New prioritization schemes for QoS provisioning in 802.11 wireless networks

Due to the unreliable nature of the wireless medium, provisioning of quality of service (QoS) in wireless LANs is far more complicated than in wired networks. In order to address this challenge, IEEE 802.11e defines a framework for QoS support where packets are prioritized based on their traffic characteristics. In this paper, we propose two new QoS support schemes. One is based on a ldquouser centricrdquo approach and the other on a ldquopacket content basedrdquo approach. The new mechanisms, in addition to the traffic itself, take into consideration the identification of the station that generates the traffic or the content of the traffic. Therefore, they use a second prioritization level on top of the one that is implemented in IEEE 802.11e. In the ldquouser centricrdquo approach, the mechanism defines groups of stations based on their MAC addresses and assigns different priorities to different groups. Under this classification, stations are served based on the prioritization of the group they belong. Among stations with same priority, traffic is scheduled based on the priorities given by 802.11e. On the other hand, in the case of the ldquopacket content basedrdquo approach, the mechanism defines groups of words or phrases with their respective priority. A packet that includes words of a specific group is scheduled based on the priority that the particular content defines. The new schemes are simple yet efficient, since they are adapted to the realistic needs of todaypsilas WiFi networks. In order to evaluate the performance of these proposed schemes, we implement them using open source drivers in a Linux platform. We run experiments in a medium-size testbed. Experimentation results clearly demonstrate the performance superiority of the new schemes, as compared to the legacy IEEE 802.11e.