University of Connecticut OpenCommons@UConn Doctoral Dissertations University of Connecticut Graduate School 6-24-2013 Communications and Networking in Underwater Acoustic Networked Systems Zhaohui Wang [email protected] Follow this and additional works at:https://opencommons.uconn.edu/dissertations Recommended Citation Wang, Zhaohui, "Communications and Networking in Underwater Acoustic Networked Systems" (2013).Doctoral Dissertations. 134. https://opencommons.uconn.edu/dissertations/134 Communications and Networking in Underwater Acoustic Networked Systems Zhaohui Wang, Ph.D. University of Connecticut, 2013 The Earth is mostly a water planet, with two thirds of its surface covered by water. Exploration of the mysterious water world has never ceased in human history, yet at the time being, less than one percent of this environment has been explored, since it cannot be probed through satellites nor visited by humans for a long time. Driven by the unprecedented development of wireless communica- tions and networking in terrestrial radio applications, underwater wireless net- worked systems, especially underwater acoustic (UWA) networked systems, are envisioned to revolutionize underwater exploration through providing long-term, continuous and real-time unmanned data acquisition. Nevertheless, a plethora of research issues associated with the UWA networked system have to be identified and addressed before meeting its great potential. Out of a myriad of challenges, UWA communications and networking are the most important components that underpin the system architecture. This thesis aims to identify and address challenges in practical acoustic net- workedsystems. Tailoredtotheorthogonalfrequency-divisionmultiplexing(OFDM) modulation, three research directions are pursued: Zhaohui Wang––University of Connecticut, 2013 Communication techniques for UWA channels with widely separated mul- • tipath clusters: This type of channel exists in many scenarios, such as the deep-sea horizontal communications and underwater broadcasting net- works. Due to the extremely large delay spread and time variation of UWA channels, both interblock and intercarrier interferences are present in the received signal. Advanced receiver processing algorithms are investigated to address the above interferences and recover the transmitted information. External interference cancellation in UWA OFDM: Despite rich interfer- • ence in UWA environments, few studies are available for interference miti- gation in UWA communications and networking. In this vein, we propose a parameterized interference cancellation approach to mitigate an external interference from OFDM transmissions, which is shown applicable to other kinds of interferences in UWA networked systems. Asynchronous multiuser OFDM reception: Multiuser communication is an • effective methodology to increase spectral efficiency. Due to the large signal propagation delay in water, signals from multiple users could be severely misaligned at receivers. By introducing the concepts of overlapped truncation and interference aggregation, we convert the asynchronous mul- tiuser problem to a quasi-synchronous multiuser problem with interference contamination, which therefore can be solved through a traditional quasi- synchronous multiuser receiver equipped with interference cancellation. Zhaohui Wang––University of Connecticut, 2013 Proposed solutions in the above research directions are validated using both sim- ulated and field experimental data sets. Communications and Networking in Underwater Acoustic Networked Systems Zhaohui Wang B.S., Beijing University of Chemical Technology, Beijing, China, 2006 M.S., Graduate University, Chinese Academy of Sciences, Beijing, China, 2009 A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy at the University of Connecticut 2013 Copyright by Zhaohui Wang 2013 To my parents iii ACKNOWLEDGEMENTS I would like to express my heartfelt gratitude to my major advisor, Professor ShengliZhou, whohasbeenamentor, colleagueandfriend. Hisguidance, support and encouragement have made this a thoughtful and rewarding journey. His sharp insight, clear mindset and down-to-earth attitude toward research have set anexample ofacademicperfection, fromwhich Iwill continue tobenefit infuture. I would like to thank Professor Peter K. Willett, Professor Yaakov Bar- Shalom, Professor Jun-Hong Cui, Professor Krishna Pattipati, Professor Peter Luh, Professor Bing Wang and Professor Zhijie Shi for their excellent guidance over the years. It was my great pleasure working with such intelligent and inspi- rational professors. I would like to thank Professor Zhengdao Wang from Iowa State University for his valuable suggestions on my work. I would like to thank Dr. Josko Catipovic from the Navy Undersea Warfare Center for insightful dis- cussions on research problems and his help on collecting experimental data sets from the AUTEC environment. I would like to thank Dr. James Preisig, Mr. Lee Freitag and their teams from the Woods Hole Oceanographic Institution for their help on experimental data collection. I would also like to thank Dr. Jianzhong Huang, Dr. Jie Huang, Dr. Xiufeng Song, Dr. Ramona Georgescu, and Dr. Chris- tian R. Berger for their help on my research. iv I would like to extend my gratitude to my colleagues, Lei Wan, Yi Huang, Sora Choi, Xiaoka Xu, Hao Zhou, Patrick Carroll, Jun Liu, Yibo Zhu, Haining Mo, Lina Pu, Yu Luo, Li Wei, Huizhong Gao, Yougan Chen, Haixin Sun, Yuzhi Zhang, Shuo Zhang, Xin Tian, Ting Yuan, Djedjiga Belfadel, David Crouse and Dave Zhao for their support, feedback, and friendship. Last but not least, I give my deepest gratitude to my parents, Yongcheng Wang and Jiuqin Sun, and my brother Lei Wang for their love, understanding, support and encouragement, and for letting me pursue my dreams far fromhome. They have been my continuous inspiration to accomplish my doctorate program. To my family, I dedicate this dissertation. v