{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T21:50:16Z","timestamp":1770069016892,"version":"3.49.0"},"reference-count":33,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T00:00:00Z","timestamp":1769990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JSAN"],"abstract":"<jats:p>Underwater wireless optical communication (UWOC) has emerged as a key enabler for Internet of Underwater Things (IoUT) and autonomous sensing networks, but its reliability is severely affected by salinity-induced attenuation, scattering, and turbulence. This work presents a high-speed and salinity-resilient UWOC architecture that jointly exploits Polarization Division Multiplexing (PDM) and Multiple-Input Multiple-Output (MIMO) diversity to enhance link capacity and robustness in realistic oceanic conditions. Two 1 Gbps NRZ data channels at 1550 nm were transmitted using continuous-wave lasers and evaluated using a hybrid OptiSystem\u2013MATLAB simulation framework with full channel modeling of absorption, scattering, turbulence, and salinity (32\u201336 ppt). Results reveal that the proposed PDM-MIMO system achieves more than an order-of-magnitude bit-error-rate (BER) reduction compared with non-MIMO or single-polarization baselines, maintaining acceptable BER levels up to 20 m. Performance degradation with increasing salinity is quantified, and results confirm that combined PDM and spatial diversity effectively mitigate salinity-induced losses. The presented design demonstrates a viable and scalable solution for next-generation underwater sensing and communication networks in coastal and deep-sea ecosystems.<\/jats:p>","DOI":"10.3390\/jsan15010017","type":"journal-article","created":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T09:48:08Z","timestamp":1770025688000},"page":"17","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mitigating Salinity Effects in UWOC Using Integrated Polarization-Multiplexed MIMO Architecture"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1715-9689","authenticated-orcid":false,"given":"Sushank","family":"Chaudhary","sequence":"first","affiliation":[{"name":"School of Computer, Guangdong University of Petrochemical Technology, Maoming 525000, China"},{"name":"Department of Electrical Engineering, Chulalongkorn University, Bangkok 10330, Thailand"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1007\/s11235-025-01279-x","article-title":"Underwater communication technologies: A review","volume":"88","author":"Theocharidis","year":"2025","journal-title":"Telecommun. Syst."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Mohsan, S.A.H., Li, Y., Sadiq, M., Liang, J., and Khan, M.A. (2023). Recent advances, future trends, applications and challenges of internet of underwater things (iout): A comprehensive review. J. Mar. Sci. Eng., 11.","DOI":"10.3390\/jmse11010124"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Domingos, F.P.F., Lotfi, A., Ihianle, I.K., Kaiwartya, O., and Machado, P. (2024). Underwater communication systems and their impact on aquatic life\u2014A survey. Electronics, 14.","DOI":"10.3390\/electronics14010007"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"896832","DOI":"10.1155\/2015\/896832","article-title":"Underwater sensor network applications: A comprehensive survey","volume":"11","author":"Felemban","year":"2015","journal-title":"Int. J. Distrib. Sens. Netw."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Fang, C., Li, S., Wang, Y., and Wang, K. (2023). High-speed underwater optical wireless communication with advanced signal processing methods survey. Photonics, 10.","DOI":"10.3390\/photonics10070811"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"131025","DOI":"10.1016\/j.optcom.2024.131025","article-title":"Performance investigation of a VLC-PDM based UWOC system under adverse underwater conditions with varying chlorophyll levels","volume":"573","author":"Chaudhary","year":"2024","journal-title":"Opt. Commun."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"937","DOI":"10.1515\/joc-2022-0063","article-title":"Underwater wireless optical communications links: Perspectives, challenges and recent trends","volume":"45","author":"Mohammed","year":"2024","journal-title":"J. Opt. Commun."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"7350414","DOI":"10.1109\/JPHOT.2022.3195700","article-title":"Current trend in optical internet of underwater things","volume":"14","author":"Guo","year":"2022","journal-title":"IEEE Photonics J."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1109\/JLT.2019.2960131","article-title":"A review on practical considerations and solutions in underwater wireless optical communication","volume":"38","author":"Sun","year":"2020","journal-title":"J. Light. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Abrar, A.S., and Rani, M. (2025). Underwater visible light communication: Recent advancements and channel modeling. J. Opt., 1\u201315.","DOI":"10.1007\/s12596-025-02839-9"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Chaudhary, S., Sharma, A., Khichar, S., Shah, S., Ullah, R., Parnianifard, A., and Wuttisittikulkij, L. (2023). A salinity-impact analysis of polarization division multiplexing-based underwater optical wireless communication system with high-speed data transmission. J. Sens. Actuator Netw., 12.","DOI":"10.3390\/jsan12050072"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Zhou, Y., Ming, J., Wang, L., Wu, D., Zhao, L., and Xiao, J. (2022). Optical polarization division multiplexing transmission system based on simplified twin-SSB modulation. Sensors, 22.","DOI":"10.3390\/s22207700"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"210127","DOI":"10.29026\/oea.2022.210127","article-title":"Optical multiplexing techniques and their marriage for on-chip and optical fiber communication: A review","volume":"5","author":"Khonina","year":"2022","journal-title":"Opto-Electron. Adv."