A study of transmit and receive antenna diversity techniques for communication systems

In this dissertation we study two aspects of spatial diversity techniques used in surveillance systems and wireless communication systems. System performance can be increased significantly by using several receive antennas and/or several transmit antennas and exploiting the inherent spatial diversity of the communication channels.; Multisensor surveillance systems are composed of several sensors spread over a geographic area. Such an arrangement allows increased coverage area and reliability compared to a single sensor system. Distributed detection schemes are studied which allow decreased communication bandwidth in comparison with centralized processing. The focus of our study is to specify necessary conditions for the design of optimum distributed detection schemes under Neyman-Pearson (NP) criterion. An efficient algorithm based on these necessary conditions is proposed for finding NP-optimum distributed detection schemes.; Some recent studies show that the bottleneck of capacity in wireless communication systems may be alleviated by employing multiple transmit and receive antennas. Space-time coding is one of the approaches that can realize the increased capacity promised by such a multiple antenna system. Space-time coding relies on multiple coded transmissions that are combined with appropriate signal processing at the receiver to provide both coding gain and diversity gain. In our study, space-time convolutional codes which provide maximum diversity gain and maximum coding gain are found for some practical cases using a new search procedure. We also propose design criteria for robust space-time block codes for rapid fading channels. The procedure we proposed simplifies the code design by allowing us to construct space-time block codes from existing algebraic codes. Finally, we study the use of low rate space-time codes in a cellular system where the capacity is reduced in the presence of cochannel interference. Rate adaptation is discussed which takes advantage of both high rate and low rate space-time codes.