Date Added: May 2011
The authors provide the first rigorous analysis of proportional fairness in 802.11 WLANs. This analysis corrects prior approximate studies. They show that there exists a unique proportional fair rate allocation and completely characterize the allocation in terms of a new air-time quantity, the total air-time. Proportional fairness has been the subject of considerable attention in the literature on multi-rate 802.11 WLANs since it can be used to address the performance "Anomaly" in a principled manner and is closely related to so-called time-based fairness. Well established utility fairness techniques from wired networks cannot be directly applied to random access CSMA/CA wireless networks due to the presence of collision losses and the coupling of station transmissions via carrier sense.