Waveform Shaping for Time Reversal Interference Cancellation: A Time Domain Approach

In this paper, we present a time domain interference cancellation scheme using time reversal, in time reversal, a signal, for example, transmitted by a weak source through a dispersive medium, is received by an array, time reversed, power normalized, and retransmitted through the same medium. If the channel is reciprocal, and the clutter is sufficiently rich, the retransmitted waveform refocuses on the original source. This focusing effect implies that a significant portion of the received signal energy concentrates in a very small time/space, support compared with the rest of the signal components. In this paper, we consider the opposite problem: rather than refocusing, we reshape the retransmitted waveform to reduce the returned echo, i.e., to mitigate the clutter returns. Proof of concept is provided using experimental electromagnetic data and wave propagation simulations.