A QoS scheme for digital home applications in IEEE 802.11e wireless LANs

Since the legacy IEEE 802.11 standard offers inadequate QoS support, IEEE 802.11e was proposed to provide QoS support for multimedia applications. However, for the enhanced distributed channel access (EDCA) of IEEE 802.11e, when a channel is occupied with high priority traffic, low priority traffic may suffer starvation due to its little chance of contending for the channel. The starvation of low priority traffic may result in failure of these digital home applications, which is unacceptable. DDRR was proposed to achieve this goal; however, it cannot be adapted to traffic condition dynamically. In this paper, we propose a QoS scheme, called starvation prevention for low-priority traffic (SPLPT), for digital home applications in IEEE 802.11e WLANs. SPLPT prevents starvation of low priority traffic by providing adequate contention-free channel access with its compensation procedure for starving traffic (CPST) when starvation is about to occur; and it has the same behavior as EDCA when the CPST is not activated. SPLPT integrates both EDCA and HCCA (HCF controlled channel access) of the IEEE 802.11e to provide high throughput performance as well as starvation prevention, and it is fully compatible to IEEE 802.11e. Simulation results have shown that when the WLAN is heavily loaded with high priority traffic, SPLPT shortens the IMAC delay of low priority traffic by 3.9 and 5.1 times, respectively, compared to EDCA and DDRR. In addition, the throughput of low priority traffic is raised up from 0% to 5% of the maximum throughput to avoid starvation