通信论文英文翻译

论文附件一英文原文：、Introduction to Wireless Communication SystemsThe ability to communicate with people on the move has evolved remarkably since Guglielmo Marconi first radios ability to provide continuous contact with ships sailing the English channel. That was in 1897, and since then new wireless communications methods and services have been enthusiastically adopted by people throughout the world. Particularly during the past ten years, the mobile radio communications industry has grown by orders of magnitude, fueled by digital and RF circuit fabrication improvements, new large-scale circuit integration, and other miniaturization technologies which make portable radio equipment smaller, cheaper, and more reliable. Digital switching techniques have facilitated the large scale deployment of affordable, easy-to-use radio communication networks. These trends will continue at an even greater pace during the next decade.1.1 Evolution of Mobile Radio CommunicationsA brief history of the evolution of mobile communications throughout the world is useful in order to appreciate the enormous impact that cellular radio and Personal Communication Services(PCS) will have on all of us over the next several decades. It is also useful for a newcomer to the cellular radio field to understand the tremendous impact that government regulatory agencies and service competitors wield in the evolution of new wireless systems, services, and technologies. While it is not the intent of this text to deal with the techno-political aspects of cellular radio and personal communications, second-politics are a fundamental driver in the evolution of new technology and services, since radio spectrum usage is controlled by governments, not by service technology development manufacturers, entrepreneurs, or researchers. Progressive involvement in technology development is vital for a government if it hopes to keep its own country competitive in the rapidly changing field of wireless personal communications.Wireless communications is enjoying its fastest growth period in history, due to enabling technologies which permit widespread deployment. Historically, growth in the mobile communications field has come slowly, and has been couple closely to technological improvements. The ability to provide wireless communications to an entire population was not even conceived until Bell Laboratories development of cellular concept in the 1960s and 1970s Nob62, Mac79, You79. With the development of highly reliable, miniature, solid-state radio frequency hardware in the 1970s,the wireless communications era was born. The recent exponential growth in cellular technologies of the 1970s, which are mature today. The future growth of consumer-based mobile and portable communication systems will be tied more closely to radio spectrum allocations and regulatory decisions which affect or support new or extended services, as well as to consumer needs and technology advances in the signal processing, access, and network areas.The following market penetration data show how wireless communications in the consumer sector has grown in popularity. Figure 1.1 illustrates of the 20th century. Figure 1.1 is a bit misleading since the curve labeled mobile telephone does not include nontelephone mobile radio applications, such as paging, amateur radio, dispatch, citizens band(CB), public service, cordless phone, or terrestrial microwave radio systems. In fact, in 1990, licensed noncellular radio