4G网络技术外文翻译(共4页).doc

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1、精选优质文档-倾情为你奉上外文资料翻译Discussion on the Development Trend of Mobile CommunicationsI Introduction:Mobile communication means between the mobile users, or mobile users and fixed communications between.，With the development of electronic technology, particularly semiconductors, sets Development of circuit

2、 and computer technology and mobile communications have enjoyed rapid development. With the expansion of its application fields and on improving the performance requirements, allow mobile communication in technology and development of the theory to a higher level. Since in the 1980s of the 20th cent

3、ury, the mobile communications have become indispensable in modern communication network and one of the fastest means of communication.Reviewing the development of mobile communications, mobile communications development through several stages of development : the first major cellular mobile communi

4、cation technology of analog mobile communications, the technical characteristics of Cellular network structure overcome the regional capacity low, restricted the scope of activities of the problem. Second G is the cellular mobile communications, cellular systems can provide integrated service digita

5、l transmission, and other advantages. Main Characteristics of third G is in addition to providing second of mobile communication system own advantages, overcome its shortcomings, but can also provide broadband multimedia service can provide high - quality video multimedia integrated services, and gl

6、obal roaming. With most of them are now second technology, third technology is still not very successful. but there are already fourth technology vision. 4G standard with more than third of the fourth mobile communication system function.II. 4G about mobile communicationfourth the concept of mobile

7、communication technologies as broadband access and distribution network, with asymmetry over 2Mbits data transmission capacity. It consists of fixed broadband wireless access and broadband wireless local area network, mobile broadband system and interactive broadcasting network. fourth G standards t

8、han third standard has more functionality. In different fixed fourth g, wireless platforms and wireless services across different frequency band network, in any place with broadband Internet access, including satellite communication and stratospheric communication to provide orientation of time, dat

9、a acquisition and remote control, comprehensive functions. In addition, fourth mobile communication systems are integrated broadband mobile communication system of multifunctional are broadband IP system. Currently in development and research of 4G communications will have the following characterist

10、ics ：(A) communications fasterThe initial study on 4G communications is aimed at enhancing cellular phones and other wireless access the Internet, mobile device rate, so 4G characteristics of communication is it a faster speed of wireless communication. Experts estimated that fourth mobile communica

11、tions system up to 10 -20Mbits maximum reach 100Mbits.(B) network spectrum widthTo make 4G communication transmission speed of up to 100 Mbits, operators must be on the basis of 3G communications network to carry out large - scale improvement, so 4G network on communication bandwidth than 3G network

12、 bandwidth much higher. According to the study, each 4G channel will hold the 100 MHz spectrum, equal to 20 times of the W-CDMA3G network.(C) Complete integration of the three servicesPersonal communications, information systems, broadcasting and entertainment businesses such as seamless connection

13、as a whole, meet the various needs of users. 4G should be able to integrate different models of wireless communication to - from indoor wireless local area network and Bluetooth network, cellular signal and radio and television to satellite communication, mobile users to roam freely from a standard

14、to another standard. Business applications, interconnection between various system platform more convenient, safe, and for different users, more personalized. 4G mobile phone from the point of view of the appearance and style will have more breakthroughs can think of is, spectacles and watches, cosm

15、etic boxes, sneakers are likely to become 4G terminal.(D) intelligent properties of even higherFourth Mobile Intelligent better, not only expressed in the design and operation of 4G communication terminal with intelligent, but more importantly 4G function of cell phone can implement many unimaginabl

16、e. For example, 4G mobile phones will be based on the environment, time and other factors to timely to remind the owner of the cell phone.III, 4G access system in mobile communications4G system for mobile communication access remarkable feature is that intelligent multi - mode terminals multi-modete

17、rminal based on common platform, through a variety of technology, in various network system platform realization of seamless connection and collaboration. In 4G mobile communications, based on a common platform for all kinds of special access system, mutual cooperation, in the most optimal manner to

18、 meet the communication needs of different users. When terminal access multi - model systems, network adaptive allocation band, give the optimization of routing in order to achieve the best effect of communications.。With the development of technology and changes in market demand, new technology will

19、 constantly emerging. Different types of access technology designed for different business. therefore, the basis of our access application fields of technology, small mobile radius and working environment, and to access technology for layers. Distribution layer : mainly by the stratospheric communic

20、ations, satellite communication and broadcasting and TV communication, and the scope of service coverage. Cellular layer : mainly by 2G, 3G communication systems, services covering larger. Hot cell layer is mainly composed of WLAN network services to focus on the campus, communities, meeting center,