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Chaudhary, S., Meng, Y., Sharma, A., and Naeem, M.A. (2024). MIMO and PDM-based intersatellite optical link for high-speed data transfer and remote sensing application. PLoS ONE, 19.","DOI":"10.1371\/journal.pone.0313342"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Naeem, M., De Pietro, G., and Coronato, A. (2021). Application of reinforcement learning and deep learning in multiple-input and multiple-output (MIMO) systems. Sensors, 22.","DOI":"10.3390\/s22010309"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1827","DOI":"10.1007\/s11277-018-5718-1","article-title":"Effects of modulation scheme on experimental setup of RGB LEDs based underwater optical communication","volume":"106","author":"Mangrio","year":"2019","journal-title":"Wirel. Pers. Commun."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"105298","DOI":"10.1109\/ACCESS.2019.2929738","article-title":"A simplified form of beam spread function in underwater wireless optical communication and its applications","volume":"7","author":"Saxena","year":"2019","journal-title":"IEEE Access"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"163153","DOI":"10.1016\/j.ijleo.2019.163153","article-title":"System parameters effect on the turbulent underwater optical wireless communications link","volume":"198","author":"Vali","year":"2019","journal-title":"Optik"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1080\/1064119X.2019.1569739","article-title":"Analysis on the effect of salinity in underwater wireless optical communication","volume":"38","author":"Kumar","year":"2020","journal-title":"Mar. Georesources Geotechnol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"10027","DOI":"10.1364\/OE.390311","article-title":"Experimental demonstration of an underwater wireless optical communication employing spread spectrum technology","volume":"28","author":"Lyu","year":"2020","journal-title":"Opt. Express"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2290","DOI":"10.1109\/TCOMM.2020.3046659","article-title":"Deep learning aided robust joint channel classification, channel estimation, and signal detection for underwater optical communication","volume":"69","author":"Lu","year":"2020","journal-title":"IEEE Trans. Commun."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Li, D.-C., Chen, C.-C., Liaw, S.-K., Afifah, S., Sung, J.-Y., and Yeh, C.-H. (2021). Performance evaluation of underwater wireless optical communication system by varying the environmental parameters. Photonics, 8.","DOI":"10.3390\/photonics8030074"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1007\/s00773-020-00724-7","article-title":"Performance studies of MIMO based DCO-OFDM in underwater wireless optical communication systems","volume":"26","author":"Hema","year":"2021","journal-title":"J. Mar. Sci. Technol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"18874","DOI":"10.1364\/OE.453918","article-title":"Modeling and performance analysis of oblique underwater optical communication links considering turbulence effects based on seawater depth layering","volume":"30","author":"Ji","year":"2022","journal-title":"Opt. Express"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3654","DOI":"10.1109\/JLT.2022.3153177","article-title":"Design and implementation of more than 50m real-time underwater wireless optical communication system","volume":"40","author":"Zhou","year":"2022","journal-title":"J. Light. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Sun, K., Li, Y., and Han, Z. (2023). Research on underwater wireless optical communication channel model and Its application. Appl. Sci., 14.","DOI":"10.3390\/app14010206"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Pandey, P., and Aggarwal, M. (2023). Impact of Variable Aperture Area of Transmitter on High-Speed OOK Underwater Visible Light Communication System. OCEANS 2023-Limerick, IEEE.","DOI":"10.1109\/OCEANSLimerick52467.2023.10244611"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1012","DOI":"10.1007\/s11082-024-06879-6","article-title":"Feasibility analysis of line of sight (LOS) underwater wireless optical communications (UWOCs) via link budget","volume":"56","author":"Zayed","year":"2024","journal-title":"Opt. Quantum Electron."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1358","DOI":"10.1109\/OJCOMS.2024.3367457","article-title":"Aqua-sense: Relay-based underwater optical wireless communication for IoUT monitoring","volume":"5","author":"Salman","year":"2024","journal-title":"IEEE Open J. Commun. Soc."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"32570","DOI":"10.1038\/s41598-025-18406-y","article-title":"Performance analysis and optimization of modulation techniques for underwater optical wireless communication in varied aquatic environments","volume":"15","author":"Zayed","year":"2025","journal-title":"Sci. Rep."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1518","DOI":"10.1109\/ACCESS.2016.2552538","article-title":"Underwater optical wireless communication","volume":"4","author":"Kaushal","year":"2016","journal-title":"IEEE Access"},{"key":"ref_32","unstructured":"Jerlov, N.G. (1976). Marine Optics, Elsevier."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Tse, D., and Viswanath, P. (2005). Fundamentals of Wireless Communication, Cambridge University Press.","DOI":"10.1017\/CBO9780511807213"}],"container-title":["Journal of Sensor and Actuator Networks"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2224-2708\/15\/1\/17\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T10:16:38Z","timestamp":1770027398000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2224-2708\/15\/1\/17"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,2]]},"references-count":33,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["jsan15010017"],"URL":"https:\/\/doi.org\/10.3390\/jsan15010017","relation":{},"ISSN":["2224-2708"],"issn-type":[{"value":"2224-2708","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,2]]}}}