A Modified RC-pLMS Adaptive Beamformer for Secure Digital Communication

Abstract

A modified reduced complexity parallel least mean square (mRC-pLMS) adaptive beamforming algorithm for high precision directivity and secure data communication is proposed in this paper. A high performance RC-pLMS algorithm has been proposed, recently, to eliminate the tradeoff between the LMS steady state error and its convergence speed while maintaining a low computational complexity structure. RC-pLMS is obtained by simplifying the two stages parallel LMS (pLMS) and adding a filter to the inputs, thus eliminating the need of an additional LMS filter. To further improve the RC-pLMS convergence speed and accuracy for fast and secure data communication we propose a modified RC-pLMS algorithm. mRC-pLMS is obtained by updating the RC-pLMS weight update equation to make use of the filtered input signal rather than the original input. Numerical simulations reflected by the mean square error convergence behavior and beam pattern, demonstrate the superior performance of the mRC-pLMS in providing faster convergence, lower steady state error and better interference attenuation while maintaining identical RC-pLMS resource requirements.