Two-step softened decision for cooperative spectrum sensing in cognitive radio networks

Cognitive radio systems resolve spectrum scarcity problem by exploring, the spectrum allocated but unused by primary users. Spectrum sensing makes a decision on the presence of a PU. In this paper, we propose a two-step sensing scheme by combining non-cooperative and cooperative spectrum sensing. Firstly, non-cooperative spectrum sensing is used, and cooperative spectrum sensing incurs in second, when received energy of a single sensor fails to make decision. Our two-step scheme is combined to a two-step softened combination scheme and achieves a good tradeoff between detection performance and complexity. We derive analysis and conduct simulation for comparison with conventional scheme.