Admission region for multimedia services in IEEE 802.11e systems

The work presents the simulation analysis aimed at evaluating the admission region of a IEEE 802.11 e draft 4.0 standard, adopting the EDCF (enhanced distributed coordination function) access control mechanism. In particular, the study gives an estimate of the number of QoS aware services, namely videoconference and voice over IP (VoIP), that can be admitted to the transport service offered by the EDCF, while their QoS requirements are satisfied. In the study, the ideal radio channel model is assumed. Furthermore, the traffic sources are obtained from traffic data acquired by means of measurement campaigns made during emulation of VoIP and videoconference services, based respectively on G.723.1 and H.261 codec. Finally the QoS parameters experienced by a mix of VoIP, videoconference and TCP traffic transmitted according to the EDCF mechanism are compared with those obtained when the DCF mechanism is adopted. The result of this comparison clearly highlights the efficiency in the traffic differentiation of the EDCF mechanism.