An Uplink Medium Access Protocol with SDMA Support for Multiple-Antenna WLANs

In this paper, we propose a contention based uplink medium access control (MAC) protocol design for wireless local area networks (WLANs) with spatial division multiple access (SDMA) support. Our protocol does not require sophisticated smart antenna equipments, and it can be implemented in simple omni-directional multiple-antenna WLANs. Different from the super-frame based approaches, the proposed one is a pure contention based MAC protocol and can be easily implemented into standard 802.11 systems with slight modifications. By jointly considering the the physical and the MAC layer situations, dynamic system parameter adjustment is designed to enhance throughput and protocol efficiency. In addition, our protocol provides interface for user scheduling, which makes it more extensible. Simulation results show that our scheme can achieve high network throughput, and discussions regarding different system factors are also included.