Broadband beamforming and null-steering based on fractional delay in OFDM systems

This paper proposes a method to perform simultaneous broadband beamforming and null-steering based on fractional delay filters. An analytical approach in the time domain is studied to obtain an instantaneous response for a fixed beamformer with very low complexity. The simulation of the beamformer in a broadband OFDM system shows the effectiveness of this method to improve the effective signal-to-interference-plus-noise-ratio. The process gain obtained by beam-steering improves the effective signal-to-noise-ratio reducing the BER, while the null-steering capacity guarantees the performance of the receiver even in scenarios with strong interferences.