Extrinsic information based enhanced Doppler compensation for high-speed underwater acoustic mobile communication

Abstract

In high-speed underwater acoustic mobile communication, achieving robust Doppler compensation is crucial due to the unpredictable changes in the Doppler factor. Due to the difficulty in optimizing Doppler estimation in turbo equalization through closed-form methods, a joint design of Doppler compensation, channel equalization, and decoding, is proposed to improve the accuracy of the Doppler compensation through integrated methods. Specifically, the proposed scheme utilizes extrinsic information provided by the decoder to evaluate the effectiveness of Doppler compensation because the extrinsic information indirectly reflects the accuracy of Doppler estimation. The proposed algorithm performs parallel Doppler resampling through multiple joint Doppler compensation, equalization, and decoding to optimize Doppler estimation by searching for the best extrinsic information. With iterative Doppler compensation and channel equalization, the accuracy of Doppler estimation is enhanced, leading to improved signal detection performance. The proposed algorithm was verified by underwater test data collected in Qiandao Lake, Hangzhou, China in May 2016. The results of this evaluation provide practical validation and demonstrate the effectiveness of the proposed algorithm in real-world underwater acoustic communication scenarios.