Decision-Based Cooperative Spectrum Sensing Using Random Medium-Access Sequential Reporting

Sequential reporting has the potential of reducing the duration of the reporting phase of the cooperative spectrum sensing (CSS) schemes, thereby increasing the overall system throughput. In this article, we study decision-based CSS using random medium-access sequential reporting and a K-out-of-M decision rule at the fusion center. Closed-form expressions are derived for the detection and false alarm probabilities as well as the average reporting time of two early termination sequential reporting schemes, assuming a reporting channel shared with the primary user (PU). Furthermore, a heuristic energy-based reporting priority scheme that favors cognitive radio (CR) terminals based on their capacity to detect the PU is proposed. Computer simulations are used to assess the accuracy of the derived expressions and to evaluate the proposed heuristic reporting priority scheme.