Frequency-selective fading statistics of shallow-water acoustic communication channel with a few multipaths

Abstract

The bit error rate of an underwater acoustic communication system is related to multipath fading statistics, which determine the signal-to-noise ratio. The amplitude and delay of each path depend on sea surface roughness, propagation medium properties, and source-to-receiver range as a function of frequency. Therefore, received signals will show frequency-dependent fading. A shallow-water acoustic communication channel generally shows a few strong multipaths that interfere with each other and the resulting interference affects the fading statistics model. In this study, frequency-selective fading statistics are modeled on the basis of the phasor representation of the complex path amplitude. The fading statistics distribution is parameterized by the frequency-dependent constructive or destructive interference of multipaths. At a 16 m depth with a muddy bottom, a wave height of 0.2 m, and source-to-receiver ranges of 100 and 400 m, fading statistics tend to show a Rayleigh distribution at a destructive interference frequency, but a Rice distribution at a constructive interference frequency. The theoretical fading statistics well matched the experimental ones.

Enabling Higher-Order Modulation for Underwater Backscatter Communication

“…Second, higher backscatter rate would require larger bandwidth; however, since piezotransducers are typically narrow-band, this would result in lower SNR (signal-to-noise ratio). Finally, since the underwater channel is frequency-selective, spreading the signal over a wider bandwidth would complicate the decoding process [10], [11]. Despite these drawbacks, one might still want to adopt higher rates for certain data-intensive applications.…”

Design and performance evaluation of acoustic vehicle-to-pedestrian communication system

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