systems in the U.S. had over 12 million users,more than twice the U.S. cellular users population at that time FCC91. With the phenomenal growth of wireless subscribers in the late 1990s, combined with Nextels novel business approach of purchasing private mobile radio licenses for bundling as a nationwide commercial cellular service, todays subscriber base for cellular and Personal Communication Services(PCS) far outnumbers all noncellular licensed users. Figure 1.1 shows that the first 35 years of mobiletelephony saw little market penetration due to high cost and the technological challenges involved, but how, in the past decade, wireless communications has been accepted by consumers at rates comparable to television and the video cassette recorder.By 1934. 194 municipal police radio systems and 58 state police stations had adopted amplitude modulation(AM) mobile communication systems for public safety in the U.S. It was estimated that 5,000 radios were installed in mobiles in the mid 1930s, and vehicle ignition noise was a major problem for these early mobile uses Nob62. In 1935,Edwin Armstrong demonstrated frequency modulation(FM) for the first time, and since the late 1930s, FM has been the primary modulation technique used for mobile communication systems throughout the world. World War II accelerated the improvements of the worlds manufacturing and miniaturization and televison systems following the war. The number of U.S. mobile users climbed from several thousand in 1940 to 86,000 by 1948, 695,000 by 1958, and about 1.4 million users in 1962Nob62. The vast majority of mobile users in the 1960s were not connected to the public switched telephone network. With the boom in CB radio and cordless appliances such as garage door openers and telephones, the number of users of mobile and portable radio in 1995 was about 100 million, or 37% of the U.S. population. Research in 1991 estimated between 25 and 40 million cordless telephone were in use in the U.S.Rap91c, and this number is estimated to be over 100 million as of late 2001. The number of worldwide cellular telephone users grew from 25,000 in 1984 to about 25 million in 19993Kuc91, Goo91, ITU94, and since then subscription-based wireless services have been experiencing customer growth rates well in excess of 50% per year. As shown in Chapter 2, the worldwide subscriber base of cellular and PCS subscribers is approximately 630 million as of late 2001, compared with approximately 1 billion wired telephone line. In the first few years of 21st century, it is clear there will be an equal number of wireless andconventional wireline wireless subscriber population had already abandoned wired telephone service for home use, and had begun to rely solely on their cellular service provider for telephone access. Consumers are expected to increasingly use wireless service as their sole telephone access method in the years to come.1.2 Mobile Radiotelephony in the U.S.In 1946, the first public mobile telephone service was introduced in twenty-five major American cities. Each system used a single, high-powered transmitter and large tower in order to cover distances of over 50 km in a particular market. The early FM push-to-talk telephone systems of the late 1940s used 120 kHz of RF bandwidth in a half-duplex mode(only one person on the telephone call could talk at a time), even though the actual telephone-grade speech occupies only 3 kHz of base-band spectrum. The large RF bandwidth was used