It has been known that spatial correlation imposes negative impacts on multiple antenna communications. Specifically, channel fluctuations by fading are not effectively removed by spatial diversity techniques in correlated channels. Interestingly, these channel fluctuations, however, enhance multiuser diversity gains so that the defects of correlation can be compensated by opportunistic multiuser scheduling. On the other hand, negative influences of spatial correlation on spatial multiplexing schemes are not easily overcome by multiuser diversity gains since spatial multiplexing gains are inherently determined by spatial dimensions of a given channel.
In this dissertation, we quantify the interaction among spatial correlation, spatial diversity, spatial multiplexing, and multiuser diversity. First of all, we analyze and quantify the relations between spatial correlation and multiple antenna techniques with multiuser diversity by the order statistics theory, which provide more intuition for the interactions. Contrary to the asymptotic analysis in preliminary studies, the upper bound from the order statistics theory is rather tighter for smaller number of users so it more accurately quantifies the interaction. Our analysis indicates that the lost diversity gain by spatial correlation can be fully compensated by the multiuser diversity gain if opportunistic multiuser scheduling is employed. As a result, capacities of spatial diversity techniques increase with correlation if multiuser diversity is combined, whereas they have been known to decrease with correlation in a point-to-point communication. However, the reduced dimensions by spatial correlation are not overcome by multiuser diversity gain, hence the capacity of a spatial multiplexing technique decreases with correlation despite opportunistic multiuser scheduling. We additionally investigates the performance of an Alamouti space-time coding based transmit diversity scheme with opportunistic multiuser schedul...