浅谈关于移动通信发展趋势毕业论文外文翻译

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1、Talk about the development trend for mobile communicationsOne， 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 and computer tech

2、nology 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 century, the mobile co

3、mmunications 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 communication technology

4、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 digital transmission, an

5、d 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 global roaming. With

6、 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.。Two. 4G about mobile cfourth the concept of mobile communication technologies a

7、s 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 than third standard has more

8、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, data acquisition and remote con

9、trol, 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 characteristics ：ommunications A communi

10、cations 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 communications system up

11、to 10 -20Mbits maximum reach 100Mbits. The second 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 bandwid

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

13、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 to another s

14、tandard. 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, cosmetic boxes,

15、sneakers are likely to become 4G terminal.Four 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 unimaginable. For exam

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

17、sed 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 meet the

18、 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 constant

19、ly 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 communications, s

20、atellite 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, mobile c

21、ommunication 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, coaxial cab

22、le, 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 and dynami

23、c 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 technologies su

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

25、nal 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 connection

26、s between different system platforms and systems prerequisite of high - speed and high - quality mobile communications and protection.The second handover technology Switch technology for mobile terminal in different mobile community between communication between different frequencies or signal to re

27、duce channel selection, 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, switchin

28、g technique is more extensive 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 technol

29、ogy, as the mobile communications 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 dem

30、odulation and channel decoding 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, a mobile terminals can be achieved between th

31、e different systems and platforms, unimpeded. There are more mature software radio technology parameter control software radio system. Four smart antenna technology Smart Antenna with inhibition of signal interference and automatic tracking and intelligence features such as digital beam adjustment,

32、can meet the data center, mobile IP network performance requirements. 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 suppre

33、ssion and multiuser detection Development of interactive 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

34、- channel user interaction interference, to ensure the high 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 r

35、educe the deployment of network infrastructure, ensure the 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 a

36、nd development of intelligent modulation and demodulation 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

37、a better signal - noise ratio of energy.Five. conclusions Now 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 i

38、mplement 4G communications, also may encounter some difficulties. 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 sys

39、tems. According to analysis by experts concerned, 4G mobile phones 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

40、3G global network has been basically completed, more than 25 of the worlds 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, carr

41、iers will consider direct 3G communications network infrastructure, with the gradual introduction of the method to make mobile communications from 3G gradual transition to 4G.浅谈关于移动通信发展趋势一、 引言 移动通信是指移动用户之间，或移动用户与固定用户之间的通信。移动通信是指移动用户之间，或移动用户与固定用户之间的通信。随着电子技术的发展，特别是半导体、集 成电路和计算机技术的发展，移动通信得到了迅速的发展。随着其应

42、用领域的扩大和对性能要求的提高，促使移动通信在技术上和理论上向更高水平发展。20世纪80年代以来，移动通信已成为现代通信网中不可缺少并发展最快的通信方式之一。回顾移动通信的发展历程，移动通信的发展大致经历了几个发展阶段：第一代移动通信技术主要指蜂窝式模拟移动通信，技术特征是蜂窝网络结构克服了大区制容量低、活动范围受限的问题。第二代移动通信是蜂窝数字移动通信，使蜂窝系统具有数字传输所能提供的综合业务等种种优点。第三代移动通信的主要特征是除了能提供第二代移动通信系统所拥有的各种优点，克服了其缺点外，还能够提供宽带多媒体业务，能提供高质量的视频宽带多媒体综合业务，并能实现全球漫游。现在用的大多是第二

43、代技术，第三代技术还不太成功，但已有了第四代技术的设想。第四代移动通信系统（4G）标准比第三代具有更多的功能。二、4G移动通信简介第四代移动通信技术的概念可称为宽带接入和分布网络，具有非对称的超过2Mbit/s的数据传输能力。它包括宽带无线固定接入、宽带无线局域网、移动宽带系统和交互式广播网络。第四代移动通信标准比第三代标准拥有更多的功能。第四代移动通信可以在不同的固定、无线平台和跨越不同的频带的网络中提供无线服务，可以在任何地方用宽带接入互联网（包括卫星通信和平流层通信），能够提供定位定时、数据采集、远程控制等综合功能。此外，第四代移动通信系统是集成多功能的宽带移动通信系统，是宽带接入IP系

