X-EDCA: A cross-layer MAC-centric mechanism for efficient multimedia transmission in congested IEEE 802.11e infrastructure networks

IEEE 802.11e is the indisputable standard for supporting multimedia traffic in modern Wireless Local Area Networks. However, it has been proven incapable of handling efficiently multimedia flows in congested networks. The main reason for this suboptimal behavior roots from the static nature of resource allocation specified in IEEE 802.11e. Dynamic tuning of the MAC parameters has demonstrated a beneficial performance in terms of application efficiency. Nevertheless, it is of great importance that this adaptation takes place by considering the multimedia traffic characteristics. In this paper, a cross-layer MAC-centric mechanism is introduced, under the name X-EDCA. The mechanism is designed to cope with high load situations in IEEE 802.11e wireless infrastructure networks by selectively prioritizing and protecting sensitive multimedia frames. The proposed scheme is evaluated and its effectiveness is proven by means of simulation.