Application of conjugate gradient algorithm to adaptive beamforming

In this paper, the relationship of subarray size, snapshot number and interference number is studied for different gradient computing methods. New forward and backward CGM (FBCGM) and multilayer FBCGM (MFBCGM) methods are proposed. Their advantages are summarized as follows: (1) they can be applied with a small number of snapshots. (2) They can be applied with a weaker constraint for the number of the array elements than that Mandyam (1997). (3) They perform well in coherent receiving environments. (4) They have less computational load compared to SMI and the subspace projection method.