Distributed Interference-Aware Scheduling Schemes for High-Density WLAN

The increasing density of WLAN devices induces severe inter-cell interference problem in nowadays WLAN system. The traditional distributed coordination function (DCF) mechanism in IEEE 802.11 protocol was designed for the avoidance of intra-cell collision, but the inter-cell interference cannot be alleviated by merely increasing the backoff time. Multi-cell scheduling mechanism allocates orthogonal resource to the clients interfering with each other and can efficiently alleviate the interference problem. However, most of the current scheduling schemes are formulated as an optimization problem, the implementation of which requires abundant inter-cell information exchange and the scalability cannot be guaranteed. In this paper, three completely distributed interference-aware multi-cell scheduling schemes are proposed, where the packet loss due to interference is utilized as the scheduling criterion. A stochastic approximation method is utilized to guarantee the system fairness also in the distributed manner. Simulation results show that the proposed scheduling schemes can significantly enhance the overall throughput while guarantee the fairness of the high density WLAN systems.