Two-level protection and guarantee for multimedia traffic in IEEE 802.11e distributed WLANs

In order to support multimedia applications such as voice and video over the wireless medium, a contentionbased channel access function, called Enhanced Distributed Channel Access (EDCA), has been developed in the emerging standard IEEE 802.11e. In the EDCA, differentiated channel access is provided for different traffic classes. In this paper, we propose a two-level protection and guarantee mechanism for voice and video traffic in the EDCA-based distributed wireless LANs. In the first-level protection, the existing voice and video flows are protected from the new and other existing voice and video flows via a distributed admission control with tried-and-known and early-protection enhancements. In the second-level protection, the voice and video flows are protected from the best-effort data traffic by adopting frame-based and limit-based data control mechanisms. Performance evaluations are conducted in terms of throughput, delay, transmission limit, number of collisions, and throughput square relative difference. Extensive simulation results demonstrate that the proposed two-level protection and guarantee mechanism is very effective in terms An early version of this paper was presented at IEEE INFOCOM 2004. Y. Xiao ( ) Department of Computer Science, The University of Alabama, 101 Houser Hall, Box 870290, Tuscaloosa, AL 35487-0290, USA e-mail: [email protected] F. H. Li Division of Mathematics and Computer Science, University of South Carolina Upstate e-mail: [email protected] S. Choi School of Electrical Engineering, Seoul National University, Seoul 151-744, Korea e-mail: [email protected] of the protection and guarantee of existing voice and video flows as well as the utilization of the channel capacity.