A enhanced HDCF scheme for solving the uplink and downlink imbalanced link problem in WLANs

The current IEEE 802.11 Distributed Coordination Function (DCF) that provides equal medium access probability to all transmitters suffers from uplink and downlink imbalanced link problem when operating in the infrastructure mode. Therefore, this paper proposes an Enhanced High-performance Distributed Coordination Function (EHDCF) to mitigate this imbalanced link problem. In EHDCF, the current transmitting station selects the access point (AP) with higher probability and the wireless stations with lower probability as the next transmitter to improve the downlink throughput. Simulation results show that EHDCF not only provides fair bandwidth sharing for uplink and downlink traffic but also yields a significant improvement in the network throughput.