Performance analysis of multiuser diversity in MIMO channels

A central feature of mobile wireless networks is the random fading of the channel strengths of the underlying communication links. Traditionally, fading on wireless channels has been viewed as a form of unreliability that must be mitigated in order to achieve reliable data transfer. A new design principle, known as multiuser diversity, rather harnesses the randomness of this fading in a multiuser environment to improve the performance of the overall system. We develop tractable mathematical models for evaluating the average delay, throughput and symbol error probability (SEP) performances of multiuser diversity systems in MIMO channels. Analytical comparisons with the performances of a conventional round-robin scheme like TDMA are then made. Our results show that with multiuser diversity, there is significant reduction in the average delay that user data packets experience in the network, compared to the TDMA system. It is also observed that throughput and SEP performance for a multiuser diversity system improve as the number of users in the cell increase.