Abstract

This article examines the effect of multipath channels on the performance of distributed arrays that employ time reversal. A model of the signal received from a distributed array is formulated, and a statistical analysis of the variation in signal power in the presence of phase noise and multipath is given. We present the impact these nonidealities have on received signal power, and we analyze the received power for three specific cases: continuous waveform, impulse waveform, and modulated rectangular pulse waveform in the presence of standard channel models. It is shown that for larger arrays in multipath channels, the change in power between coherent and incoherent states converges to the line-of-sight channel. It is further shown that in a line-of-sight channel time-reversal completely cancels unknown channel delays resulting in coherent signals from all nodes in a distributed array, while in a multipath channel only the main diagonal round-trip paths are coherent. Nevertheless, this additional benefit improves signal coherence in complex channels and can aide in distributed array synchronization using two-way time transfer.