Abstract
Phase-coherent underwater acoustic (UWA) communication systems typically employ multiple hydrophones in the receiver to achieve spatial diversity gain. However, small underwater platforms can only carry a single transducer which can not provide spatial diversity gain. In this paper, we propose single-carrier with frequency domain equalization (SC-FDE) for phase-coherent synthetic aperture acoustic communications in which a virtual array is generated by the relative motion between the transmitter and the receiver. This paper presents synthetic aperture acoustic communication results using SC-FDE through data collected during a lake experiment in January 2016. The performance of two receiver algorithms is analyzed and compared, including the frequency domain equalizer (FDE) and the hybrid time frequency domain equalizer (HTFDE). The distances between the transmitter and the receiver in the experiment were about 5 km. The bit error rate (BER) and output signal-to-noise ratio (SNR) performances with different receiver elements and transmission numbers were presented. After combining multiple transmissions, error-free reception using a convolution code with a data rate of 8 kbps was demonstrated.
Highlights
Many approaches have been proposed for underwater acoustic (UWA) communications over the last two decades, including the single carrier with time-domain decision feedback equalizer (SC-TDE) [2,3], orthogonal frequency-division multiplexing (OFDM) [4], single-carrier with frequency domain equalization (SC-frequency domain equalizer (FDE)) [5,6,7,8], and time reversal communications [9,10]
The contributions of this paper include the following: (1) we proposed a SC-FDE approach for synthetic aperture UWA communications; (2) we analyzed the performances of two receiver algorithms, FDE and hybrid time frequency domain equalizer (HTFDE) using data collected from a lake experiment; and (3) we analyzed and compared the influence of receiver element number and transmission number on the performance of the SC-FDE based synthetic aperture communication method
The SC-FDE demodulator in Figure 2 consists of a down-converter, pseudorandom noise-based (PN) remover, fast Fourier transform (FFT), channel estimator, frequency domain equalizer, and inverse Fast Fourier Transform (IFFT)
Summary
Reliable underwater acoustic communications are challenging because of the limited bandwidths, time-varying multipath delay, double-selective channel fading, and strong background noise [1]. Non-coherent synthetic aperture time-reversal communications in shallow water was demonstrated at sea where only one transmitter and one receiver were required [15]. A glider with a single hydrophone is used for long-range acoustic communication in deep water [18] This system improved the performance even when individual receptions had low signal-to-noise ratios (SNR). The contributions of this paper include the following: (1) we proposed a SC-FDE approach for synthetic aperture UWA communications; (2) we analyzed the performances of two receiver algorithms, FDE and hybrid time frequency domain equalizer (HTFDE) using data collected from a lake experiment; and (3) we analyzed and compared the influence of receiver element number and transmission number on the performance of the SC-FDE based synthetic aperture communication method.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
