Class-Based Weighted Window for TCP Fairness in WLANs

The explosive growth of the Internet has extended to the wireless domain. The number of Internet users and mobile devices with wireless Internet access is continuously increasing. However, the network resource is essentially limited, and fair service is a key issue in bandwidth allocation. In this research the focus is on the issue of fairness among stations having different number and direction of flows for different required bandwidth to assure fair channel is fairly shared between wireless nodes in the same class of bandwidth. It is shown that the current WLANs allocate bandwidth unfairly. It is also identified that the cause of this unfairness problem is TCP cumulative ACK mechanism combined with the packet dropping mechanism of AP queue and the irregular space for each station in AP queue. The proposed method allocates converged bandwidth by introducing Class-Based Weighted Window method and it adjusts the TCP window size based on the current conditions of the network and according to their weights. This method works in wireless nodes without requiring any modification in MAC. It can guarantee fair service in terms of throughput among wireless users either they require the same or different bandwidth.