A Renewal Theory Based Analytical Model for Multi-Channel Random Access in IEEE 802.11ac/ax

To support bandwidth-intensive services such as virtual reality video applications, next generation WLANs will allow users to transmit over multiple channels for high data rate transmissions. In this paper, an analytical model is developed to study the performance of the dynamic channel bonding in IEEE 802.11ac, and non-contiguous channel aggregation in IEEE 802.11ax, with coexisting legacy single channel users. By modeling the transmissions of single channel and multi-channel users with and without channel bonding as a two-level renewal process, the bonding probability of multi-channel users, along with the throughput of different users in each channel, are derived. Our analysis shows that multi-channel users can boost their throughput at the cost of degraded throughput of legacy users. Furthermore, it is shown that 802.11ax provides higher spectrum utilization compared to 802.11ac, while 802.11ac provides a friendlier coexistence with single channel users. Based on the analysis, a heuristic algorithm for primary channel selection is further proposed to maximize the throughput of multi-channel users. Extensive simulations using NS-3 validate the analysis and demonstrate the efficiency of the proposed channel selection algorithm.