外文资料翻译-吴挺智.doc

大连民族学院毕业设计外文资料翻译所 在 学 院：信息与通信工程学院专 业 (班级)： 电子101 学 生 姓 名： 吴挺智 指 导 教 师： 于少华 徐道明 2014年2月9日 10现代移动通信在日益增长的移动业务市场需求的推动下，3G技术正在逐步走向应用。从目前3G网络商用情况看，用户市场与运营商对3G的期望与网络实际应用之间存在一定的差距。在3G初期，众多的移动通信领域专家与学者们都预期3G将成为一个彻底实现普遍灵活、多样化、个性化的5A（Anyone，Anywhere，Anytime，Anydevice，Anything）方式的无缝隙宽带接入的解决方案，在网络统一性、业务综合性、服务多样性方面，3G将成为用户的理想选择。但是，随着规范制定、产品实现、网络商用、业务提供等多方面的发展，可以看出，现有的WCDMA，cdma2000，TD-SCDMA三类技术在应用方面都面临困境。认清这些问题，对于在移动通信产业发展中占据重要位置的移动运营商而言，具有重要的战略意义。从移动运营商角度来看，网络技术包括产品实现技术与网络运营技术。实现技术的综合性能影响网络运营技术，而网络运营技术又能够推动产品实现技术。这里结合对3G网络技术体系的理解，就应用方面面临的问题给予剖析。对于3G产品实现技术而言，面临的最大问题就是如何实现产品性能多方面“软性”特征的平衡与稳定。3G系统中采用的CDMA无线接入技术的复杂程度远远超过2G系统的GSM技术。CDMA技术以统计复用方式进行无线资源利用，用户区分采用码字方式，用户在时间、频谱方面呈共用特征，为了降低这种“共用”造成的“自干扰性”实现用户侧的高质量话音与数据业务，3G网络需要在物理层、链路层、网络层引入多项关键无线技术，包括功率控制、软切换、多用户检测、智能天线、无线资源管理等，而对于每一项关键技术，不仅向下包含多类实现方式，而且横向与其它技术之间相关联。功率控制是克服CDMA系统中的“远近效应”采用的一项关键技术，以实现用户之间的功率平衡，同时保证系统覆盖与容量之间的平衡。与GSM相比，3G系统对功率控制的依赖程度很大，并且功率控制的精度与速度直接影响到网络性能。在功率控制的实现过程中，基站与手机的响应速度门限及可变性特征是限制功率控制速度的客观因素，用户的移动性与无线环境的复杂性是限制功率控制精度的客观因素。由于这两方面的客观因素存在，功率控制在3G的技术规范中不能给出明确限定值。因此，功率控制技术在实现及应用方面呈限制性与不确定性，这些特征一方面直接映射到3G网络性能中，另一方面通过与其它技术（例如软切换）的相关性间接体现到3G网络性能中，这两方面将导致了网络性能的“软特性”。在当今高度信息化的社会，信息和通信已成为现代社会的“命脉”。信息的交流主要依赖于计算机通信，而通信作为传输手段，与传感技术、计算机技术相互融合，已成为21世纪国际社会和世界经济发展的强大动力。为了适应时代的要求，新的一代移动通信技术应时而生，新的一代移动通信技术即人们称之第三代的核心特征是宽带寻址接入到固定网和众多不同通信系统间的无隙缝漫游，获取多媒体通信业务。随着时代的进步、科技的创新、人们的生活要求的提高，移动通信技术更新换代速度相当惊人，差不多每隔十年移动通信技术就发生一次变革性换代，从上个世纪80年代的“大哥大”到现在的3G手机，其间发生了两次移动通信技术的变革，从1G的AMPS过渡到2G的GSM，从GSM到IMT-2000（即3G技术）。就我所知现代的移动通信技术有以下几方面的重要技术：1.宽带调制和多址技术无线高速数据传输不能一味仅靠频谱的扩展，应在频谱效率上至少高于目前一个数量级，可在物理层采用三项技术，即OFDM、UWB和空时调制编码。OFDM与其他编码方式的结合，灵活把OFDM与TDMA、FDMA、CDMA、SDMA组合成多址技术。20世纪60年代OFDM的多路数据传输已成功用于Kineplex和Kathryn高频军事通信系统。OFDM已用于1.6 Mbit/s高比特率数字用户线（HDSL），6 Mbit/s不对称数字用户线（ADSL），100 Mbit/s甚高速数字用户线（VDSL），数字音频广播和数字视频广播等。OFDM应用于5 GHz上提供54 Mbit/s无线本地网IEEE 802.11 a和IEEE 802.11g，高性能本地域网络Hiper LAN/2和ETSI-BRAN，还作为城域网IEEE 802.16和集成业务数字广播（ISDB-T）标准。与单载频调制制式相比，OFDM调制制式要解决相对大的峰均功率比（PAPR，Peak to Average Power Ratio）和对频率位移和相位噪声敏感的问题。高速移动通信的另一要求是在宽噪声带宽下，所需解调信噪比应尽可能降低，从而增加覆盖面积。可采取抗衰落的快速发射功率控制和导频辅助快速跟踪相干解调技术，如频域抗衰落的Rake接收和跟踪技术，从时域和频域抵抗时间和频率选择性衰落的OFDMA技术，链路自适应技术，联合编码技术。2.频谱利用率提升技术理论研究指出：在独立Rayleigh散射信道中，数据速率与天线数成线性关系，容量可达Shannon的90%。在发射和接收端以多天线开发信道空间可取得容量和频谱效率的增益。MIMO技术主要包括空间复用和空间分集技术，在独立信道上并发或连发相同信息来提高传输可靠性。收发双方的空间分集是高容量无线通信系统采用技术之一。贝尔实验室分层次空时的对角BLAST（D-BLAST）容量的增加为收发双方最小天线数的函数。利用MIMO所构成的跨时域和空域的扩展信号还可以抵抗多径干扰。V-BLAST系统在室内2434 dB时，频谱利用率为2040 bit/s/Hz。而发射和接收端均采用16天线，在30 dB时，频谱利用率增至6070 bit/s/Hz。智能天线自动跟踪所需信号和自适应空时处理算法，利用天线阵产生空间定向波束，通过数字信号处理技术使主波束对准用户信号到达方向，旁瓣或零陷对准干扰信号到达方向。自适应阵列天线（AAA，Adaptive Array Antennas）中干扰抵消均衡器（ICE，Interference Canceling Equalizer）可减少干扰和降低发射功率。3.软件无线电技术软件无线电技术是在硬件平台上通过软件编辑以一个终端实施不同系统中多种通信业务。它用数字信号处理语言描述电信元件，以软件程序下载成数字信号处理硬件（DSPH，Digital Signal Pocessing Hardware）。以具有通用开放无线结构（OWA，Open Wireless Architecture），兼容多种模式在多种技术标准之间无缝切换。UWB也称为脉冲无线电，调制采用脉冲宽度在纳秒级的快速上升和下降脉冲，脉冲覆盖的频谱从直流至吉赫兹，不需常规窄带调制所需的射频上变换，脉冲成型后可直接送至天线发射。4.软件无线电技术软件无线电技术是在硬件平台上通过软件编辑以一个终端实施不同系统中多种通信业务。它用数字信号处理语言描述电信元件，以软件程序下载成数字信号处理硬件（DSPH，Digital Signal Pocessing Hardware）。以具有通用开放无线结构（OWA，Open Wireless Architecture），兼容多种模式在多种技术标准之间无缝切换。