{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:40:43Z","timestamp":1760240443878,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2019,6,17]],"date-time":"2019-06-17T00:00:00Z","timestamp":1560729600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the National Natural Science Foundation of Shandong, China","award":["ZR2017MD019"],"award-info":[{"award-number":["ZR2017MD019"]}]},{"name":"the National\u2002Science\u2002Foundation\u2002for\u2002Post-doctoral\u2002Scientists\u2002of\u2002China","award":["2017M621248"],"award-info":[{"award-number":["2017M621248"]}]},{"name":"Shanghai Aerospace Science and Technology Innovation Funding, China","award":["SAST2017-001"],"award-info":[{"award-number":["SAST2017-001"]}]},{"name":"Experimental Technology Research Foundation of Qufu Normal Universtiy, China","award":["SJ201723"],"award-info":[{"award-number":["SJ201723"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Filtered multitone (FMT) modulation divides the communication band into several subbands to shorten the span of symbols affected by multipath in underwater acoustic (UWA) communications. However, there is still intersymbol interference (ISI) in each subband of FMT modulation degrading communication performance. Therefore, ISI suppression techniques must be applied to FMT modulation UWA communications. The suppression performance of traditional adaptive equalization methods often exploited in FMT modulation UWA communications is limited when the effect of ISI spans tens of symbols or large constellation sizes are used. Turbo equalization consisting of adaptive equalization and channel decoding can improve equalization performance through information exchanging and iterative processes. To overcome the shortcoming of traditional minimum mean square error (MMSE) equalization and effectively suppress the ISI with relatively low computation complexity, an FMT modulation UWA communication using low-complexity channel-estimation-based (CE-based) MMSE turbo equalization is proposed in this paper. In the proposed method, turbo equalization is first exploited to suppress the ISI in FMT modulation UWA communications, and the equalizer coefficients of turbo equalization are adjusted using the low-complexity CE-based MMSE algorithm. The proposed method is analyzed in theory and verified by simulation analysis and real data collected in the experiment carried out in a pool with multipath propagation. The results demonstrate that the proposed method can achieve better communication performance with a higher bit rate than the FMT modulation UWA communication using traditional MMSE adaptive equalization.<\/jats:p>","DOI":"10.3390\/s19122714","type":"journal-article","created":{"date-parts":[[2019,6,17]],"date-time":"2019-06-17T03:24:41Z","timestamp":1560741881000},"page":"2714","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Filtered Multitone Modulation Underwater Acoustic Communications Using Low-Complexity Channel-Estimation-Based MMSE Turbo Equalization"],"prefix":"10.3390","volume":"19","author":[{"given":"Lin","family":"Sun","sequence":"first","affiliation":[{"name":"College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China"},{"name":"School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mei","family":"Wang","sequence":"additional","affiliation":[{"name":"Electro-Mechanical Engineering Institute, Shanghai 201109, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Guoheng","family":"Zhang","sequence":"additional","affiliation":[{"name":"Beijing Great Wall Electronic Equipment Co., Ltd, Beijing 100082, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Haisen","family":"Li","sequence":"additional","affiliation":[{"name":"College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China"},{"name":"Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China"},{"name":"Key Laboratory of Marine Information Acquisition and Security, Ministry of Industry and Information Technology, Harbin Engineering University, Harbin 150001, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lan","family":"Huang","sequence":"additional","affiliation":[{"name":"College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,6,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/S0065-3454(05)35004-2","article-title":"Acoustic communication in noise","volume":"35","author":"Brumm","year":"2005","journal-title":"Adv. Study Behav."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1109\/MCOM.2009.4752682","article-title":"Underwater acoustic communication channels: Propagation models and statistical characterization","volume":"47","author":"Stojanovic","year":"2009","journal-title":"IEEE Commun. Mag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1109\/MCOM.2009.4752683","article-title":"Signal processing for underwater acoustic communications","volume":"47","author":"Singer","year":"2009","journal-title":"IEEE Commun. Mag."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1621","DOI":"10.1121\/1.408135","article-title":"Adaptive multichannel combining and equalization for underwater acoustic communications","volume":"93","author":"Stojanovic","year":"1993","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"905","DOI":"10.1121\/1.4812762","article-title":"Efficient use of bandwidth for underwater acoustic communication","volume":"134","author":"Song","year":"2013","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1867","DOI":"10.1049\/iet-com.2014.1176","article-title":"Single-carrier underwater acoustic communication combined with channel shortening and dichotomous coordinate descent recursive least squares with variable forgetting factor","volume":"9","author":"Sun","year":"2015","journal-title":"IET Commun."