Effect of Multipaths on N-Ary Time Reversal Classifiers

The paper derives time reversal (TR) algorithms for N-ary classification problems and studies the impact of multipaths on the performance characteristics of these algorithms. The TR classifiers have the ability of detecting the presence or absence of a target in a rich cluttering environment with multipaths and of further classifying the detected targets either as an unknown enemy target or one of the known friendly targets. Compared to the conventional classifiers, the proposed TR classifier provides a gain of over 5dB at low SNRs. An analytical multipath model, based on geometric optics approximation with strong total internal reflection from the boundaries of the medium, is used to compare the effect of multipaths on the proposed classifiers versus the conventional algorithms.