44、统。目前正在开发和研制中的4G通信将具有以下特征：（一）通信速度更快由于人们研究4G通信的最初目的就是提高蜂窝电话和其他移动装置无线访问Internet的速率，因此4G通信的特征莫过于它具有更快的无线通信速度。专家预估，第四代移动通信系统的速度可达到10-20Mbit/s，最高可以达到100Mbit/s。（二）网络频谱更宽要想使4G通信达到100Mbit/s的传输速度，通信运营商必须在3G通信网络的基础上对其进行大幅度的改造，以便使4G网络在通信带宽上比3G网络的带宽高出许多。据研究，每个4G信道将占有100MHz的频谱，相当于W-CDMA3G网络的20倍。（三）多种业务的完整融合个人通信、信

45、息系统、广播、娱乐等业务无缝连接为一个整体，满足用户的各种需求。4G应能集成不同模式的无线通信从无线局域网和蓝牙等室内网络、蜂窝信号、广播电视到卫星通信，移动用户可以自由地从一个标准漫游到另一个标准。各种业务应用、各种系统平台间的互联更便捷、安全，面向不同用户要求，更富有个性化。而且4G手机从外观和式样上看将有更惊人的突破，可以想象的是，眼镜、手表、化妆盒、旅游鞋都有可能成为4G终端。（四）智能性能更高第四代移动通信的智能性更高，不仅表现在4G通信的终端设备的设计和操作具有智能化，更重要的是4G手机可以实现许多难以想象的功能。例如，4G手机将能根据环境、时间以及其他因素来适时提醒手机的主人。三

46、、4G移动通信的接入系统4G移动通信接入系统的显著特点是，智能化多模式终端（multi-modeterminal）基于公共平台，通过各种接技术，在各种网络系统（平台）之间实现无缝连接和协作。在4G移动通信中，各种专门的接入系统都基于一个公共平台，相互协作，以最优化的方式工作，来满足不同用户的通信需求。当多模式终端接入系统时，网络会自适应分配频带、给出最优化路由，以达到最佳通信效果。目前，4G移动通信的主要接入技术有：无线蜂窝移动通信系统（例如2G、3G）；无绳系统（如DECT）；短距离连接系统（如蓝牙）；WLAN系统；固定无线接入系统；卫星系统；平流层通信（STS）；广播电视接入系统（如DAB

47、、DVB-T、CATV）。随着技术发展和市场需求变化，新的接入技术将不断出现。 不同类型的接入技术针对不同业务而设计，因此，我们根据接入技术的适用领域、移动小区半径和工作环境，对接入技术进行分层。 分配层：主要由平流层通信、卫星通信和广播电视通信组成，服务范围覆盖面积大。 蜂窝层：主要由2G、3G通信系统组成，服务范围覆盖面积较大。 热点小区层：主要由WLAN网络组成，服务范围集中在校园、社区、会议中心等，移动通信能力很有限。 个人网络层：主要应用于家庭、办公室等场所，服务范围覆盖面积很小。移动通信能力有限，但可通过网络接入系统连接其他网络层。 固定网络层：主要指双绞线、同轴电缆、光纤组成的固

48、定通信系统。 网络接入系统在整个移动网络中处于十分重要的位置。未来的接入系统将主要在以下三个方面进行技术革新和突破：为最大限度开发利用有限的频率资源，在接入系统的物理层，优化调制、信道编码和信号传输技术，提高信号处理算法、信号检测和数据压缩技术，并在频谱共享和新型天线方面做进一步研究。为提高网络性能，在接入系统的高层协议方面，研究网络自我优化和自动重构技术，动态频谱分配和资源分配技术，网络管理和不同接入系统间协作。提高和扩展IP技术在移动网络中的应用；加强软件无线电技术；优化无线电传输技术，如支持实时和非实时业务、无缝连接和网络安全。四、4G移动通信系统中的关键技术（一）定位技术 定位是指移动