5.网络安全和QoSQoS分为无线和有线侧两部分，无线侧的QoS涉及无线资源管理和调度，接纳控制和移动性管理等，移动性管理主要包括终端移动性，个人移动性和业务移动性。有线侧的QoS涉及基于IP diffSer的区分业务和RSVP的端到端资源预留机制。把IP diffSer的IP QoS机制映射到无线侧。网络安全包括网络接入安全，核心网安全，应用安全，安全机制可见性与可配置性。在上述现代移动通信关键技术的基础上，产生了陆地蜂窝移动通信、卫星通信以及无线因特网通信技术，这些通信方式使通信面貌发生了巨大的变化，采用数字技术的现代无线通信已经渗入国民经济的各个领域和人们的日常生活，为此，我们需要关心它的发展趋势，希望它朝着越来越方便人们的生活的方向发展，现在就让我们来看看现代移动通信的未来发展趋势吧。现代移动通信技术发展的七个新趋势:一、移动管理已从终端管理向个人管理和智能管理发展二、网络已从同步的数字电路向异步的数字分组和异步传递方式(ATM)发展;三、软件的开发已从算法驱动到面向过程和面向目标的趋势发展;四、信息处理已从话音发展到数据和图像;五、无线频谱的处理已从窄带模拟向窄带CDMA发展;六、计算机已从集中式处理发展到分布式服务器和智能化处理;七、半导体器件已从每芯片16兆门/150MHz速率的VLSI发展到0.5千兆门/350MHz速率的VLSI和2千兆门 /550MHz速率的 VLSI。在这种趋势的引导下，移动通信业务迅猛发展，它满足了人们在任何时间、任何地点与任何个人进行通信的愿望。移动通信是实现未来理想的个人通信服务的必由之路。在信息支撑技术、市场竞争和需求的共同作用下，移动通信技术的发展更是突飞猛进，呈现出以下几大趋势：1)网络业务数据化、分组化；2)网络技术宽带化；3)网络技术智能化；4)更高的频段；5)更有效利用频率；6)各种网络趋于融合。了解、掌握这些趋势对移动通信运营商和设备制造商均具有重要的现实意义。Modern mobile communication technology Mobileservicesinthegrowingmarketdemanddriven,3Gtechnologyisgraduallyapplied.Commercial3Gnetworkfromthecurrentsituation,theusermarketandtheexpectationsof3Goperatorsandnetworkexistsbetweenthepracticalapplicationofthegap.Intheearly3G,manymobilecommunicationexpertsandscholarsareexpectedto3Gwillbeacompletelyuniversalandflexible,diversified,individualized5A(Anyone,Anywhere,Anytime,Anydevice,Anything)methodofseamlessbroadbandaccesssolutions,theunityinthenetwork,businessintegration,servicediversity,3Gwillbetheidealchoiceforusers.However,withthespecificationdevelopment,productrealization,networkbusiness,serviceprovisionandotheraspectsofdevelopment,wecansee,theexistingWCDMA,cdma2000,TD-SCDMAtechnologyintheapplicationofthreearefacingdifficulties.Clearunderstandingoftheseissuesinthemobilecommunicationsindustryforthedevelopmentofanimportantpositiontooccupythemobileoperators,hasimportantstrategicsignificance.Fromtheperspectiveofmobileoperators,networktechnologies,includingproducts,technologyimplementationtechnologyandnetworkoperations.Productstoachievetheoverallperformanceoftechnicalnetworkoperationstechnologies,andnetworkoperators,technologyandimplementationtechniquestopromotetheproduct.Thissystem,combinedwiththeunderstandingof3Gnetworktechnologytotheproblemsfacingtheapplicationofgivenanalysis.Implementationtechnologyfor3Gproducts,thebiggestproblemishowtoachievevariousperformancesoftcharacteristicsofbalanceandstability.3GCDMAsystem,wirelessaccesstechnologyusedinthecomplexityofthesystemfarmorethan2GGSMtechnology.CDMAwirelesstechnologyinthewayofstatisticalmultiplexingofresources,theuserdistinguishtheuseofcodewords,theuseratthetime,thefrequencyspectrumwassharedcharacteristics,inordertoreducethiscommoncauseself-interferencetoachievehigh-qualityvoiceusersideanddataservices,3Gnetworksneedinthephysicallayer,linklayer,networklayerintoanumberofkeywirelesstechnologies,includingpowercontrol,softswitching,multi-userdetection,smartantennas,radioresourcemanagement,andforeachofthekeytechnologiesnotonlydowntoincludemanytypesofimplementations,andbetweenthehorizontalandothertechnologiesassociated.Belowthepowercontroltechnology,forexample,analysisofproductrealizationtechnologyproblems.CDMApowercontrolsystemtoovercomethedistanceeffectakeytechnologyusedtoachieveabalanceofpowerbetweenusers,whileensuringthatthesystembalancebetweencoverageandcapacity.ComparedwithGSM,3Gsystemsdependentonlargepowercontrolandpowercontrolaccuracyandspeeddirectlyaffectsthenetworkperformance.Therealizationofthepowercontrolprocess,thebasestationandmobilespeedofresponseandvariabilitycharacteristicsofthethresholdistolimitthepowercontrolthespeedofobjectivefactors,theusersmobileandwirelessenvironmentistolimitthecomplexityofthepowercontrolaccuracyoftheobjectivefactors.Sinceboththeobjectivefactorsexist,thepowercontrolin3Gspecificationscannotgiveaclearlimit.Therefore,thepowercontroltechnologyandapplicationsintherealizationwasrestrictiveanduncertainties,whichfeaturestheonehand,mapdirectlytothe3Gnetworkperformance,theotherhand,withothertechnologies(suchassofthandover)isreflectedindirectlyrelatedtothe3Gnetworkperformanceinboththenetworkperformancewillleadtosoftfeatures.In now highly the informationization society, the information and the correspondence have become the modern society “the life”. The information exchange mainly relies on the computer correspondence, but corresponds takes the transmission method, with the sensing technology, the computer technology fuses mutually, has become in the 21st century the international society and the world economic development powerful engine. In order to of adapt the time request, the new generation of mobile communication technology seasonable and lives, the new generation of mobile communication technology is the people said that third generations core characteristic is the wide band addressing turns on non-gap roaming between the rigid network and numerous different communications systems, gains the multimedia communication services. Along with the time progress, the technical innovation, peoples life requests enhancement, the mobile communication technology renewal speed is quite astonishing, almost every other ten year mobile communication technology has a transformation update, from the 1980s “the mobile phone” to presents 3G handset, during has had two mobile communication technology transformation, transits from 1G AMPS to 2G GSM, from GSM to IMT-2000 (i.e. 3G technology). Knows modern on me the mobile communication technology to have the following several aspect important technology: 1. wideband modulation and multiple access technique The wireless high speed data transmission cannot only depend on the frequency spectrum constantly the expansion, should be higher than the present number magnitude at least in the frequency spectrum efficiency, may use three technologies in the physical level, namely OFDM, UWB and free time modulation code. OFDM with other encoding methods union, nimbly OFDM and TDMA, FDMA, CDMA, SDMA combines the multiple access technique. In the 1960s the OFDM multi-channel data transmission has succeeded uses in Kineplex and the Kathryn high frequency military channels. OFDM has used in 1.6 Mbit/s high bit rate digital subscriber line (HDSL), 6 Mbit/s asymmetrical