Efficient Rate Adaptation in Multi-rate 802.11 Networks

Given the multi-rate option in most 802.11 standards, rate adaptation based on dynamic channel condition is crucial to the system performance. This paper presents an efficient rate adaptation mechanism at MAC layer, called ERA, to improve the transport layer throughput. Such scheme raises the transmission rate aggressively, e.g., upon only a few consecutive successful transmissions. In opposite, we reduce the transmission rate more cautiously only when the station encounters severe consecutive frame losses or relatively high loss ratio at MAC layer. ERA also attempts to protect the performance under steady condition without losing the ability to respond to the channel variation quickly. We evaluate ERA using NS-2 simulations and find that it performs better than or at least similarly with many other proposals in various scenarios. ERA is a sender-based method and requires minor modification at sender side only, thus completely standard-compliant and very easy to be implemented and deployed.