Spectrum sensing scheme for overlay cognitive radio networks

Considering the effects of primary user traffic, timing misalignment and multiple arrival and departure issues in a sensing period should be addressed for spectrum sensing in future overlay cognitive radio (CR) networks, such as femtocell networks. To achieve this goal, division of the whole sensing duration into multiple windows is proposed. For each window, a two-step detection scheme, i.e. coarse and fine detection, is proposed to improve the performance of the conventional energy detector (ED) in the overlay CR scenario.