An apparatus for wireless communications, including a processing system configured to receive requests for a spatial division multiplexed transmission from a plurality of nodes over a multiple access medium; and initiate the spatial division multiplexed transmission based on a metric related to one or more of the nodes, is disclosed. Another apparatus for wireless communications, including a processing system configured to generate data belonging to an access class having contention parameters; and precode at least a portion of the data for transmission over a spatial stream and enter into post backoff following the spatial stream transmission, is also disclosed. Methods for using the apparatuses are also disclosed.