Analysis and Design of Diversity Techniques for Terrestrial and Underwater Acoustic Communications

Since the early 1880’s, wireless broadband communications have been growing at explosive rates. While the personal communication systems have almost exhausted the spectrum, higher and higher data rates are required to support the ever demanding wireless services. Recently, to improve the spectral efficiency, diversity gains, and interference and power management for wireless multimedia and internet services, by combining the signals at both ends and effectively creating multiple parallel spatial data pipes, the multiple-input multiple-output (MIMO) technology has become a convenient framework. Motivated by these practical concerns, this thesis addresses the analysis and design of diversity techniques for terrestrial and underwater acoustic communication channels, in two parts. Part I studies novel relay selection strategies and diversity techniques for single carrier frequency domain equalization (SC-FDE) multi-relay cooperative networks, considering maximum-likelihood (ML) and minimum mean-square error (MMSE) receivers. We further extend our analysis to two-way relaying (TWR) networks, while incorporating different power control techniques. Building on our results on the diversity and error performance of the single relay and TWR cooperative systems, we extend our analysis to design of MMSE-based optimum beamforming matrices at user and relay terminals in a multi-user, multi-antenna TWR cooperative system. We further present a joint user-relay antenna selection algorithm by applying the estimation of distribution algorithm (EDA). The final contribution of the first part of this thesis is to extend our analysis to large relay networks and address the prohibitive computational and implementation complexity cost of the exhaustive search algorithms for joint transceiver/relay beamforming matrix design in large amplify-and-forward (AF) MIMO TWR networks, while incorporating the orthogonal matching pursuit (OMP) algorithm. The second part of this thesis focuses on the performance of differentially encoded space-time and space-frequency block coding techniques for terrestrial and underwater communication channels.