Acoustic MIMO communications in a very shallow water channel

Abstract

Underwater acoustic channels pose significant difficulty for the development of high speed communication due to highly limited band-width as well as hostile multipath interference. Enlightened by rapid progress of multiple input multiple output (MIMO) technologies in wireless communication scenarios, MIMO systems offer a potential solution by enabling multiple spatially parallel communication channels to improve communication performance as well as capacity. For MIMO acoustic communications, deep sea channels offer substantial spatial diversity among multiple channels that can be exploited to address simultaneous multipath and co-channel interference. At the same time, there are increasing requirements for high speed underwater communication in very shallow water area (for example, a depth less than 10 m). In this paper, a space-time multichannel adaptive receiver consisting of multiple decision feedback equalizers (DFE) is adopted as the receiver for a very shallow water MIMO acoustic communication system. The performance of multichannel DFE receivers with relatively small number of receiving elements are analyzed and compared with that of the multichannel time reversal receiver to evaluate the impact of limited spatial diversity on multi-channel equalization and time reversal processing. The results of sea trials in a very shallow water channel are presented to demonstrate the feasibility of very shallow water MIMO acoustic communication.

Keywords

underwater acoustic / underwater acoustic communication / multiple input multiple output (MIMO) / decision feedback equalizer (DFE) / very shallow water / multi-channel / time reversal

References

[1] Chitre MS, Shahabodeen S, Stojanovic M. Underwater acoustic communications and networking: Recent advances and future challenges. Marine Technology Society Journal, 2008, 42(1): 103-116

[2] Cotter SF, Rao BD. Sparse channel estimation via matching pursuit with application to equalization. IEEE Transactions on Communication, 2002, 50(3): 374-347

[3] Flynn JA, Ritcey JA, Rouseff D, Fox WLJ. Multichannel equalization by decision-directed passive phase conjugation: Experimental results. IEEE Journal of Oceanic Engineering, 2004, 29(3): 824-836

[4] Li W, Preisig JC. Estimation of rapidly time-varying sparse channels. IEEE Journal of Oceanic Engineering, 2007, 32(4): 927-939

[5] Ling J, Tan X, Yardibi T, Jian L, Nordenvaad ML, He H, Zhao K. On Bayesian channel estimation and FFT-based symbol detection in MIMO underwater acoustic communications. IEEE Journal of Oceanic Engineering, 2014, 39(1): 59-73

[6] Rouseff D, Badiey M, Song A. Effect of reflected and refracted signals on coherent underwater acoustic communication: Results from the Kauai experiment (KauaiEx 2003). Journal of the Acoustical Society of America, 2009, 126(5): 2359-2366

[7] Song A, Badiey M, McDonald VK, Yang TC. Time reversal receivers for high data rate acoustic multiple-input-multiple-ouput communication. IEEE Journal of Oceanic Engineering, 2011, 36(4): 525-538

[8] Song A, Badiey M, Song HC, Hodgkiss WS, Porter MB the KauaiEx Group Impact of ocean variability on coherent underwater acoustic communications during the Kauai experiment (KauaiEx). Journal of the Acoustical Society of America, 2008, 123(2): 856-865

[9] Song BG, Ritcey JA. Spatial diversity equalization for MIMO ocean acoustic communication channels. IEEE Journal of Oceanic Engineering, 1996, 21(4): 505-512

[10] Song HC, Hodgkiss WS, Kuperman WA. MIMO time reversal communications. Proceedings of the second workshop on Underwater networks (WuWNet’07), 2007, 5-10

[11] Song HC, Roux P, Hodgkiss WS, Kuperman WA, Akal T, Stevenson M. Mutiple-input-multiple-output coherent time reversal communications in a shallow-water acoustic channel. IEEE journal of Oceanic Engineering, 2006, 31(1): 170-178

[12] Stojanovic M. Efficient processing of acoustic signals for high-rate information transmission over sparse underwater channels. Physical Communications, 2008, 1(2): 146-161

[13] Tao J, Zheng YR, Xiao C, Yang TC. Robust MIMO underwater acoustic communication using turbo block decision-feedback equalization. IEEE Journal of Oceanic Engineering, 2010, 35(4): 948-960

[14] Wu FY, Zhou YH, Tong F, Kastner R. Simplified p-norm-like constraint LMS algorithm for efficient estimation of underwater acoustic channels. Journal of Marine Science and Application, 2013, 12(2): 228-234

[15] Yang TC. Correlation-based decision-feedback equalizer for underwater acoustic communications. IEEE Journal of Oceanic Engineering, 2005, 30(4): 865-880

[16] Zeng W, Jiang X, Li X, Zhang X. Deconvolution of sparse underwater acoustic multipath channel with a large time-delay spread. Journal of the Acoustical Society of America, 2010, 172(2): 909-919

[17] Zhou Y, Zeng K, Tong F, Chen Y. Selective time reversal receiver for underwater acoustic MIMO communications. Proceedings of MTS/IEEE OCEANS 2014, 2014, 1-6