现代移动通信外文翻译

现代移动通信外文翻译内容摘要：

FDM multichannel data transmission has succeeded uses in Kineplex and the Kathryn high frequency military channels. OFDM has used in Mbit/s high bit rate digital subscriber line (HDSL), 6 Mbit/s asymmetrical digital subscriber line (ADSL), 100 Mbit/s really high speed figure subscriber39。 s line (VDSL), digital audio frequency broadcast and digital video broadcast and so on. OFDM applies on 5 GHz provides 54 Mbit/s wireless local work IEEE a and IEEE , high performance this region work Hiper LAN/2 and ETSIBRAN, but also takes metropolitan area work IEEE and the integrated service digit broadcast (ISDBT) 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 munication39。 s another request is under the wide noise bandwidth, must demodulate the signaltonoise ratio to reduce as far as possible, thus increases the cover area. May adopt the antifading the full start power control and the pilot frequency auxiliary fast track demodulation technology, like the frequency range antifading39。 s 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 autoadapted 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 multiantenna 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 highcapacity wireless munication system uses one of technical. Bell Lab free time39。 s opposite angle BLAST (DBLAST) 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 multidiameter disturbance. VBLAST 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 autoadapted 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 autoadapted array antennas (AAA, Adaptive Array Antennas) disturb the counterbalance 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 munication services. It uses the digital signal processing language description telemunication 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), patible 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 concurrent 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 munication services. It uses the digital signal processing language description telemunication 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), patible 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 side39。 s 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 side39。 s QoS involves based on the IP diffSer discrimination service and the RSVP endtoend resources reservation mechanism. Mechanism maps the wireless side IP diffSer IP the QoS. Network security including work turning on security, core work security, application security, safety mechanism visibility and configurable. In the above modern mobile munication key technologies39。 s foundation, has had the land honeyb mobile munication, the satellite munication as well as the wireless Inter munication, these mailing address caused the correspondence appearance to have the huge change, used the digital technique the modern wireless munication already to permeate the national econ。