An Efficient Broadband Null-Steering Beamformer for Interference Mitigation in Wireless Communication

It's often desirable using a null steering beamformer to mitigate strong broadband signals interference in wireless communication system. This paper proposes an efficient broadband null-steering beamformer based on an improved Davies Broadband Null-steering (DBN) algorithm combined with Improved Constant Modulus Algorithm (ICMA). The designed beamformer can impose adaptive broadband nulls at interferences without knowing directions in the sidelobe region by employing the ICMA for signal adaptation, while maintaining the main lobe toward the desired user direction. As evidenced by the reduced average output power convergence when compare to the existing DBN algorithm, the designed broadband beamformer improved convergence rate by 16.9%. Thus, the new algorithm is observed to have much faster convergence behavior.