An underwater acoustic communication system and communication method based on frequency domain chirp spread spectrum

Abstract

The invention discloses a frequency domain chirp spread spectrum based hydroacoustic communication system and communication method. A sending end comprises a channel coding unit, a frequency domain chirp mapping unit, a subcarrier mapping unit, an inverse fast Fourier transform unit, a cyclic prefix adding unit and a windowing unit. A receiving end comprises a time synchronization unit, a carrier wave synchronization unit, a cyclic prefix removing unit, a multipath frequency mixing filtering unit, a chirp correlation demodulation unit, a channel decoding unit and a frequency tracking unit. Channel coding, frequency domain chirp mapping and subcarrier mapping are performed on input data at the sending end, and through inverse fast Fourier transform, cyclic prefix adding and windowing, signals are sent to a hydroacoustic channel; and a time synchronization, carrier synchronization and frequency tracking process is performed on receiving signals at a receiving end, cyclic prefixes are removed, frequency mixing filtering is performed on the receiving signals respectively with the central frequency of each piece of frequency domain chirp data so as to obtain signals after the multipath frequency mixing filtering, then chirp correlation demodulation is performed respectively with time domain up-chirp signals and time domain down-chirp signals, a result is determined, and through channel decoding, reduced data is output.

Description

technical field [0001] The invention relates to the field of underwater acoustic communication, in particular to an underwater acoustic communication system based on frequency domain chirp spread spectrum and a communication method thereof. Background technique [0002] With the development and utilization of marine resources, real-time voice transmission between underwater platforms and shore personnel and divers has become more important. Real-time voice communication is the most important and direct way of underwater communication, but underwater The environment of the acoustic communication channel is very complex, and it is randomly space-varying and time-varying; and it has the characteristics of serious multi-channel expansion, limited available bandwidth and high noise. It brings great difficulty to the transmission of images and voice, which makes long-distance reliable communication a difficult problem. [0003] For this complex and changeable underwater acoustic ...

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Problems solved by technology

[0004] The problem to be solved by the present invention is to overcome the problem of insufficient performance of the traditional Orthogonal Frequency Division Multiplexing (OFDM) underwater acoustic communication system and the high complexity of the system, and to provide an Multipath, anti-noise and anti-fading characteristics, and low-complexity underwater acoustic communication system based on frequency-domain chirp spread spectrum

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