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Expectation-maximization vector approximate message passing-based frequency-domain turbo equalization for underwater
Xinrui Zhang1, Jun Tao1, Dong Li2
1Key Laboratory of Underwater Acoustic Signal Processing of the Ministry of Education, School of Information Science and Engineering, Southeast University, Nanjing 210096, China.
The Journal of the Acoustical Society of America
|November 21, 2023
Summary
This study introduces an enhanced frequency-domain turbo equalization (FDTE) for underwater acoustic communications. The new method learns noise power during equalization, improving performance in dynamic environments.
Area of Science:
- Signal Processing
- Underwater Communications
Background:
- Channel equalization is vital for single-carrier underwater acoustic (UWA) communications.
- Existing vector approximate message passing frequency-domain turbo equalization (VAMP-FDTE) requires pre-determined noise power, which is challenging in dynamic UWA environments.
Purpose of the Study:
- To develop an enhanced VAMP-FDTE scheme that learns noise power online.
- To improve the robustness and performance of UWA communication systems.
Main Methods:
- Proposed an enhanced VAMP-FDTE scheme incorporating the expectation-maximization (EM) algorithm for online noise power estimation.
- Utilized intermediate VAMP-FDTE results for EM-based noise power learning with minimal extra computational overhead.
Main Results:
- The enhanced VAMP-FDTE, named EM-VAMP-FDTE, demonstrated superior performance compared to the standard VAMP-FDTE.
- Experimental data from shallow-sea horizontal UWA communication trials with MIMO configuration validated the improved performance.
Conclusions:
- Online noise power learning via the EM algorithm significantly enhances VAMP-FDTE performance in UWA communications.
- The EM-VAMP-FDTE scheme offers a practical solution for UWA systems facing unknown and dynamic noise conditions.
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