Wideband spectrum sensing with coexistence of strong and weak primary signals

In cognitive radio applications, the cognitive users should find the spectral hole before it access to the spectrum band licensed to primary users. In order to improve spectral efficiency, wideband spectrum sensing is required for cognitive radio systems. In several environments, some weak primary users (such as microphone signal) are coexisting with strong primary users. In these cases, the weak primary signals may not be detected, and the cognitive user will collide with the primary users. To solve this problem, in this paper, we propose exploiting orthogonal projection technique to sense both the strong and weak primary signals. Finally, the proposed algorithm is verified by numerical simulations.