Research On Communication Signals Separation Method Based On Blind Source Separation

The development of modern scientific and technological research has led the electromagnetic environment to a more complex level,a lot of new communication modes popped out,which makes useful signals pretty susceptible to all kinds of interference and noise from the electromagnetic environment.In an occasion where the interfering signals completely overlap weak useful signals in frequency domain under the single channel system model,to extract and precisely measure useful signals would become more difficult.Thus the demand of this detect-extract technique seems increasingly urgent.In this paper,we mainly studied the separation of weak signals in mixed-signal for single-channel model under strong interference and noise background.The signal separation algorithm based on low rank characteristic of time series is verified with theoretical analysis,simulation verification and actual signal separation experiment.Firstly,the signal mixing model of single channel is summarized,and the low order rank characteristic of time series which after matrixing process is studied.Based on the above theoretical analysis,a single channel weak signal separation algorithm based on RsPCA is proposed.Secondly,according to the sensitivity to noise in the algorithm model,the cost function and Augmented Lagrangian Optimization model based on the low-rank characteristic of the matrix are improved,and propose the n RsPCA algorithm under poor signal to noise ratio situation.The simulation results show that with little prior knowledge,the RsPCA algorithm can separate the signal even if the weak signal and the interfering signal are on the same carrier(the orthogonal condition is not satisfied)and the power is 0.01 times of the interference signal amplitude,the improved nRsPCA algorithm has about 2~5dB improvement in separation signal to interference ratio compared with the original algorithm at low signal-to-noise ratio,which will have a significant effect on effectively separating the weak signals hidden in strong interference.At last,the experimental results show that the proposed scheme can be used to verify the real signal transmission performance by using two USRP devices,in which weak test signals can be effectively separated from strong interference signals.