Japan Agency for Marine-earth Science and Technology

Takuya Shimura

Yoshitaka Watanabe

Hiroshi Ochi

Mitsuyasu Deguchi

An acoustic communication system includes a first acoustic communication apparatus and a second acoustic communication apparatus. The first acoustic communication apparatus transmits a first acoustic wave to the second acoustic communication apparatus. The second acoustic communication apparatus transmits, as a response, a second acoustic wave to the first acoustic communication apparatus continuously in constant cycles until a next first acoustic wave is received. Each cycle includes a transmission period and a pause period. The first acoustic communication apparatus, which has received the second acoustic wave, determines a transmission timing that allows the next first acoustic wave to be received by the second acoustic communication apparatus based on a time period required from transmission of the first acoustic wave till reception of the second acoustic wave and the length of the transmission period, and transmits the next first acoustic wave to the second acoustic communication apparatus at the determined transmission timing.

Acoustic communication method and acoustic communication system

In order to efficiently compensate for effects of the Doppler shift, a receiving device includes a Doppler estimator that estimates a Doppler-shift frequency fdc of a received signal. A multiplier and an LPF detect the received signal based on a carrier frequency fc of the received signal and the Doppler-shift frequency fdc estimated by the Doppler estimator. A timing corrector corrects a timing T for extracting symbols of the received signal after detection by the LPF so as to track the Doppler shift. A symbol extractor extracts received symbols from the received signal after detection by the LPF at a timing corrected by the timing corrector. An adaptive equalizer estimates and determines symbols from the received symbols extracted by the symbol extractor.

Growing community of inventors

Yokosuka, Japan

Takuya Shimura