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(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 services 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 offering 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 with 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 network 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 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 network capacity and user 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 King’s College 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 waves 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
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using iron filings in a glass bottle. The coherer was further 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. 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, 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 level 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 the 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Forrest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 the 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。 TWO
Personal Wireless Communication
“Mr. Watson, come here. I want to see you.\
(1) Those first words transmitted over an experimental telephone line were spoken in 1876 by Alexander Graham Bell. Bell’s 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 vibrating 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
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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 Bell’s critical patent for“ Improvements in Telegraphy\creation of the Bell Telephone System.Over the next 100 years, telephone 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 PSTN.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 concept 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 calling 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 basing 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 the 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 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.
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