A Throughput Model of IEEE 802.11aa Intra-Access Category Prioritization

In this paper the first saturation throughput model of an IEEE 802.11 network is presented, which includes the intra-access category prioritization introduced in the recently approved IEEE 802.11aa standard. This new feature was proposed to support finer grained prioritization of audio video streams in comparison to the existing Enhanced Distributed Channel Access (EDCA) function. The presented model implements different transmission probabilities for the primary and alternate voice and video queues. Additionally, it includes such features as virtual collision handling, backoff differentiation, and Arbitration Inter-Frame Space differentiation. The presented results show the difference in the operation of IEEE 802.11aa intra-access category prioritization and EDCA inter-access category prioritization. They also allow to derive several novel conclusions.