Blind sorting of multiple FH signals in synchronous networking under underdetermined conditions

In order to improve the performance of network sorting under underdetermined conditions, this paper proposes a blind sorting method for multiple frequency hopping (FH) signals in synchronous networking based on the blind source separation. Firstly, the short-time Fourier transform is performed on the multiple FH signals received by the L-shaped antenna array, and the time-frequency map is denoised by using the adaptive threshold of the SNR. Then the time-frequency single-source-point (SSP) detection algorithm is used to get effective time-frequency SSP. The FH signal is segmented on the time-frequency diagram to detect the frequency hopping time. In a certain hopping time, carrier frequency and its corresponding mixing matrix is estimated. Finally, the DOA information of the FH signal is calculated according to the carrier frequency information and the estimated mixing matrix, and the multiple FH signals are sorted according to the DOA information. Theoretical research shows that multiple FH signals can be separated by only three receiving antennas, and simulation results verify the effectiveness of the proposed algorithm.