An effective use of spectrum usage estimation for IEEE 802.22 networks

IEEE 802.22 networks consist of base stations and consumer premise equipments (CPEs) where the base station in each cell opportunistically accesses and allocates (uplink and downlink) channels to all the CPEs in its cell. Information on white space (unused primary channels) availability is reported by the CPEs to the base stations. Thus, a base station's effectiveness to allocate channels are based on its ability to gauge the spectrum usage at various locations. In this paper, we propose a channel usage estimation framework where a base station uses the spectrum reports from other neighboring base stations to estimate the spectrum usage scenario at any arbitrary location within its cell. Our estimation framework is based on Shepard's interpolation technique for irregular points. We propose a channel allocation scheme that minimizes interference among CPEs and maximizes white space utilization. Through simulation experiments, we demonstrate the accuracy of the estimation technique, utilization of the available spectrum, and efficiency of allocation scheme. We also show that our scheme achieves very low false positives and no false negatives. Finally, we show that the optimal number of base stations that need to be consulted is in accordance with Shepard's bounds 1 .