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1638","DOI":"10.1109\/JSAC.2008.081204","article-title":"Detection, synchronization, and Doppler scale estimation with multicarrier waveforms in underwater acoustic communication","volume":"26","author":"Mason","year":"2008","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1650","DOI":"10.1109\/JSAC.2008.081205","article-title":"Iterative carrier frequency offset and channel estimation for underwater acoustic OFDM systems","volume":"26","author":"Kang","year":"2008","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1109\/JOE.2013.2253212","article-title":"Adaptive OFDM modulation for underwater acoustic communications: Design considerations and experimental results","volume":"39","author":"Radosevic","year":"2014","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_10","first-page":"251","article-title":"Differentially coherent multichannel detection of acoustic OFDM signals","volume":"4","author":"Skinder","year":"2015","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1109\/JOE.2014.2323365","article-title":"Adaptive modulation and coding for underwater acoustic OFDM","volume":"40","author":"Wan","year":"2015","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.apacoust.2014.11.013","article-title":"Experimental demonstration of differential OFDM underwater acoustic communication with acoustic vector sensor","volume":"91","author":"Chi","year":"2015","journal-title":"Appl. Acoust."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Gomes, J., and Stojanovic, M. (2009, January 26\u201329). Performance analysis of filtered multitone modulation systems for underwater communication. Proceedings of the IEEE International Conference on Oceans, Biloxi, MS, USA.","DOI":"10.23919\/OCEANS.2009.5422175"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/j.apacoust.2016.11.018","article-title":"Multiple-input multiple-output passive time reversal acoustic communication using filtered multitone modulation","volume":"119","author":"Li","year":"2017","journal-title":"Appl. Acoust."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1109\/JOE.2013.2291139","article-title":"Filterbank multicarrier communications for underwater acoustic channels","volume":"40","author":"Amini","year":"2015","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Silva, L., and Gomes, J. (2015, January 18\u201321). Sparse Channel estimation and equalization for underwater filtered multitone. Proceedings of the IEEE International Conference on Oceans, Genoa, Italy.","DOI":"10.1109\/OCEANS-Genova.2015.7271739"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"22357","DOI":"10.3390\/s150923554","article-title":"Time reversal acoustic communication using filtered multitone modulation","volume":"15","author":"Sun","year":"2015","journal-title":"Sensors"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"953","DOI":"10.1016\/j.apacoust.2011.06.004","article-title":"Experimental assessment of a multicarrier underwater acoustic communication system","volume":"72","author":"Zhang","year":"2011","journal-title":"Appl. Acoust."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1109\/78.984761","article-title":"Minimum mean squared error equalization using a priori information","volume":"50","author":"Tuchler","year":"2002","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1109\/JOE.2015.2398731","article-title":"Iterative Channel estimation and turbo equalization for multiple-input multiple-output underwater acoustic communications","volume":"41","author":"Yang","year":"2016","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1109\/MCOM.2015.7321975","article-title":"Turbo equalization for single-carrier underwater acoustic communications","volume":"53","author":"Zheng","year":"2015","journal-title":"IEEE Commun. Mag."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"920","DOI":"10.1109\/TIT.2010.2096033","article-title":"Turbo equalization: An overview","volume":"57","author":"Tuchler","year":"2011","journal-title":"IEEE Trans. Inf. Theory"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1109\/JOE.2011.2158013","article-title":"Adaptive linear turbo equalization over doubly selective channels","volume":"36","author":"Choi","year":"2011","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3813","DOI":"10.1109\/TSP.2011.2147782","article-title":"Enhanced MIMO LMMSE turbo equalization: Algorithm, simulations, and undersea experimental results","volume":"59","author":"Tao","year":"2011","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1109\/JOE.2008.925893","article-title":"Underwater acoustic communications: Long-term test of turbo equalization in shallow water","volume":"33","author":"Otnes","year":"2008","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"4925","DOI":"10.1109\/TVT.2015.2470646","article-title":"Bidirectional soft-decision feedback turbo equalization for MIMO systems","volume":"65","author":"Duan","year":"2016","journal-title":"IEEE Trans. Veh. Technol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/12\/2714\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:58:56Z","timestamp":1760187536000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/12\/2714"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,6,17]]},"references-count":26,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2019,6]]}},"alternative-id":["s19122714"],"URL":"https:\/\/doi.org\/10.3390\/s19122714","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2019,6,17]]}}}