A Cross-Layer Two-Stage Scheduler for Wireless LANs

In this paper, a cross-layer scheduler for wireless LAN access points is introduced which includes a MAC and a PHY layer stage. For the MAC scheduler, both a simple round-robin scheme and an adaptive scheme which considers both the queue length and the packet lifetimes of each flow are considered. The MAC scheduler hands over a list with the most important packets to the PHY scheduler, which selects one or more packets according to the channel capacity available for the respective destination stations. It is shown that the combination of the MAC and the PHY layer scheduler increases the throughput while the delay is reduced. Fairness is supported in the way that the performance is enhanced not only for the entire system, but also for the individual flows.