Adaptive Spectrum Distribution in WLANs

The IEEE 802.11 standard statically channelizes the wide spectrum into smaller channels of equal width, and classically, each access point is assigned one of these channels to operate on. While an intelligent channel assignment for interfering APs can provide better network performance than just any arbitrary channel assignment, still recent work shows that even far better performance can be achieved if the fixed 802.11 channels are not used and instead the channel width and central frequency for each AP is adapted, based upon the traffic load at each AP in the network. However, the existing work for dynamic distribution of spectrum amongst APs, provides non-overlapping channels to interfering APs, which can cause loss of spectral reuse opportunities. In this paper, we propose a new dynamic spectrum distribution technique in infrastructured wireless LANs, that exploits spectrum reuse opportunities and allows overlap between channels provided to interfering APs. Our technique achieves two goals: 1) max-min fairness amongst flows in the network and 2) high network throughput. Finally, we evaluate the performance of our technique, via simulations, and present its superiority when compared to single-channel 802.11-like DCF, classic fixed channelization and the state-of-the-art dynamic spectrum distribution technique for WLANs.