Multiple Antenna Time Reversal Transmission in Ultra-Wideband Communications

In this paper we study the multiple antenna time reversal downlink transmission in an ultra-wideband (UWB) communication system which consists of access points and users. The access point has multiple antennas and the user has a single antenna. We design the UWB beamformer that focuses on the intended user while minimizing its interference on unintended users and eavesdropping access points. We show that the designed UWB beamformer is equivalent to the time reversal focusing and nulling schemes and yields better performance than the conventional delay line wideband beamformer. We verify our results using experimentally measured electromagnetic data in an indoor environment.