Study On Acquisition Method Of Ambiguity Elimination In TDDM Signal

As an information transmission technology with great commercial value and military value,spread spectrum communication technology has become a research hotspot in countries around the world for its characteristics of strong anti-interference,low interception rate,good confidentiality,easy random access and easy realization of code division multiple access.With the continuous development of cross-filed technology integration of spread spectrum communication technology,the resources of the wireless transmission frequency band are becoming more and more tight,and the interference in the frequency band is getting more and more serious,which leads to a decrease in the anti-interference of the signal and the deterioration of the confidentiality.In this case,the research of a new generation of spread spectrum modulation signal becomes particularly important.In addition to the transition of spread spectrum pseudo-code from short period to long period and non-period,the modulation method of the new generation of spread spectrum modulation signal has undergone important changes.On the basis of the traditional modulation method,in order to better improve the quality of spread spectrum communication,and improve the anti-cheating and anti-imitation capabilities,the binary offset carrier modulation,improved binary offset carrier modulation and time division data modulation.such as time division data modulation with the unique time-division structure,improve the signal transmission of confidentiality,and improve the signal capture accuracy and greatly improve the ability of the spread spectrum modulation signal to adapt to the complex environment,but at the same time,the ambiguity of the reverse position caused by the baseband data reverse feature also brings new challenges for the receiver to correctly recover the baseband data.Therefore,this thesis mainly focuses on ambiguity elimination acquisition method of time division data modulation signal.Based on the study of the new generation of spread spectrum modulation signals,this thesis makes an in-depth study of the generation mechanism,related characteristics and spectral characteristics of TDDM signals,focusing on the mechanism of TDDM signal acquisition,aiming at the acquisition difficulty and inapplicability caused by the traditional acquisition method for the unique modulation mode of TDDM signals.Based on the characteristics of TDDM signal baseband data reverse feature,on the basis of the existing TDDM signal acquisition method,combined with the efficient spread spectrum modulation signal acquisition method,from the point of view of eliminating the position ambiguity of baseband data reverse,the ambiguity problem in the process of TDDM signal acquisition is deeply studied,and the ambiguity elimination acquisition method is proposed.In order to solve the ambiguity problem of baseband data reverse position during TDDM signal acquisition,an N-χ coefficient acquisition method was proposed.The method based on baseband data reverse position and parallel processing of relevant results to establish the linear relationship between the coefficient of χ sentence type,and based on the current accumulation time for N segment and measured the average of χcoefficients in each segment,in turn,it is concluded that the reverse location of baseband data,effectively solve the uncertainty problem of baseband data reverse position.Furthermore,a multi-channel acquisition method is proposed to solve the ambiguity problem of baseband data reverse position in the process of TDDM signal acquisition.On the basis of the dual-channel acquisition method,the method introduces other channels to make up for the shortcomings of the dual-channel acquisition method in eliminating the ambiguity at the accumulation time edge,and achieves the purpose of eliminating the reversal position ambiguity of baseband data.On the basis of the theory and method of description,the acquisition method of N-χ coefficient and multi-channel are simulated and analyzed.The simulation results show that the two new method proposed effectively eliminates the baseband data reverse position ambiguity problem in the TDDM signal acquisition process,at the same time has good effectiveness and advancement.