Managing the virtual collision in IEEE 802.11e EDCA

The IEEE 802.11e EDCA is the distributed channel access mechanism introduced by the Quality of Service amendment to the IEEE 802.11 standard. This mechanism introduces differentiation to the channel access. This led to the introduction of the principle of the virtual collision. We study, in this paper, the effect of the virtual collision management as presented by EDCA on its fairness among other properties. We give in this paper a new proposal of collision management for EDCA. The proposal is analyzed by means of a Markov Chain model of EDCA and its effects are discussed. The proposal reduces the unfairness of EDCA.