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现代移动通信 毕业论文外文翻译 (2)

一、英文原文Modern mobile communication technologyIn now highly the information 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 generation's core characteristic is the wide band addressing turns on non-gap roaming between the rigid network and numerous different communications system's, gains the multimedia communication services.Along with the time progress, the technical innovation, people's life request's 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 present's 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 techniqueThe 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 method's 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 complex and the Kathryn high frequency military channels. OFDM has used in 1.6 M bit/s high bit rate digital subscriber line (HDSL), 6 M bit/s asymmetrical digital subscriber line (ADSL), 100 M bit/s really high speed figure subscriber's line (VDSL), digital audio frequency broadcast and digital video broadcast and so on. OFDM applies on 5 GHz provides 54 M bit/s wireless local network IEEE 802.11 a and IEEE 802.11g, high performance this region network Hi per 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 communication's 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-fading's Rake receive and the track technology, the OFDMA technology which declines from the time domain and the frequencyrange resistance time and the frequency selectivity, the link auto-adapted technology, the union coding technique.2. frequency spectrum use factor lift techniqueThe 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 time's 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 24~34 dB, the frequency spectrum use factor is 20~40 bit/s/Hz. But launches and the receiving end uses 16 antennas, when 30 dB, the frequency spectrum use factor increases to 60~70 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 technologyThe 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 Processing 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 current 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 technologyThe 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 Processing 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 QoSQoS divides into wireless and the wired side two parts, wireless side's QoS involves theradio 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 side's QoS involves based on the IP differ discrimination service and the RSVP end-to-end resources reservation mechanism. Mechanism maps the wireless side IP differ 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 technologies' 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 people's daily life, for this reason, we needed to care that its trend of development, hoped it developed toward more and more convenient people's life's 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 management and intelligent management developmentSecond, network already from synchronized digital circuit to asynchronous digital grouping and asynchronous transfer mode (ATM) development;the three, software's 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;five, 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 16,000,000,000,000 /150MHz speed VLSI to 0.5 /350MHz speed VLSI and 2,000,000,000,000,000 /550MHz speed VLSI.Under this tendency's 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 communication 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 technology's development is progresses by leaps and bounds, presents the following several general trends: work service digitization, grouping; 2. networking wide band; working 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.二、英文翻译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”。

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