Coexisting 802.11a/n and 802.11ac Clients in WLANs: Optimization and Differentiation

The recently released IEEE 802.11ac standard has implemented enhancements including higher maximum transmission rate and larger maximum packet payload length. In wireless local area networks (WLANs) where the latest 802.11ac nodes and the legacy ones coexist, nevertheless, the effects of the enhancements on the data rate performance remain largely unknown. In this paper, we tackle this open problem. The analysis shows that with a growing transmission rate of 802.11ac nodes, the data rates of all the nodes in the network can be improved. If the packet payload length of 802.11ac nodes grows, on the other hand, the data rate of each 802.11ac node increases while the other coexisting nodes' are degraded. To avoid starvation, we further study how to adaptively tune system parameters to optimize the network sum rate under a certain service differentiation requirement among distinct groups. Explicit expressions of the maximum network sum rate and the optimal packet payload lengths are obtained, and verified by simulation results.