Abstract:

Aiming at the problem of the traditional blind despread method for the direct sequence spread spectrum (DS-SS) signal, which needs to estimate spread spectrum sequence to complete the DS-SS signal blind despreading, a similarity based blind despread approach of DS-SS signal is proposed to solve the problem. Some parameters of DS-SS signals need to be known. Firstly, the received signal is divided into continuous non-overlapping temporal vectors according to one period of spread spectrum sequence, then their feature information matrix of similarity function value is constructed by calculating similarity function value of these vectors one by one. Finally, eigen value decomposition (EVD) is applied to the feature information matrix, and the blind estimation of the information sequence is obtained based on EVD. Theoretical analysis and simulation results show that the proposed method has high accuracy and good stability, which can effectively estimate the information sequence and spread spectrum sequence of the DSSS signals under the condition of signal-to-noise ratio (SNR) is -22 dB.