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Integrated quality-of-service differentiation over IEEE 802.11 wireless LANs

<06>Existing medium-access-control mechanism employed in IEEE802.11 WLAN distributed-coordination-function (DCF) does not support quality-of-service (QoS) differentiation. Enhanced-distributed-channel-access (EDCA) in IEEE802.11e only supports delay differentiation. In this paper we have developed a new approach (EDCA+) to enhance QoS in WLANs. Bandwidth, delay, jitter differentiation are achieved by distinguishing minimum contention window, maximum backoff stage or persistent factor and packet-loss rate differentiation by distinguishing retry limit. Our analytical models allow the analysis of EDCA+ performance in terms of throughput, bandwidth, delay, jitter, packet-loss rate. For the first time we have shown EDCA+ performs significantly better than DCF and EDCA in ensuring integrated QoS.