dsss信号码序列恢复方法研究信号与信息处理专业论文.docxVIP

AbstractAbstract Abstract Abstract The spread spectrum communication technologies have been widely used bom组 military and commercial telecommunication areas，owing to the ability of working at low signal—to-noise ratio(SNR)．strong anti-jamming,difficult interception and mitigation of multi．path fading effects．The main work of mis thesis is to research the blind recovery algorithms of Pseudo Noise(PN)sequence，which is applied to the direct sequence spread spectrum(DSSS)signal．Generally,the DS commumcation contains three parts，including blind detection，parameters estimation and recovery of spreading sequence．However,as the recovery of PN sequence influences the performance of the whole system．the research at this domain iS quite urgent and significant at present． Firstly the previous and recent development of the recovery algorithms for PN sequence are summarized，then the basic theories are introduced and necessary experiments are given to verify the performance of all the mentioned approaches．finally appropriate comparison，analysis，explanation and conclusion are presented． The key work and innovations of this thesis mainly include： 1．The systematic research of the current PN sequence recovery algorithms．ne system mode is described with necessary details about the PN code sequence recovery theory which is based on the principal eigenvectors，as well as the recovery theory of the useful information．Several experiments are giVeil to analyze the performance of the information code recovery,which is controlled by the PN sequence． 2．Research of the classic modified sliding windows synchronization approaches and the typical subspace tracking algorithms．Wb first roughly introduced the sync栅omzation and asyncllromzation signal modes．and then a large number of experiments are given to demonstrate the performance of the pre-mentioned algorithms． 3．Modified the recovery algorithm which has better performance when the PN sequence is longer．By utilizing the subsection technique,th