Multi-input and multi-output selectivity OFDM underwater sound communication system and method

Abstract

The invention relates to a multi-input and multi-output selectivity OFDM underwater sound communication system and a method thereof, having the advantages of resisting multi-path interference, resisting frequency selectivity deep fading, improving the transmission rate of information and the like. The transmitter of the system comprises a space multiplexing unit, a plurality of spectrum spreading units, a subcarrier zero setting unit, a plurality of OFDM modulation units, a multiple sonar transmitting unit and a communication channel estimation unit, wherein, the spectrum spreading units are connected between the space multiplexing unit and the subcarrier zero setting unit; the OFDM modulation units are connected between the subcarrier zero setting unit and the multiple sonar transmitting unit. A receiver comprises a multiple sonar receiving unit, a plurality of OFDM demodulation units, a communication channel frequency domain balancing unit, a plurality of dispreading units and space demultiplexing units, the OFDM demodulation units are connected between the multiple sonar receiving unit and the communication channel frequency domain balancing unit, the dispreading units are connected between the communication channel frequency domain balancing unit and the space demultiplexing unit, and the communication channel estimation unit is respectively connected with the subcarrier zero setting unit and the communication channel frequency domain balancing unit.

Description

technical field [0001] The invention relates to the technical field of underwater acoustic communication, in particular to a multiple-input multiple-output selective orthogonal frequency division multiplexing underwater acoustic communication system and method. Background technique [0002] Underwater acoustic communication technology is an important means in contemporary marine resource development, monitoring, and military defense. Compared with radio communication and wired communication, underwater acoustic channel is a time-varying, space-varying, and frequency-varying random narrow-band channel, with severe multipath Interference and Doppler frequency deviation are the main reasons for the high bit error rate of underwater acoustic communication. Factors such as multipath propagation effects, ocean current influence, and energy propagation on the seabed cause signal time domain broadening, which causes frequency selective fading; The relative movement between platforms...

AI Technical Summary

Problems solved by technology

To a certain extent, MIMO technology can utilize multipath components in propagation, that is to say, MIMO can resist multipath fading, but MIMO technology is still powerless against the frequency selective fading that exists in underwater acoustic channels.

[0006] To sum up, in view of the shortcomings of MIMO technology in frequency selective fading channels, OFDM technology is introduced to overcome it, but it is necessary to make appropriate adjustments to the allocation of subcarriers in OFDM technology to adapt to the underwater environment. At the same time, MIMO technology can be used To increase the transmission rate to make up for the shortcomings of the communication rate drop due to spread spectrum

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