会议presentation PPT.ppt

PN Code Acquisition Method with Enhanced Sensitivity Performance * * Abstract Non-coherent integration （非相干积分）can enhance the performance of acquisition sensitivity in spread spectrum communication system with high bit rate, but it can not meet the requirements in low SNR environment due to the large loss of SNR. In this paper, a novel method is proposed for PN code（伪码） acquisition. Since the coherent integration time is extended by pre-judging the data sign, the loss of non-coherent integration is decreased. By pre-processing the coherent integration results before non-coherent integration, this method can get an achievable sensitivity gain, i.e. about 2 dB compared with direct non-coherent integration methods. Thus, the proposed method offers an effective way to improve the acquisition sensitivity performance. * * * Contents 2 Methods 4 Conclusions 1 Introduction 3 Results 1.1 Research scope 1.2 Present methods 1.3 My research 2.1 Signal model 2.2 Acquire method 2.3 Performance analysis * * * 1 Introduction Synchronization of PN code Core technology of spread spectrum communication Require the receivers to generate a local sequence which is identical with the received signals Two steps: acquisition and tracking. Only acquisition technology is considered 1.1Research Scope * * * 1 Introduction * Extend coherent integration time with assistance system High rate of data transmission is not easily implemented Present methods Non-coherent integration Large loss of SNR. Differential non-coherent integration Only be used in low rate condition 1.2 Present methods * * 1 Introduction Novel enhanced method Expand coherent integration time by pre-judging signal sign Enhanced acquisition sensitivity performance compared with direct coherent integration. * 1.3 My Research * * 2 Methods Spread spectrum communication system with high bit rate, a signal model with one bit period containing one PN code cycle After passing through a band-pass filter with