The IEEE 802.11n wireless local-area network (WLAN) has been widely deployed at every place around the world for the Internet access services. In WLAN, the throughput unfairness problem appears among concurrently communicating hosts due to their signal strength differences when the distances to access-points (APs) are different. Previously, to achieve fair network services among users, we have studied the method of controlling the packet transmission delay at one AP using PI controller. However, it cannot be applied to multiple APs that are common in WLAN. In this paper, we propose a throughput fairness control method of applying traffic shaping at the APs to provide the fair throughput among concurrently communicating hosts with multiple APs. For evaluations, we implement the testbed system using Raspberry Pi for APs and conduct extensive experiments in six topologies with up to four APs. The results show that the throughput of every host is similar to each other in any topology, which confirms the effectiveness of the proposal.
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