Research On Low Detection Spread Spectrum Method Based On WFRFT

In this paper,the Weighted Fractional Fourier transform(WFRFT)is combined with the direct sequence spread spectrum system.Based on the low detection characteristics of the direct sequence spread spectrum system,the WFRFT and the direct spread system are organically combined to improve the low detection performance of the system.Firstly,the correlation characteristics of the spreading code sequence in the WFRFT domain are analyzed.From the mathematical theory analysis,the implementation of WFRFT on the spreading code sequence will weaken the correlation of the sequence.By analyzing the cross-correlation of the spreading code sequence in the time domain and its WFRFT domain,it can be seen that implementing WFRFT on the spreading code sequence can be used as a design method of the spreading code.Comparing WFRFT's gain and loss in direct sequence spread spectrum system,combining WFRFT with direct sequence spread spectrum system may further improve the low detection performance of wireless communication systems.Then,a Weighted Fractional Fourier-Direct Spread system(WFRFT-DS system)and a DS-WFRFT system are established,and the two systems are modeled and analyzed.Then,the relevant wave method is used as a method for detecting the spreading code period by the non-partner.Assuming that the correct spreading code period has been detected,the principal component analysis method is used as a method for detecting the spreading code pattern by th e non-partner.Finally,the impact of the transform order of the transceiver on the two systems is analyzed.Finally,a model of the multi-branch WFRFT-DS system is established,which integrates the k-WFRFT and the direct sequence spread spectrum system.The model of the transmitting end and the receiving end and the analysis of the calculation amount are analyzed.It is found that the computational complexity of the system is k times of the WFRFT-DS system(k is the number of branches of the system).Then,the relevant wave method is used to detect the spreading code period of the multi-branch WFRFT-DS system,and then it is assumed that the correct spreading code period has been detected,and the principal component analysis method is used to detect the spreading code pattern.Then use the relevant wave method to detect the spread spectrum code period of the multi-branch WFRFT-DS system,and then assume that the correct spread code period has been detected,and use the principal component analysis method to detect the spread code pattern of the multi-branch WFRFT-DS system.Finally,the influence of the conversion order of the transceiver on the multi-branch WFRFT-DS system is analyzed.It can be seen from the simulation results that the inconsistency of the transform order of the receiving end will affect the bit error rate of the multi-branch WFRFT-DS system,and the greater the difference of the transform order of the transceiver,the higher the bit error rate of the system.