Shipborne Underwater Acoustic Communication System and Sea Trials with Submersible Shenhai Yongshi
The Shipborne acoustic communication system of the submersible Shenhai Yongshi works in vertical, horizontal and slant channels according to the relative positions. For ease of use, an array combined by a vertical-cone directional transducer and a horizontal-toroid one is installed on the mothership. Improved techniques are proposed to combat adverse channel conditions, such as frequency selectivity, non-stationary ship noise, and Doppler effects of the platform’s nonlinear movement. For coherent modulation, a turbo-coded single-carrier scheme is used. In the receiver, the sparse decision-directed Normalized Least-Mean-Square soft equalizer automatically adjusts the tap pattern and weights according to the multipath structure, the two receivers’ asymmetry, the signal’s frequency selectivity and the noise’s spectrum fluctuation. The use of turbo code in turbo equalization significantly suppresses the error floor and decreases the equalizer’s iteration times, which is verified by both the extrinsic information transfer charts and bit-error-rate performance. For noncoherent modulation, a concatenated error correction scheme of nonbinary convolutional code and Hadamard code is adopted to utilize full frequency diversity. Robust and low-complexity synchronization techniques in the time and Doppler domains are proposed. Sea trials with the submersible to a maximum depth of over 4500 m show that the shipborne communication system performs robustly during the adverse conditions. From the ten-thousand communication records in the 28 dives in 2017, the failure rate of the coherent frames and that of the noncoherent packets are both below 10%, where both synchronization errors and decoding errors are taken into account.
Key wordsunderwater acoustic communication turbo equalization human occupied vehicle high-speed shipborne communication system
Unable to display preview. Download preview PDF.
- Ahn, J., Yasukawa, S., Weerakoon, T., Sonoda, T., Nishida, Y., Ura, T. and Ishii, K., 2017. Sea-floor image transmission system for AUV, Proceedings of the IEEE OCEANS 2017-Aberdeen, IEEE, Aberdeen, UK, pp. 1–6.Google Scholar
- Freitag, L. and Singh, S., 2015. Performance of micro-modem PSK signaling with a mobile transmitter during the 2010 MACE experiment, Proceedings of the IEEE OCEANS 2015-Genova, IEEE, Genoa, Italy, pp. 1–7.Google Scholar
- Kurowski, M., Rentzow, E., Dewitz, D., Jeinsch, T., Lampe, B.P., Ritz, S., Kutz, R., Boeck, F., Neumann, S. and Oertel, D., 2015. Operational aspects of an ocean-going USV acting as communication node, Proceedings of the 15th Conference on Computer Applications and Information Technology in the Maritime Industries, Ulrichshusen, Germany, pp. 486–498.Google Scholar
- Potter, J., Alves, J., Green, D., Zappa, G., Nissen, I. and McCoy, K., 2014. The JANUS underwater communications standard, Proceedings of 2014 Underwater Communications and Networking, IEEE, Sestri Levante, Italy, pp.1–4.Google Scholar
- Roberts, P., Andronis, N. and Ghiotto, A., 2012. Voices from the deep–Acoustic communication with a submarine at the bottom of the Mariana Trench, Proceedings of Acoustics-Fremantle, Fremantle, Australia, pp.1–4.Google Scholar
- Suzuki, T., Wada, T., Yamada, H. and Nakagawa, S., 2017. A 31.8kbps/8kHz underwater acoustic single carrier frequency division multiplexing (SC-FDM) communication system with forward error correction, Proceedings of the IEEE OCEANS 2017-Anchorage, IEEE, Anchorage, AK, USA, pp. 1–5.Google Scholar
- Tao, J., 2016. Turbo equalization for MIMO SC-FDMA underwater acoustic communications, Proceedings of the OCEANS 2016 MTS/IEEE Monterey, IEEE, Monterey, CA, USA, pp. 1–5.Google Scholar
- Tao, J., An, L. and Zheng, Y.R., 2017. Enhanced adaptive equalization for MIMO underwater acoustic communications, Proceedings of the OCEANS 2017-Anchorage, IEEE, Anchorage, AK, USA, pp. 1–5.Google Scholar
- Wu, Y.B. and Zhu, M., 2014. Design and implementation of acoustic modem for shallow water network, Proceedings of 2014 IEEE International Conference on Signal Processing, Communications and Computing, IEEE, Guilin, China, pp. 900–904.Google Scholar
- Wu, Y.B., Zhu, M., Zhu, W.Q. and Xing Z.P., 2015a. Signal processing algorithm for noncoherent underwater acoustic communication approaching channel capacity, Acta Acustica, 40(1), 117–123. (in Chinese)Google Scholar
- Wu, Y.B., Zhu, M. and Li, X.G., 2015b. Sparse linear equalizers for turbo equalizations in underwater acoustic communication, Proceedings of OCEANS 2015-MTS/IEEE Washington, IEEE, Washington, DC, USA, pp. 1–6.Google Scholar
- Zhu, W.Q., Zhu, M., Wu, Y.B., Yang, B., Xu, L.J., Fu, X. and Pan, F., 2013. Signal processing in underwater acoustic communication system for manned deep submersible “Jiaolong”, Chinese Journal of Acoustics, 32(1), 1–15.Google Scholar