Lake experimentation of in-band full-duplex underwater acoustic communications

Abstract

In-band full-duplex (IBFD) communications is a promising technique to achieve spectral-efficient communication in the underwater environment. Characteristics of self-interference and methods to suppress the self-interference are crucial to attaining IBFD acoustic communications. In this effort, we analyze the characteristic of the self-interference for the underwater acoustic channel through experimental measurements. Self-interference reduction using physical separation and digital cancellation is investigated under different transmitter-receiver geometries. An iterative IBFD receiver combining joint channel estimation, SI cancellation, and multichannel decision feedback equalizer is developed. The feasibility of coherent IBFD underwater acoustic communications was tested in a lake environment. The self-interference suppression methods and the receiver performance were evaluated using the experimental measurements. IBFD communications was demonstrated at 80 m. With 10 dB local self-interference source level reduction, IBFD communications was extended to the 170 m range. [Work supported by the National Science Foundation.]