A QoS provisioning MAC protocol for IEEE 802.11 WLANs

In this paper we present extended age dependent backoff protocol (EADB), an extension of the age dependent backoff (ADB) proposed to alleviate the delay and jitter of real-time packets. The proposed retransmission scheme considers not only the persistence factors but also the contention window (CW) to reduce collision rate. The persistence factor (PF) is based on the ages of the real-time packets in the transmission queue and the lifetimes of real-time packets. Moreover, we also consider the collision rate that stations experience to adjust the CW. The proposed scheme is able to prevent the degradation the performance of the network caused by setting the CW as the minimum value after successful transmission. Simulation results indicate that the EADB provides the delay, jitter, and drop rate better than ADB.