Optimal Configuration of 802.11e EDCA for Real-Time and Data Traffic

Abstract — The EDCA mechanism of the 802.11e standard provides QoS support through service differentiation, by using different MAC parameters for different stations. The configu-ration of these parameters, however, is still an open research challenge, as the standard provides only a set of fixed recom-mended values which do not take into account the current WLAN conditions and therefore lead to suboptimal performance. In this paper we propose a novel algorithm for EDCA that, given the throughput and delay requirements of the stations present in the WLAN, computes the optimal configuration of the EDCA parameters. We first present a throughput and delay analysis that provides the mathematical foundation upon which our algorithm is based. This analysis is validated through simulations of different traffic sources (both data and real-time) and EDCA configurations. We then propose a mechanism to derive the optimal configuration of the EDCA parameters given a set of performance criteria for throughput and delay. We assess the effectiveness of the configuration provided by our algorithm by comparing it against i) the recommended values by the standard, ii) the results from an exhaustive search over the parameter space, and iii) previous configuration proposals, both standard and non-standard compliant. Results show that our configuration outperforms all other approaches. I