Direct Sequence Spread Spectrum Coding To Capture Research

Because of having ascendant anti-jamming characteristic and multi-address capability in spread spectrum communication, it extensive have application in communication, medical treatment, measure and control. It is stress research problem to spread spectrum code acquisition and synchronization, acquisition time is important standard of spread spectrum communication performance.In the acquisition ways of the direct sequence spread spectrum code at present, all have their merit and shortage: traditional slippage correlation way need massive hardware scale to realization fast acquisition, serial integral and parallel integral have much less time than slippage correlation way, but their improve didn't excellence, SAW can application PN code quickly, but PN code digit less 256. In the acquisition ways of the direct sequence spread spectrum code, Sequence probability ratio test(SPRT) acquisition is a better way, acquisition time reduced 2 to 10 times compared with correlation acquisition way. It will improve the acquisition speed bigger if the hardware scale is appropriately added.In this paper, expatiated spread spectrum communication basis knowledge at first, summarized and compared to mostly direct spread spectrum code acquisition ways at present the second, at last, forward a new acquisition structure, namely parallel SPRT acquisition. It will improve the acquisition speed bigger if the hardware scale is appropriately added, and acquire the relation of acquisition time and parametersIntroduced wide interval frequency hopping in this paper also,. Aim at the problem of wide interval Frequency Hopping Processing Gain arithmetic in the common used, adopt modificatory arithmetic and calculated wide interval Frequency Hopping Processing Gain, analysis BER and anti-jamming ability.Aim at partly sub-carrier have deeply fading in MC-CDMA communication, proposed sub-carrier selection way. Transmitted the same power ,the way of sub-carrier selection have even better SNR and lower BER than using all sub-carrier.