Selective Polling and Controlled Contention Based WLAN MAC Scheme for Low-Latency Applications

A novel medium access control scheme is proposed and investigated for central coordinated wireless local area networks to support future low-latency applications. The scheme divides each beacon interval into multiple service cycles, and each service cycle is composed of a polling period (PP) and a contention period (CP). By polling stations according to their latest channel accessing times during each PP and properly assigning backoff count for each station during each CP, the proposed scheme reduces the resource waste caused by polling empty stations and collisions, thereby achieving low-latency performance. In each service cycle, the number of stations to poll during the PP is calculated based on station empty probability, and the backoff count assigned to a station that has not been polled during the PP is unique and relatively small. Our simulation results show that the proposed scheme reduces uplink latency effectively, and can afford more traffic under the 0.5 ms uplink latency constraint compared to the conventional schemes.