digital subscriber line (ADSL), 100 Mbit/s really high speed figure subscribers line (VDSL), digital audio frequency broadcast and digital video broadcast and so on. OFDM applies on 5 GHz provides 54 Mbit/s wireless local network IEEE 802.11 a and IEEE 802.11g, high performance this region network Hiper LAN/2 and ETSI-BRAN, but also takes metropolitan area network IEEE 802.16 and the integrated service digit broadcast (ISDB-T) the standard. Compares with the single load frequency modulation system service pattern, the OFDM modulation service pattern needs to solve the relatively big peak even power ratio (PAPR, Peak to Average Power Ratio) and to the frequency shifting and the phase noise sensitive question. High speed mobile communications another request is under the wide noise bandwidth, must demodulate the signal-to-noise ratio to reduce as far as possible, thus increases the cover area. May adopt the anti-fading the full start power control and the pilot frequency auxiliary fast track demodulation technology, like the frequency range anti-fadings Rake receive and the track technology, the OFDMA technology which declines from the time domain and the frequency range resistance time and the frequency selectivity, the link auto-adapted technology, the union coding technique. 2. frequency spectrum use factor lift technique The fundamental research pointed out: In the independent Rayleigh scattering channel, the data rate and the antenna several tenth linear relationships, the capacity may reach Shannon 90%. Is launching and the receiving end may obtain the capacity and the frequency spectrum efficiency gain by the multi-antenna development channel space. The MIMO technology mainly includes the spatial multiplying and the space diversity technology, concurrent or the salvo same information enhances the transmission reliability on the independent channel. Receives and dispatches the bilateral space diversity is the high-capacity wireless communication system uses one of technical. Bell Lab free times opposite angle BLAST (D-BLAST) capacity increase to receive and dispatch the bilateral smallest antenna number in administrative levels the function. The cross time domain which and the air zone expansion signal constitutes using MIMO may also resist the multi-diameter disturbance. V-BLAST system when indoor 2434 dB, the frequency spectrum use factor is 2040 bit/s/Hz. But launches and the receiving end uses 16 antennas, when 30 dB, the frequency spectrum use factor increases to 6070 bit/s/Hz. The smart antenna automatic tracking needs the signal and the auto-adapted free time processing algorithm, produces the dimensional orientation wave beam using the antenna array, causes the main wave beam alignment subscriber signal direction of arrival through the digital signal processing technology, the side lobe or zero falls the alignment unwanted signal direction of arrival. The auto-adapted array antennas (AAA, Adaptive Array Antennas) disturbs the counter-balance balancer (ICE, Interference Canceling Equalizer) to be possible to reduce disturbs and cuts the emissive power. 