Buffer Allocation Management for Improving TCP Fairness in IEEE 802.11 WLANs

TCP fairness is an important issue in WLAN because the wireless channel is shared by all wireless nodes. Due to TCP-unfriendly nature of ACK packet, the network service is biased toward the uplink TCP flow and the downlink TCP flow tends to starve. In this paper, a buffer allocation algorithm on the downlink buffer of the Access Point (AP) is proposed to improve the fairness among uplink and downlink TCP flows. The proposed algorithm limits the TCP-unfriendly behavior of ACK packets by adjusting the maximum size of buffer allocated for ACK packets. Analysis and simulation results show that the proposed solution not only improves the fairness greatly, but also achieves higher total network goodput.