Adaptive beamforming using variable step-size LMS algorithm with novel ULA array configuration

This paper proposes a new array geometry and a variable step-size (VSS) LMS algorithm to improve adaptive beamforming in smart antenna systems. The beamformer based on the proposed array geometry coupled with the use of VSSLMS is capable of resolving signals arriving from narrowband sources propagating plane waves close to the array endfire. The proposed array configuration comprises of doubly crossed uniform linear arrays (ULAs) so that the size and computational load of the proposed array is identical to that of a 2N-element conventional ULA, while beamforming accuracy and angular resolution are higher for narrowband signals arriving at directions close to the array endfire. Performance of the VSSLMS algorithm and proposed ULA configuration is investigated with respect to the variation of a number of parameters related to the signal environment and array itself. Results of numerical simulation are used to design smart antenna systems with optimal performance.