Cross power spectral density based beamforming for underwater acoustic communications

OCEAN ENGINEERING

卷:216

Article

Li, Jianghui¹  Bai, Yechao²  Zhang, Youwen³  Qu, Fengzhong⁴  Wei, Yan⁴  Wang, Junfeng⁵ 

[1] Univ Southampton, Inst Sound & Vibrat Res, Southampton SO17 1BJ, Hants, England

[2] Nanjing Univ, Sch Elect Sci & Engn, Nanjing, Peoples R China

[3] Harbin Engn Univ, Coll Underwater Acoust Engn, Harbin, Peoples R China

[4] Zhejiang Univ, Ocean Coll, Hangzhou, Peoples R China

[5] Tianjin Univ Technol, Sch Elect & Elect Engn, Tianjin, Peoples R China

关键词: Beamforming;    Cross power spectral density (CPSD);    Direction of arrival;    Orthogonal frequency-division multiplexing (OFDM);    Underwater acoustic communications;   

DOI  :  10.1016/j.oceaneng.2020.107786

来源: Elsevier

【 摘 要 】

In underwater acoustic (UWA) communications, beamforming is often used to improve the detection performance of a receiver. For beamforming, there have been methods presented in time domain, e.g. fractional delay (FD) method, and in frequency domain, e.g. time-frequency-time with cross spectral density matrix (TFT-CSDM) method. The former brings accurate direction of arrival (DOA) estimation but with high complexity and is vulnerable to noise; while the latter brings less accuracy but with lower complexity. In this paper, we propose and investigate a time-frequency-time with cross power spectral density (TFT-CPSD) beamforming method for a vertical linear array (VLA) of hydrophones. The proposed method is compared with the FD and the TFT-CSDM methods in a receiver designed for guard-free orthogonal frequency-division multiplexing (OFDM) with super-imposed data and pilot signals. The comparison is based on data obtained in sea trials at distances 30-50 km in the northwest Pacific Ocean. The results demonstrate that the proposed TFT-CPSD method possesses higher accuracy than the TFT-CSDM method, and lower complexity than the FD method. Besides, the OFDM receiver with the TFT-CPSD beamforming outperforms a receiver with the TFT-CSDM beamforming and the FD beamforming at signal to noise ratio (SNR) -14 to 14 dB. The proposed beamforming technique possesses the merits of energy conservative and energy leakage reduction, which can also be applied to single-carrier transmission.

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