Analysis of IEEE 802.11n network Access Categories in EDCA non-saturated networks

In recent years demand for high data rate amongst internet users has increased due to the use of real time data services such as video and voice conferencing. The IEEE 802.11n standard is an advancement from the previous a,b and g versions. Its design goal is to increase data rate, and maintain compatibility with the previous versions. The IEEE 802.11n standard introduces improvements at both the PHY and MAC layers. This standard still adopts the EDCA and HCCA mechanism used for enhancing QoS in the network by assigning priorities to different classes of data called Access Categories (ACs). In this paper we compute a theoretical throughput model for 4 different stations transmitting separate ACs in non saturated conditions. Networks with non saturated conditions find real applications in WSN and WiFi enterprises. We then perform a practical experimentation with 4 different nodes and compare the throughput results with the theoretical one. Based on the comparison, we determine the fairness linked with the QoS mechanism. The comparative throughput performance indicates that the analytical results compare well with the practical experimental results considering non saturated ACs.