A coherent signal beamforming technique based on sub-array cross correlation

In this paper, a new coherent signal beamforming technique based on sub-array cross correlation (SCC) is proposed for the signal cancellation caused by traditional adaptive beamforming in multipath environment. Firstly, the array is uniformly divided into two mutual non-overlapped sub-arrays, and the preprocess of blocking expected signal is performed inside every sub-array to remove the expected signal component from the received signal on the premise that the direction of expected signal is known in advance. Then, minimum variance distortionless response (MVDR) allows us to obtain the desired signal with noise. Afterwards, based on the fact that the noise between different elements is not correlated, the MVDR output of one sub-array can be taken as the expected signal of the other sub-array to perform the beamforming with minimum mean square error (MMSE) criterion. Finally, the weight for the full array is obtained by combining the MMSE beamforming weights of the two sub-arrays. The proposed method can effectively solve the above coherent beamforming problem. What's more, the SCC beamformer performs well in the case with small samples. Both theoretical derivation and simulation experiment verify the feasibility and validity of the proposed beamformer.