because of the difficulty in mass-producing tight mobile telephone channels per market, but with no new spectrum allocation. I,proved technology enabled the channel bandwidth to be cut in half to 60 kHz. By the mid 1960s, the FM bandwidth of voice transmissions was cut to 30 kHz. Thus, there was only a factor of four increase in spectrum efficiency due to technology advances from WW ii to the mid 1960s. Also in the 1950s and 1960s, automatic channel trunking was introduces and implemented under the label IMTS(Improved Mobile Telephone Service). With IMTS, telephone companies began offering full duplex, auto-dial, auto-trunking phone systemsCal88. However, IMTS quickly became saturated in major markets.By 1976, the Bell Mobile Phone service for the NEW York City market(a market of about 10,000,000 people at the time) had only twelve channels and could serve only 543 paying customers. There was a waiting list of over 3,700 people Cal88, and service was poor due to call blocking and usage over the few channels. IMTS is still in use in the U.S., but is very spectrally inefficient when compared to todays U.S. cellular system.二、英文翻译:无线通信系统介绍自从马可尼在英吉利海峡首先证实了无线电波能保证持续不断的与海上航 行的船只保持联系，移动通信便有了显著的发展。从1897年以后，新的无线 通信技术和服务得到了全世界的广泛认可！特别是在过去十年里，移动无线电 通信产业在数量级上的很大提高，数码和射频电路配置的一臂之力，新的大规 模的集成电路的出现，以及其他的微型技术的帮助使得便携式无线电设备更轻 巧，更便宜，更值得信赖。数字交换技术促进了无线电在能力范围内的大规模 部署，与此同时也促进了无线网络的易适用性。在未来十年里，这些趋势会以 一个一个更加稳定的趋势继续发展。1.1移动通信的发展变化为了缓解无线电和个人通信任务未来几十年将会施加在我们身上的巨大的 压力，对移动通信发展演变的简史的研究显得尤为有用。与此同时，移动通信 演变简史对于进入格状无线电领域的新来者来说也是很有用的，主要体现在它 能够使他们认识到政府管理机构和服务竞争者在无线电系统，服务以及技术上 产生了不小的冲击。虽然解决电和个人通信业务的政策问题不是这篇文章的目 的所在，但是由于射频频谱是由政府控制的，而不是由服务提供者，设备制造 商，或是企业家来控制的，所以高科技策略在新技术和新服务的发展中起着基 础性作用。如果政府想要自己的国家在快速发展的无线通信中具有竞争力那么 改革在技术发展中是必不可少。由于促成技术，无线通信经历了她快速发展的十年。但是从历史观点上来 说，移动通信领域的发展很慢，而且与科技发展紧紧相连。直到20世纪60， 70年代Nob62，Mac79，You79。随着20世纪70年代计算机硬件高依赖 性，微型性，稳定性的发展，无线通信领域诞生。无线电和个人通信系统在全 球范围上的增长对20世纪70年代新型科技做出了直接贡献，这些科技在现在 发展的愈加成熟。以消费为基础的移动通信和便携式通信系统的未来前景将会 与在光信号，数据传输，网络领域影响或支持新服务与增值业务，消费者需求， 以及科技进步的无线电光谱分配的息息相关。随后的市场调查数据显示无线通信在销售方面在大量增长。1990年，美国 注册的无线电系统已拥有超过1200万的用户，是同时期有线电用户的两倍多。 随着20世纪90年代后期无线电的显著增长，再加上纳克斯泰尔公司利用自己 的移动式收音机服务的经营许可生产无线电话产品商业的商业途径，现在的移 动电话和个人通信服务的订户数量远远超过了非移动的用户的数量。在前35年 里，移动电话由于他的成本高和技术缺陷，它的市场不是很好。但是现在，在 过去的十年里，无线通信已经像电视、广播一样被人们广泛接受。1934年，美国为了公众安全在194个市警方无线电系统以及58个州的警 察局都部署了振幅调制移动通信系统。20世纪30年代中期，据统计有5000个 无线电广播使用者，而传播媒介启动的噪声是他们这些早期使用者最大的困扰。 1935年，埃德温阿姆斯特朗第一次提出了调频这个概念。在30年代后期，调 频在世界范围上成为移动通信系统的前身。随着二战的结束，无线电有了更大 的发展。美国移动电话的使用者一路上升，从1940的几千人到1948年的86,000 到1958年的695,000到1962年14000.000人。20世纪60年代的大部分用户 没有享受到公用开关电话网络，所以他们不能直接从他们的通讯工具上接收到 消息。随着民用波段电台及无绳产品（如：车库摇控器，电话等）的繁荣，移 动电话的使用者，在1995年已达到1,000,000,000人，占美国人口的37%。1991 年的调查显示美国有250,000,000人到400,000,000人的移动电话用户，到2001 年的时候已经超过了 1,000,000,000人Pap91c。全球无线电话的用户从1984 年的 25,000 增长到 1993 年的 250,000,000Kuc91，Goo91，ITU94，而且 无线从那时起，以网络为基础的无线服务的消费者以每年50%的速度在增长。 如第二章所说的，在2001年底，与10亿人的有线电话用户相比，全球无线网 络用户只有6,300,000,000人。但是，到21世纪初，两者的数量已经持平。21 世纪初期，全球有超过1%的无线电用户不再使用家里的有线电话，仅仅使用无 线电话。预计消费者仅仅依靠无线电来通讯的时代到来了！1.2美国移动无线电话1946年，第一批公用移动电话在美国25个主要城市首先应用。为了覆盖 周围50公里的有信号的范围，每个系统采用单个、大功率的发送设备并且借助 高塔来传送信号。40年代，早期电话系统的调频一键通移动电话系统使用120 千赫带宽的半双工模式在射频（电话一次只能供一个人使用），即使是实际的电 话等级也仅仅填满3000赫兹的基础光谱。大量的无线宽带被使用是因为存在于 每个市场在铺天盖地生产小型移动电话中的困难，他们没有使用新的频谱来制 造商品。我证实高科技使宽带道通被削减到5万到6万赫兹。到60年代中期， 声音传播的调频宽带已被削减到3万赫兹。因此，频谱效能在四个方面增长的 唯一因素是二战到60年代期间高科技的发展。自动化通道的中继是在IMTS的 指示下传入和执行的。由于IMTS的帮助，电话公司可以供全双工通信制，自 动拨号，自动中继电话系统【cal88】。然而，很快IMTS在主要市场就饱和了。 1976年，纽约市场（拥有10,000,000人的市场）的彩铃移动电话业务只有12 个频道而且只能服务543个付费客户。有3700个客户在等待服务，而且由于频 道的超负荷使用，服务质量很差。虽然IMTS仍在美国使用，但是与现在美国 的移动电话系统相比，它的服务效率相当低。