AID‐based backoff for throughput enhancement in 802.11ah networks

Summary IEEE 802.11ah is a WiFi standard developed to address requirements associated with the heterogeneous nature of the Internet of Things. It uses the sub‐1 GHz bands to enable long‐range transmissions for low‐power devices. However, long‐range coverage exacerbates the hidden node problem. To mitigate this problem, sectorization and grouping have been proposed by the standard. In this paper, hierarchical clustering and a modified Welsh‐Powell algorithm are combined to create hidden node‐free groups in a sectorized wireless local area network. An analytical model is developed for a deterministic backoff technique that uses association identifiers to set the backoff in order to eliminate collisions. The performance of the deterministic backoff technique is compared with that of existing schemes. Our results show that this approach results in higher throughput and lower latency than other deterministic backoff techniques. This paper proposes an approach to setting the backoff timers of devices in a DCF based 802.11ah network to eliminate collisions in a sectorized network. Simulation results show that if the stations are aware of the hidden nodes in their group and set their backoff timers according to the AIDs of the stations they detect in the group, DCF with AID‐based backoff timers results in a higher normalized throughput and smaller delay compared to the other deterministic backoff techniques.