Realization of adaptive beamforming in smart antennas on a reconfigurable architecture

Abstract

This paper proposes an efficient beamforming algorithm that suits well in smart antennas for the secured wireless communications. Also, its subsequent implementation methodology on a reconfigurable structure of the Field Programmable Gate Arrays (FPGA) chip is presented. As antenna unit, a linear array with uniform inter-element spacing and non-uniform element excitations is considered. With reference to a pre-specified template of Cosine-squared beamforming function, array element excitation coefficients are determined iteratively with well-known Particle Swarm Optimization (PSO) technique. Adaptive beamformer circuit is realized with Finite State Machine (FSM) modeling and COordinate Rotation DIgital Computer (CORDIC) functional blocks. System performance is evaluated under the Additive White Gaussian Noise (AWGN) and Rayleigh fading channel conditions. Multiple fixed-point hardware level simulations are made on the Xilinx Virtex-4 environments and the results in terms of beamforming accuracy and system complexities so obtained with less errors and lower computational overheads, corroborate its competency compared to the existing systems.