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1、1Modern 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 method, with the sensi
2、ng 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
3、 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. the mobile communication technolog
4、y 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 freque
5、ncy 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
6、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
7、and digital video broadcast and so on. OFDM applies on 5 GHz provides 54 Mbit/s 2wireless 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 (ISD
8、B-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 spe
9、ed 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 technolo
10、gy, 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 fac
11、tor 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 efficie
12、ncy 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 sp
13、ace 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 zo
14、ne expansion signal constitutes using MIMO may also resist the multi-diameter disturbance. V-BLAST system 3when 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
15、/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 t
16、echnology, 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 commun
