Designing three dimensional block codes for MIMO communication systems

A major technical challenge in wireless communications is to improve the error performance of the system while maintaining low implementation complexity. A wireless communication channel generally offers multiple sources of diversity such as space, frequency, time, channel propagation state, polarization, etc. However, most existing diversity techniques exploit only one of the various diversity resources of a wireless channel. In this dissertation, we consider the design of a block code for MIMO wireless systems that is capable of jointly extracting multiple sources of diversity therefore improving the error performance further while keeping the decoding complexity low. The proposed coding scheme is referred to as 3D block code because it essentially codes across three dimensions of the channel. We provide general design guidelines and discuss the diversity and coding gain of the 3D block code. This simple scheme achieves full diversity and offers rate-one transmission. The 3D block code can be applied to any wireless communication channel that offers two sources of diversity. Examples of such systems include MIMO-OFDM and Reconfigurable MIMO systems, that are analyzed in this dissertation.;Following the design guidelines of the 3D block code, we design Space-Frequency and Space-Time-Frequency block codes for MIMO-OFDM that outperform the existing block codes in terms of performance and decoding complexity. These coding schemes are referred to as Quasi-Orthogonal Space-Frequency and Quasi-Orthogonal Space-Time-Frequency block codes due to the quasi-orthogonal structure of the underlying code.;Although MIMO techniques are considered in the 3G standards, due to implementation cost and space constraint employing multiple antennas are not generally affordable in mobile handsets. Reconfigurable antennas offer a promising solution for deployment in handset devices. We propose and fully analyze a MIMO system based on reconfigurable antennas. We derive the maximum diversity gain offered by a reconfigurable MIMO system. Moreover, we propose schemes on how to extract such maximum diversity gains when the transmitter, the receiver, or both side of the communication system employ reconfigurable antennas. We prove that our proposed transmission schemes offer full diversity and achieve rate one. Furthermore, tradeoffs of the system in terms of decoding delay, decoding complexity and performance are discussed. To provide a more realistic measure of our proposed schemes, we perform simulations based on various reconfigurable antennas, namely the ORIOL and PIXEL antennas. We also take into account the effects of switching delays of the MEMS switches of reconfigurable antennas in the performance of our schemes and quantify the incurred loss in the signal-to-noise ratio.