。那么如果说3G才刚刚起步，4G意味着什么？关于4G可用的服务方面人们的意见各不不同。不同于3G，指出的是今天的网络技术-4G服务没有具体的标准。(2)Analysts say these specifications are to come, but today 4G is more of a marketing idea, says Phil Redman, a research vice pre

40、sident at Gartner. The Next Generation Mobile Networks (NGMN) group says commercial services beyond 3G could launch as early as 2010. KPN Mobile, Orange, Sprint, T-Mobile International, Vodafone, China Mobile and NTT DoCoMo make up NGMN. The goal of the group, similar to the WWRF, is to work with st

41、andards bodies in developing next-generation specifications. But if standards dont come before 2015, as Gartner Redman predicts, true 4G services could come only after 2015.分析师认为，标准就要出台了。但是Gartner副总裁Phil Redman认为，今天4G更多的是一个营销理念。下一代移动通信网络组织(该组织由Orange, Sprint, T-Mobile International, Vodafone, China

42、Mobile and NTT DoCoMo组成 )认为超越3G的商业服务网络最早将在2010年面市。这个组织的 目标与WWRF相似，为下一代网络制定标准体系。但是Gartner Redman 预言，如果这项标准没有在2015年出台，真正的4G服务将推迟到2015年之后。(3)Answering this question is not a simple task. It depends on who (manufacturers, operators, academia, regulatory bodies, users) and when (this is being written in

43、June 2005) you ask. Moreover, answers might not depict a wholly homogeneous view, even within parties belonging to the same group. Fortunately, when trying to define 4G, one can find a number of similar visions that are shared by several of the forces behind 4G. This encourages us to think that a gl

44、obal common understanding of 4G can be attained. To show both the diversity and commonality of viewpoints on 4G, a few answers to the above question are shown.要回答这个问题并不是一个简单的事情。它取决于是谁（制造商、运营商、学术机构、管理机构、用户）在什么时候（这篇文章写于2005年6月）来问这个问题。而且，即使是在同一组的内部，可能都无法给出一个反映一致观点的答案。幸运的是，当试图定义4G，可以找到一些类似的景象，这些景象是几个背后的

45、力量共享4G的。这鼓励我们认为对全球4G的共识是可以实现的。展示的多样性、和4G的通用性，给出了对上述问题的一些答案。(4)1Unlike 3G, which refers to a specific mobile standard and allows the transfer of data at a minimum accepted speed, 4G, or the fourth generation of wireless communications, refers to a collection of technologies and standards that will fi

46、nd their way into a range of new ubiquitous computing and connections systems. In its earliest stages, 4G offers the promise of allowing users to connect to the Internet and one another through a variety of devices and standards anytime, anywhere, and at a wide range of speeds, from narrowband to br

47、oadband.3G标准是一种特定的移动通信标准，其允许数据以一个最小可接受的速率进行传输，然而，4G与3G不同，4G（第四代无线通信标准）是指选择一些技术和标准，这些技术和标准适用于一系列新的泛在的计算和连接系统。在最早期的阶段，4G提供允许用户随时随地，从窄带到宽带的一个速度范围内通过各种设备和标准连接到互联网。(5)24G is defined as mobile telephony at data rates of 100 Mbit/s globally; that is, between any two points in the world. Locally, 1 Gbit/s w

48、ill be possible.3The main characteristics of the next generation of mobile systems are : (1)A new air interface aiming for 50 to 100 Mbit/s deployable in 2010. (This is what defines 4G.) . (2) The integration of existing system to interwork with each other and with the new interface. (This is what d

49、efines system beyond 3G.)4G是一种移动电话系统，该系统在全球范围内（即在世界的任意两点之间）可以实现100Mbit/s的数据速率，在本地范围内，有可能可以达到1Gbit/s的速率。下一代移动通信系统的主要特点是：（1）在2010年针对可展开的50-100M/s的新的空中接口（这就是4G的定义）；（2）通过相互作用和新的界面对现有的系统进行集成（这就是超过3G的系统的定义）(6)4The European vision for a fourth generation terrestrial system is a fully IP-based integrated system offering any kind of services at any time and able to support multi