Auto bit rate adaptation with transmission failure diagnosis for WLANs

This paper proposes a bit rate adaptation scheme based on frame transmission statistics. The bit adaptation scheme judiciously exploits the fragmentation mechanism in the IEEE 802.11 to accurately diagnose the cause of a frame transmission failure and accordingly adjusts the frame delivery statistics. We analytically prove that the fragmentation mechanism incurs less overhead and is more effective than the use of RTS/CTS for rate adaptation in a collisions dominated environments. We implemented and evaluated this scheme and four other recent and representative rate adaptations schemes on a Linux based testbed. We also discuss some anomalies plaguing these rate adaptation schemes observed while implementing them. With extensive experiments, we observe that these rate adaptation schemes have strengths and weaknesses under different scenarios, although our scheme performs very well in most of cases.