无线宽带系统中信号检测技术研究.pdf

重庆大学硕士学位论文英文摘要 II ABSTRACT Broadband wireless communication systems offerhigh-speed data transmission services in wireless environment. By the employment of signal detection techniques, accurateacquisitionof the received signalis obtained to provide subsequent communication signal analysis and processing. Effected by the multipath fading, frequency offset and narrow-band interference, the narrowband system based traditional signal detection scheme can not meetthe requirementof the broadband system. Thus, it is an important issue to ensure the signal detection performance of wideband digital receiver in plicated channel. This thesis focuseson signal detectiontechniqueswhich usepseudo-random code sequences as main content of the thesis anizedas follows: This thesis analyzesthe signal detection technique of munication system employing the pseudo-random simulation results, it compares and analyzes detection performancesof the delayed correlation method,the conjugate multiplication algorithmand the matched filtering method. Since the CFAR (constant false alarm ratio) adaptive threshold techniqueis sensitive to frequency offset,thisthesis proposes an improved adaptive threshold detectionscheme. By combining thedelayed correlation technique andthe adaptive threshold detection technique, the frequency offset is removed and the detection performanceis guaranteedsimultaneously. Meanwhile, the proposedscheme decreases the probability of false alarm detection when thesignal to noise ratio increases by adding small offset. The simulation results show that the proposedscheme can maintain good detection performance in the large frequency offset environment wherethe frequency offset is timesas large asthe symbol rate. Asthe multipath fading affects the correlation peakvalue, the precise acquisition can not be , thisthesis proposes