Simple null-steering OFDM adaptive array antenna for Doppler-shifted signal suppression

A new null-steering method to suppress Doppler-shifted signals is proposed for orthogonal frequency-division multiplexing adaptive array antenna. The proposed array antenna has a simple structure and can steer nulls for interfering signals even with small Doppler shifts by forcing virtual subcarrier outputs to be zero. A multistep recursive least-square algorithm is proposed to control the array weights and the bit-error rate and antenna pattern are evaluated by computer simulation.