3. software radio technology The software radio technology is in the hardware platform through the software edition by a terminal implementation different system in many kinds of communication services. It uses the digital signal processing language description telecommunication part, downloads the digital signal processing hardware by the software routine (DSPH, Digital Signal Pocessing Hardware). By has the general opening wireless structure (OWA, Open Wireless Architecture), compatible many kinds of patterns between many kinds of technical standards seamless cut. UWB is also called the pulse to be radio, the modulation uses the pulse width in the nanosecond level fast rise and the drop pulse, the pulse cover frequency spectrum from the cocurrent to the lucky hertz, does not need in the radio frequency which the convention narrow band frequency modulation needs to transform, after pulse formation, may deliver directly to the antenna launch. 4. software radio technology The software radio technology is in the hardware platform through the software edition by a terminal implementation different system in many kinds of communication services. It uses the digital signal processing language description telecommunication part, downloads the digital signal processing hardware by the software routine (DSPH, Digital Signal Pocessing Hardware). By has the general opening wireless structure (OWA, Open Wireless Architecture), compatible many kinds of patterns between many kinds of technical standards seamless cut. 5. network security and QoS QoS divides into wireless and the wired side two parts, wireless sides QoS involves the radio resource management and the dispatch, the admission control and the mobility management and so on, the mobility management mainly includes the terminal mobility, individual mobility and service mobility. Wired sides QoS involves based on the IP diffSer discrimination service and the RSVP end-to-end resources reservation mechanism. Mechanism maps the wireless side IP diffSer IP the QoS. Network security including network turning on security, core network security, application security, safety mechanism visibility and configurable.In the above modern mobile communication key technologiess foundation, has had the land honeycomb mobile communication, the satellite communication as well as the wireless Internet communication, these mailing address caused the correspondence appearance to have the huge change, used the digital technique the modern wireless communication already to permeate the national economy each domain and peoples daily life, for this reason, we needed to care that its trend of development, hoped it developed toward more and more convenient peoples lifes direction, will let now us have a look at the modern mobile communication the future trend of development. modern mobile communication technological development seven new tendencies :First, mobility management already from terminal management to individual mana