Spectrum sensing in public safety applications: The 2-D LAD ACC method

Public safety communications (PSC) are invaluable in safety critical scenarios such as floods or earthquakes when commercial communication systems fall down. Cognitive radio (CR) approach that is independent of other communication systems provides flexibility and certainty. One of the key issues is to reliably find unused radio channels also in the situations when there is no a priori information about possible other users. In this paper, we propose using the two-dimensional localization algorithm based on double-thresholding with adjacent cluster combining (2-D LAD ACC) method for detecting free channels. It is low-complex, blind and able to operate in any frequency area. This paper applies the 2-D LAD ACC method for real-world channel measurement data for the first time. The indoor measurements at WLAN bands verify that the 2-D LAD ACC method is able to operate in the real-life situation.