This paper proposes a new protocol called Optimal DCF (O-DCF). Inspired by a sequence of analytic results, O-DCF modifies the rule of adapting CSMA parameters, such as backoff time and transmission length, based on a function of the demand-supply differential of link capacity captured by the local queue length. Unlike clean-slate design, O-DCF is fully compatible with 802.11 hardware, so that it can be easily implemented only with a simple device driver update. Through extensive simulations and real experiments with a 16-node wireless network testbed, we evaluate the performance of O-DCF and show that it achieves near-optimality, and outperforms other competitive ones, such as 802.11 DCF, optimal CSMA, and DiffQ in a wide range of scenarios.
@article{arxiv.1207.3740,
title = {Making 802.11 DCF Optimal: Design, Implementation, and Evaluation},
author = {Jinsung Lee and Yung Yi and Song Chong and Bruno Nardelli and Edward W. Knightly and Mung Chiang},
journal= {arXiv preprint arXiv:1207.3740},
year = {2012}
}