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1、 本文由宏哥1015贡献 doc文档可能在WAP端浏览体验不佳。建议您优先选择TXT，或下载源文件到本机查看。 现代移动通信 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
2、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
3、 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） Mbit/s ，6 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
4、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。 1 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
5、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
6、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（O
7、WA，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 Arc
8、hitecture） ，兼容多种模式在多种技术标准之 2 间无缝切换。 5.网络安全和 QoS QoS 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
9、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
10、; 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
11、和设备制造商均具有重要的 现实意义。 3 Modern mobile communication technology 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 m
12、ethod, 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,
13、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 th
14、e 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, dur
15、ing 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 tec
16、hnique 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 m
17、odulation code. OFDM with other encoding methods union, nimbly OFDM and TDMA, FDMA, CDMA, SDMA combines the multiple access technique. 4 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
18、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 IE
19、EE 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 mod
20、ulation 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-
21、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 whic
22、h 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, t
23、he 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 5 technology mainly includes the spatial
24、 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 ti
25、mes 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 syste
26、m 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 al
27、gorithm, 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-adapt
28、ed 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 ed
29、ition 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 t
30、he general opening wireless structure (OWA, 6 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
31、 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 tec
32、hnology 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
33、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 p
34、arts, 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 dis
35、crimination 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
36、mobile communication key technologiess foundation, has had the land honeycomb mobile communication, the 7 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
37、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 communica
38、tion the future trend of development. modern mobile communication technological development seven new tendencies : First, mobility management already from terminal management to individual management and intelligent management development Second, network already from synchronized digital circuit to
39、asynchronous digital grouping and asynchronous transfer mode (ATM) development; the three, softwares developments actuated from the algorithm to the procedure-oriented and face the goal tendency development; the four, information processing have developed from the voice to the data and the image; fi
40、ve, wireless frequency spectrum processing already from narrow band simulation to the narrow band CDMA development; the six, computers have developed from central processing to the distributional server and intellectualized processing; the seven, semiconductor devices have developed from each chip 1
41、6,000,000,000,000 /150MHz speed VLSI to 0.5 /350MHz speed VLSI and 2,000,000,000,000,000 /550MHz speed VLSI. Under this tendencys guidance, the mobile service rapid development, it satisfied the people in any time, any place to carry on the correspondence with any individual the desire. The mobile c
42、ommunication 8 realizes in the future the ideal person-to-person communication service way that must be taken. In the information support technology, the market competition and under the demand combined action, the mobile communication technologys development is progresses by leaps and bounds, prese
43、nts the following several general trends: 1) network service digitization, grouping; 2) networking wide band; 3) networking intellectualization; 4) higher frequency band; 5) more effective use frequency; 6) each kind of network tends the fusion. The understanding, grasps these tendencies has the vital practical significance to the mobile communication operator and the equipment manufacturer. 91