Adaptive Constrained Constant Modulus Algorithm Based on Auxiliary Vector Filtering for Beamforming

A constrained constant modulus (CCM) algorithm with the auxiliary vector filtering (AVF) technique is introduced for robust adaptive beamforming. The proposed scheme decomposes the adaptive filter into constrained (reference vector filters) and unconstrained (auxiliary vector filters) components. The weight vector is iterated by subtracting the scaling auxiliary vector from the reference vector, which are computed according to the CCM criterion. The proposed algorithm provides an iterative exchange of information between the scalar factor and the auxiliary vector, resulting in a faster convergence and an improved steady-state performance as compared with existing techniques with large filters. The convergence properties of the proposed algorithm are analyzed. Simulation results show that the proposed beamforming algorithm outperforms existing techniques and is robust against signature mismatch problems.