Parameter-Free Landweber Iteration Method for Robust Adaptive Beamforming

In this paper, we propose a novel parameter-free Landweber iteration (LI) method to improve the robustness of a beamformer based on the LI algorithm and the L-curve criterion. The critical aspect of the proposed method is the automatic parameter selection procedure, which determines the iteration stop number in a scenario-dependent manner. This parameter-free method can flexibly adapt to different communication environments. To further improve the computational efficiency, an accelerated parameter-free LI method is also proposed that incorporates the Newton iteration into the LI algorithm without compromising the robustness of the beamformer. Numerical experiments demonstrate the effectiveness of the proposed beamformer.