Performance prediction of passive time reversal communications

Abstract

A recent paper [M. Stojanovic J. Acoust. Soc. Am. 117, 1173-1185 (2005)] presented theoretical performance bounds of time reversal communications. In this letter, the performance of time reversal communications is evaluated using at-sea experimental data and compared to the theory for two different approaches; (1) time reversal alone and (2) time reversal combined with channel equalization. It is found that approach (1) shows a good agreement between theory and data. On the other hand, approach (2) indicates that the data is about 3-5 dB below the theory which assumes perfect knowledge of the channel, an infinite number of taps to remove the intersymbol interference, and no need for phase tracking. Taking these into consideration, the theoretical performance can provide a useful upper bound for predicting performance of time reversal communications.

Long-range time reversal communication in deep water: Experimental results

“…Both directions show a similar behavior in performance which initially improves rapidly with the first few elements and then gradually increases with an increase in the number of array elements. 16 Similar to Fig. 3(a), the output SNR follows closely the input SNR.…”

Time Reversal in Underwater Acoustic Communications

“…[26] proposed two algorithms to extend the basic passive time reversal technique by adaptively weighting sensor contributions to partially compensate for degraded focusing due to mismatch between the assumed and actual medium impulse responses. [27] presented theoretical performance bounds of time reversal communications via two different approaches: (1) time reversal alone and (2) time reversal combined with channel equalization. By taking advantages of spatial diversity using a number of receivers distributed in space, [28] presented the impact of spatial diversity in passive time reversal communications between a probe source and a vertical receiving array.…”

Wireless tomography, Part II: A system engineering approach

“…For example, adaptive filters or notch filters can be designed to cancel the interference. In acoustic communications, passive time reversal [8] [9] is used at the receiver to match the channel and the transmitted waveform. Thus waveform diversity has very broad meaning and significance.…”