21、 mobile communication ability is very limited. Personal network layer : mainly used in the home, Office and other places, the service scope of coverage is very small. Mobile Communications Limited ability, but through Internet access systems of other network layer. Fixed Network : Double strands, co

22、axial cable, fiber composition of fixed communication system. Network access system in a very important position in the entire mobile networks. To improve network performance, access system of high - level agreements and Research Network self - optimization and automatic reconfiguration technology a

23、nd dynamic spectrum allocation and resource allocation technology, network management and cooperation between different access system. Improving and extending the application of IP technology in mobile network, strengthening the software radio technology and optimization of radio transmission techno

24、logies such as supporting real - time and non - real - time business, seamless connectivity and network security.IV, 4G key technology of mobile communication systemA positioning technology Positioning mobile terminal location method for measuring and calculating methods. It is mainly based on mobil

25、e terminal location, location based on mobile network location or mixed three ways. 4G mobile communication systems, mobile terminal in mobile communication between different system platforms. therefore, for mobile terminal location and tracking, is the realization of mobile terminal in seamless con

26、nections between different system platforms and systems prerequisite of high - speed and high - quality mobile communications and protection.Switch technology for mobile terminal in different mobile community between communication between different frequencies or signal to reduce channel selection,

27、and so on. Switch Technology is the future of mobile terminal in many of the communication system, mobile community between solid foundation and an important technology in mobile communications. It is mainly soft switching and hard handoff. 4G communication system, switching technique is more extens

28、ive scope, and in soft - switching and combination of hard handoff direction of development. Three software radio technology 4G mobile communication systems, software will become very complicated. To this end, The experts suggested the introduction of software radio technology, as the mobile communi

29、cations to third from second, and fourth bridges in mobile communications. Software radio technology to close as possible to the process of digital analog signal antenna, AD and DA converter soon as possible to RF Front - End using DSP channel separation, modulation and demodulation and channel deco

30、ding and so on. It aims to establish a communication platform, platform software system to realize multi - channel, multi - level and multi - mode wireless communications. Therefore, the application of software radio technology, mobile terminals can be achieved between the different systems and plat

31、forms, unimpeded. There are more mature software radio technology parameter control software radio systems. Smart Antenna with inhibition of signal interference and automatic tracking and intelligence features such as digital beam adjustment, can meet the data center, mobile IP network performance r

32、equirements. Smart Antenna beam in the space field suppression of mutual interference and to enhance the special scope of signal, this technology can improve the quality of signal increase transmission capacity. Five mutual Interference suppression and multiuser detection Development of interactive

33、Interference suppression and multiuser detection technology should become part of the 4G, they use interactive Interference suppression method introduction to the base stations and mobile phone system, elimination of unnecessary nearby and co - channel user interaction interference, to ensure the hi

34、gh quality of receiver signal reception. This combination will meet the needs of more user capacity, but also can increase the coverage. Mutual Interference suppression and multiuser detection combination of two technology will significantly reduce the deployment of network infrastructure, ensure th

35、e improvement of service quality. Signal Transmission and modulation of six new technology High - speed mobile communications, will face severe frequency selection fading frequency-selectivefading. To improve the signal performance, research and development of intelligent modulation and demodulation

36、 techniques, to effectively curb the decline. For example, the Orthogonal Frequency Division Multiplexing OFDM, adaptive equalizer. meanwhile, the TPC, Rake Spread Spectrum receive, hopping, FEC such as AQR and Turbo coding technology, to get a better signal - noise ratio of energy.V. ConclusionsNow

37、 people, 4G communication of the future looks very mysterious, Many people think that the fourth wireless communication network system is the most complex technical system in the history of mankind. All in all, smooth and comprehensively implement 4G communications, also may encounter some difficult

38、ies. first, people in the future 4G communication transmission speed of the demand was that it will greatly improve, theoretically highest reaching 100 Mbits, but the rate of mobile phones will be limited by the capacity communications systems. According to analysis by experts concerned, 4G mobile p

39、hones will be difficult to achieve the theory of speed. secondly, 4G development of the market will face great pressure. Some experts predict that, after 10 years, 2G multimedia services will enter third stage of development, which covers 3G global network has been basically completed, more than 25

40、of the world's population uses 3G, by that time, the whole industry is absorbing third technology, to accept 4G technology also needs a process of gradual transition. therefore, when the construction of 4G communication network system, carriers will consider direct 3G communications network infrastructure, with the gradual introduction of the method to make mobile communications from 3G gradual transition to 4G.专心-专注-专业