Enhancements to IEEE 802.11 DCF collision avoidance based on MIMO Adaptive Spatial Channels Sharing

In this paper, the IEEE 802.11 Distributed Coordination Function (DCF) collision avoidance mechanism of Wireless Local Area Networks (WLANs) is enhanced based on Adaptive Spatial Channels Sharing (ASCsS) of Multiple Inputs Multiple Outputs (MIMO) transmission systems. Simply, instead of accessing the medium using all the spatial channels, to avoid collision the contending nodes use an optimal subset of the available spatial channels during the medium contention period. As the total number of concurrent used spatial channels is fewer than or equal to the spatial degree-of-freedom, receivers can still decode the transmitted singles of multiple medium access contenders. The performance of the ASCsS scheme demonstrates that the scheme further reduces medium access collisions and boosts the medium utilization.