摘要：Aggregation with Fragment Retransmission (AFR) is a scheme designed for frame transmission to increase efficiency at the MAC layer throughput. AFR provides a higher throughput compare to Distributed Coordination Function (DCF) scheme. However AFR scheme did not has QoS service function when compared to DCF scheme. DCF scheme already has contention-based QoS service using Enhanced Distributed Coordination Function (EDCA) scheme. In this study, we enhanced the AFR scheme in order to provide the QoS function and called it as AFR plus QoS or abbreviated as AFR+Q. We developed the analytical model to investigate the saturation throughput of AFR+Q scheme. We designed the Markov chain model as state transition of the backoff counter from each Access Category (AC) and we derived the mathematical model of the transmission probability and the saturation throughput of each AC. The simulation result using Matlab shown that the AFR+Q scheme provide higher saturation throughput compared to EDCA scheme. The higher throughput in AFR+Q scheme is produced by the better transmission probability, employed packet fragmentation and aggregate frame schemes.
关键词：IEEE 802.11n; Aggregation with Fragment Retransmission (AFR); Enhanced Distributed Channel Access (EDCA); Aggregation with Fragment Retransmission Plus QoS (AFR+Q); Throughput