49、终端位置的测量方法和计算方法。它主要分为基于移动终端定位、基于移动网络定位或者混合定位三种方式。在4G移动通信系统中，移动终端可能在不同系统（平台）间进行移动通信。因此，对移动终端的定位和跟踪，是实现移动终端在不同系统（平台）间无缝连接和系统中高速率和高质量的移动通信的前提和保障。（二）切换技术 切换技术适用于移动终端在不同移动小区之间、不同频率之间通信或者信号降低信道选择等情况。切换技术是未来移动终端在众多通信系统、移动小区之间建立可靠移动通信的基础和重要技术。它主要有软切换和硬切换。在4G通信系统中，切换技术的适用范围更为广泛，并朝着软切换和硬切换相结合的方向发展。 （三）软件无线电技术

50、在4G移动通信系统中，软件将会变得非常繁杂。为此，专家们提议引入软件无线电技术，将其作为从第二代移动通信通向第三代和第四代移动通信的桥梁。软件无线电技术能够将模拟信号的数字化过程尽可能地接近天线，即将A/D和D/A转换器尽可能地靠近RF前端，利用DSP进行信道分离、调制解调和信道编译码等工作。它旨在建立一个无线电通信平台，在平台上运行各种软件系统，以实现多通路、多层次和多模式的无线通信。因此，应用软件无线电技术，一个移动终端，就可以实现在不同系统和平台之间，畅通无阻的使用。目前比较成熟的软件无线电技术有参数控制软件无线电系统。 （四）智能天线技术 智能天线具有抑制信号干扰、自动跟踪以及数字波束

51、调节等智能功能，能满足数据中心、移动IP网络的性能要求。智能天线成形波束能在空间域内抑制交互干扰，增强特殊范围内想要的信号，这种技术既能改善信号质量又能增加传输容量。 （五）交互干扰抑制和多用户识别 待开发的交互干扰抑制和多用户识别技术应成为4G的组成部分，它们以交互干扰抑制的方式引入到基站和移动电话系统，消除不必要的邻近和共信道用户的交互干扰，确保接收机的高质量接收信号。这种组合将满足更大用户容量的需求，还能增加覆盖范围。交互干扰抑制和多用户识别两种技术的组合将大大减少网络基础设施的部署，确保业务质量的改善。 （六）新的调制和信号传输技术 在高频段进行高速移动通信，将面临严重的选频衰落（fr

52、equency-selectivefading）。为提高信号性能，研究和发展智能调制和解调技术，来有效抑制这种衰落。例如正交频分复用技术（OFDM）、自适应均衡器等。另一方面，采用TPC、Rake扩频接收、跳频、FEC（如AQR和Turbo编码）等技术，来获取更好的信号能量噪声比。五、结束语 对于现在的人来说，未来的4G通信的确显得很神秘，不少人都认为第四代无线通信网络系统是人类有史以来最复杂的技术系统。总的来说，要顺利、全面地实施4G通信，还将可能遇到一些困难。 首先，人们对未来的4G通信的需求是它的通信传输速度将会得到极大提升，从理论上说最高可达到100Mbit/s，但手机的速度将受到通信系统容量的限制。据有关行家分析，4G手机将很难达到其理论速度。 其次，4G的发展还将面临极大的市场压力。有专家预测，在10年以后，2G的多媒体服务将进入第三个发展阶段，此时覆盖全球的3G网络已经基本建成，全球25%以上的人口使用3G，到那时，整个行业正在消化吸收第三代技术，对于4G技术的接受还需要一个逐步过渡的过程。 因此，在建设4G通信网络系统时，通信运营商们将考虑直接在3G通信网络的基础设施之上，采用逐步引入的方法，使移动通信从3G逐步向4G过渡。