Underwater Acoustic Communication Using Time Reversal Equalization
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Solution Overview
Problem
Algorithms for underwater acoustic communication, such as Doppler estimation and resampling compensation, require high computational complexity and power consumption, making them unsuitable for micro-AUVs due to their limited resources and frequent Doppler variations during variable-speed movements.
Innovation Solution
A method involving time reversal processing with adaptive gradient iteration of time reversal coefficients, combining time reversal and equalization to suppress Doppler effects without resampling, using forward and backward shift equalizers and adaptive algorithms to reduce computational complexity and improve communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Doppler estimation and resampling compensation algorithms are used to suppress Doppler effects, then Doppler suppression performance is improved, but computational complexity and power consumption increase significantly
Solution Approach 1:
The patent combines time reversal processing with equalization processing into a unified framework. The time reversal coefficients are used directly as equalizer coefficients, merging two separate signal processing functions into one integrated process, thereby reducing computational complexity while maintaining Doppler suppression performance
Solution Approach 2:
The patent changes the parameter representation by using time reversal coefficients (which capture multipath information) directly as equalizer coefficients instead of performing separate channel estimation and equalization. This parameter transformation eliminates the need for complex resampling operations while preserving Doppler compensation capability
2Reliability
If passive time reversal technique with frequent channel estimation is used to achieve Doppler suppression, then Doppler suppression performance is maintained, but communication efficiency decreases due to frequent processing
Solution Approach 1:
The patent performs time reversal processing using previously obtained channel multipath information before actual data transmission. By preparing the time reversal coefficients in advance during training or synchronization phases, the system avoids the need for frequent channel estimation during data transmission, thereby maintaining Doppler suppression while improving communication efficiency
3Reliability
If micro-AUVs use traditional underwater acoustic communication systems with high computational power requirements, then Doppler suppression capability is improved, but system cost and power consumption increase
Solution Approach 1:
The patent extracts and utilizes the inherent multipath information contained in the received signal through time reversal processing, eliminating the need for separate, power-intensive channel estimation and equalization algorithms. This extraction approach reduces computational load and power consumption while maintaining Doppler suppression capability suitable for energy-constrained micro-AUVs
Data Source
AI summary
A method for underwater acoustic communication includes steps of S1: capturing a synchronization signal using a cross-correlation operation; S2: performing time forward shifting and reversing processing and time backward shifting and reversing processing, respectively, on the synchronization signal to obtain a forward shifted time reversal coefficient and a backward shifted time reversal coefficient; S3: performing a convolution operation of the forward shifted time reversal coefficient and the backward shifted time reversal coefficient, respectively, with a subsequently captured information sequence to obtain a forward shifted time reversal output and a backward shifted time reversal output; S4: processing the forward shifted time reversal output and the backward shifted time reversal output, respectively, with a forward shift equalizer and a backward shift equalizer to obtain two sets of equalizer outputs; and S5: selecting one of the two sets of equalizer outputs with a smaller error for data decoding to obtain a desired signal.