Considerations on the multiplexing and diversity tradeoff in IEEE 802.11 networks

Multiple-input multiple-output (MIMO) techniques have received a considerable attention from the research community for their promising performance in faded environments, and particular interest has been given to the physical (PHY) layer implications of the tradeoff between multiplexing and diversity. This study discusses this tradeoff extending the analysis to the medium access control (MAC) layer. To this purpose, a theoretical model for assessing the performance of an 802.11 network that relies on a MIMO-enabled PHY layer is presented. The proposed model characterises the different MIMO systems in terms of their multiplexing gain and bit error rate performance, considering both the diversity gain of the specific MIMO scheme and the impact of the spatial distribution of the nodes. The results compare, from a MAC layer perspective, the benefits of multiplexing and diversity, providing some analytic insights on the tradeoff between increasing the system's reliability and enhancing the data rate of the single link.