Communication apparatus, communication method, and program

A communication apparatus for performing acoustic communication underwater, the communication apparatus comprising:

• a forward adaptive equalization circuit configured to perform waveform equalization on a data frame acquired by the acoustic communication in chronological order;
• a backward adaptive equalization circuit configured to perform waveform equalization on the data frame in reverse chronological order;
• a likelihood synthesis circuit configured to calculate a likelihood, a likelihood ratio, or a log likelihood ratio, based on both first data of a first equalizer output from the forward adaptive equalization circuit and second data of a second equalizer output from the backward adaptive equalization circuit;
• and
• an error correction circuit configured to perform error correction of a data portion in the data frame based on the likelihood, the likelihood ratio, or the log likelihood ratio.

A communication method executed by a communication apparatus that performs acoustic communication underwater, comprising:

• performing first waveform equalization on a data frame acquired by the acoustic communication in chronological order;
• performing second waveform equalization on the data frame in reverse chronological order;
• and
• sequentially selecting and outputting one of first data of a first equalizer output by the first waveform equalization and second data of a second equalizer output by the second waveform equalization, or sequentially synthesizing and outputting both of the first data and the second data.