Assessing the IEEE 802.11e QoS effectiveness in multi-hop indoor scenarios

The IEEE 802.11e technology is receiving much interest due to the enhancements offered to wireless local area networks in terms of QoS. Other application fields for this technology are wireless ad hoc networks, wireless mesh networks, and vehicular ad hoc networks. In the literature, most of the research works available focusing on the IEEE 802.11e technology offer simulation results alone, being hard to find empirical results of implementations that prove its effectiveness in realistic scenarios. Additionally, we consider that studies of IEEE 802.11e based on simulation platforms have not been thoroughly validated using real-life results. In this work we analyze the performance of the IEEE 802.11e technology in real multi-hop ad hoc networks. With this purpose we first we devise a set of experiments where we compare the results obtained on a small testbed to those from the ns-2 simulation platform. A significant consistency in terms of overall trends is found, although remarkable differences can be appreciated in terms of both delay and throughput results. Afterward we proceed with a full deployment of IEEE 802.11e enabled stations throughout the floor of an university building, performing several experiments using both static and dynamic routing. Experimental results show that QoS can be reasonably sustained for both voice and video traffic in multi-hop ad hoc networks, although dynamic routing protocols can hinder performance by provoking frequent on–off connectivity problems.