Real-time smart antenna system incorporating FPGA-based fast DOA estimator

This paper describes a practical hardware implementation of uplink smart antenna system useful for macrocellular base stations. This system incorporates a fast DOA (direction of arrival) estimator which is called UMP (unitary MUSIC processor) using the dedicated circuit device of FPGA (field programmable gate array). This system steers the mainlobe for the user basically with the Dolph-Chebyshev beam. In order to avoid undesirable interference reception by broad mainlobe, an optional null-steering processing cancels the interferers within the mainlobe coverage with notch beams which are pre-computed and stored in ROM (read only memory). The beamforming weight is computed by a simple convolution operation of the precomputed Dolph-Chebyshev beam and optional canceling beam, thus the computation load for weight generation is extremely small. This paper presents the estimation performance of the UMP through the hardware level fixed point simulation and measurements. And total performance evaluation of this system under AWGN and multipath fading channel with small angle spread is discussed.