Fair bandwidth assignment to each terminal by adjusting contention window size in access point

Recently, wireless LANs have been used widely because they are flexible and easy to install. However, there are unfairness problems in wireless LANs, in that a small number of stations (STAs) may obtain a large throughput while other STAs hardly get any bandwidth. One of the unfairness problems occurs between upstream and downstream flows because the access point (AP) and each STA have the same transmission opportunity under CSMA/CA control. In addition, the bandwidth in the wireless network is not shared fairly among STAs. To improve these problems, we proposed a simple method combining the Deficit Round-Robin (DRR) queuing method in the MAC layer and a dynamic contention window control in the MAC layer in the AP. By cross-layer controls, the proposed method can be realized without using information from the TCP/UDP transport protocol. We evaluated the proposed method by computer simulation experiments, and show that the proposed method gives perstation fairness in throughput under multiple TCP/UDP flow communication.