A Cross-Layer Approach for Per-Station Fairness in TCP over WLANs

In this paper, we investigate the issue of per-station fairness in TCP over IEEE 802.11-compliant wireless local area networks (WLANs), especially in Wi-Fi hot spots. It is asserted that the hot spot suffers from the unfairness among wireless stations in exploiting the wireless medium. The source of this unfairness is analyzed from two aspects, TCP-induced asymmetry and MACinduced asymmetry; the former causes TCP congestion control with a cumulative acknowledgment mechanism to prefer the wireless sending stations to the wireless receiving stations, whereas the later exacerbates the unfairness problem in the hot spots. By investigating the interaction between TCP congestion control and MAC contention control, we reveal that, even when a wireless station has a sufficiently large amount of traffic to send, it cannot always participate in the competition to access the wireless medium since the attempts to access the medium in the IEEE 802.11 MAC layer are controlled by the TCP congestion c...

• Type: Journal
• Year: 2008
• Where: TMC
• Authors: Eun-Chan Park, Dong-Young Kim, Hwangnam Kim, Chong-Ho Choi
• Keywords: Hot Spots, Per-station Fairness, TMC 2008, Wireless