An Adaptive Medium Access Parameter Prediction Scheme for IEEE 802.11 Real-Time Applications

Abstract

Multimedia communications have experienced an unprecedented growth due mainly to the increase in the content quality and the emergence of smart devices. The demand for these contents is tending towards wireless technologies. However, these transmissions are quite sensitive to network delays. Therefore, ensuring an optimum QoS level becomes of great importance. The IEEE 802.11e amendment was released to address the lack of QoS capabilities in the original IEEE 802.11 standard. Accordingly, the Enhanced Distributed Channel Access (EDCA) function was introduced, allowing it to differentiate traffic streams through a group of Medium Access Control (MAC) parameters. Although EDCA recommends a default configuration for these parameters, it has been proved that it is not optimum in many scenarios. In this work a dynamic prediction scheme for these parameters is presented. This approach ensures an appropriate traffic differentiation while maintaining compatibility with the stations without QoS support. As the APs are the only devices that use this algorithm, no changes are required to current network cards. The results show improvements in both voice and video transmissions, as well as in the QoS level of the network that the proposal achieves with regard to EDCA.

Performance Analysis of Wireless Local Area Network for a High-/Low-Priority Traffic Ratio at Different Numbers of Access Categories

“…To enhance the quality of voice and video transmissions over IEEE 802.11 WLANs, a dynamic prediction scheme is proposed in the paper by Reference [27]. Dynamic adapting of MAC parameters (AIFSN and CW size) optimizes the access to the medium and is composed of several predictive submodels.…”

“…Therefore, by default, the total network throughput is anyway lower than for a network with DCF scheme that does not support priority access and provides only one access category. An analysis of the impact on network throughput of replacing the non-QoS-supported DCF scheme with the QoS-supported EDCA scheme is presented in Reference [27]. The analysis is performed using simulation modeling and shows that providing priority access using EDCA for networks with five or more stations leads to decreasing of total network throughput.…”