Source Number Estimation for Synchronous DSCDMA Signal with Same Direction of Arrival

For the problem that the performance of the estimation method of the number of sources in DS-CDMA system with close direction is seriously degraded or even failed. A segmented reconstruction source number estimation method for Synchronous DS-CDMA Signal is proposed. Firstly, the signals received by each array element are segmented to form a new matrix, and then the covariances matrices of all the reconstructed signals are averaged. Finally, the judgment criterion is constructed by calculating the derivative of ratio of adjacent eigenvalues, and then the estimation of the number of sources is achieved. The method takes advantage of the irrelevance between the spread spectrum codes and reconstructs the guidance matrix, which can estimate the number of sources with the same arrival direction. The theoretical analysis and simulation results show that this method is suitable for both white noise and colored noise background, and has good estimation performance under low SNR, At the same time, this method can achieve the estimation of source number stably even when the number of array elements is less than the number of sources.