Priority-based Resource Reservation Mechanism for Uplink Multi-user Transmission in IEEE 802.11ax Networks

IEEE 802.11ax adopts orthogonal frequency division multiple access (OFDMA) technology in the physical layer to address the efficiency degradation problem as the device density increases. OFDMA allows multiple devices to transmit or receive the data from an access point (AP) at the same time by sharing available bandwidth. However, the success rate of random access is highly dependent on the number of devices. Transmission collisions will cause devices with high-priority data to experience higher transmission delays. In this paper, we design a multi-queue priority scheduler with timeslot reservation, which improves the efficiency of random access. Devices with high-priority data have a higher transmission probability. To achieve the expected access proportion, the scheduler can change the average access times of different priority devices based on the access rules and the number of queues. Thus, the proposed mechanism can not only meet the delay requirements of high-priority data but also avoid the starvation problem of low-priority data. Mathematics and simulations show that our mechanism has better throughput and delay performance in IEEE 802.11ax networks.