Examination of time-reversal acoustics and applications to underwater communications

Abstract

Recent experimental work [Roux et al., Appl. Phys. Lett. 70, 1811–1813 (1997); Kuperman et al., J. Acoust. Soc. Am. 103, 25–40 (1998)] has shown that the novel technique of time-reversal acoustics (TRA) can be applied in shallow-water environments to focus energy back at a source location from a transmitted signal received at a distant receiver array. This refocusing produces a local intensification of the field as well as a convergence of the signal in time. These two aspects of TRA techniques suggest it may be a viable approach for use in underwater communication systems. Because TRA techniques rely on the reconvergence of multipath information into focused arrivals at the original source locations, the influence of multipath spreading is removed. The energy transmitted is then enhanced by the focusing, thereby increasing the SNR. Specifically of interest in this study will be an analysis of how well the signal can be refocused in typical shallow-water environments and what type of data transfer rates can be achieved using TRA on realistic systems. [Work supported by ONR.]