Understanding the role of multi-rate retry mechanism for effective rate control in 802.11 wireless LANs

We consider the multi-rate retry (MRR) capability provided by current 802.11 implementations and carry out simulation-based study of its impact on performance with state-of- the-art rate control mechanisms in typical indoor wireless LAN scenarios. We find that MRR is more effective in non-congested environments, necessitating the need for a mechanism to differentiate between congested and non-congested situations to better exploit the MRR capability. We also observe that decoupling the long-term rate adaptation algorithm from the MRR mechanism is key to fully realizing the benefits of MRR.