Time_Reversal_paper_Final.pdf (807.68 kB)
Download fileAn Information Theoretic Take on Time Reversal for Non-Stationary Channels
journal contribution
posted on 2014-01-09, 00:00 authored by Pawan Setlur, Natasha DevroyeIt has been shown that time-reversal (TR) techniques
focus energy back to the dominant scatters, lead to superresolution
focusing, and gains in detection. Time reversal has
so far mainly been studied when the channel remains invariant
between the initial and time-reversed signal transmission times.
In this letter, we relax this assumption and study the benefits
of TR over time-varying channels. To do so, we compare a
time-reversed and a non time-reversed system by comparing
the mutual information between the channel impulse response
and channel outputs given the transmitted signals. We present
analytical results for a simple scalar problem which illustrates
the impact of non-stationary channels on TR, and for general
channels, numerically evaluate the difference in mutual informations,
which demonstrate that, if the channels are non-stationary
yet correlated, TR may still provide mutual information gains
over non time-reversed systems.
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Institute of Electrical and Electronics EngineersLanguage
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