HCAAC - Hybrid Channel Access by Admission and Contention in Wi-Fi Networks

With the rapid growth of machine-to-machine (M2M) communications, the network infrastructure must urgently support the coexistence of real-time applications (RTA) and non-RTA. Different techniques have been developed for this purpose in wired and cellular networks, while Wi-Fi networks have received less attention. This paper proposes a hybrid channel access by admission and contention (HCAAC) scheme to achieve the coexistence of RTA and non-RTA in Wi-Fi networks. An admission-based channel access scheme is developed for RTA to guarantee a short latency by enhancing the access efficiency of RTA packets. In addition, the non-RTA performance deterioration caused by the transmission of RTA packets can be alleviated by improving the retransmission efficiency of non-RTA packets. To optimize the performance of the proposed HCAAC scheme, we analyze its performance with a two-stage solution and demonstrate how to tune the backoff parameters to minimize RTA packet latency. It is revealed that the optimal backoff parameters depend solely on the number of stations and the packet arrival rate of RTA packets. Simulations demonstrate that with the proposed HCAAC scheme, RTA packets can achieve low latency without degrading the performance of non-RTA packets, shedding light on the design of the next generation of Wi-Fi standards.