Sequential Cooperative Spectrum Sensing Technique for Cognitive Radio System in Correlated Channel

Cognitive radio is proposed to opportunistically access the spectrum while the licensed user is idle. As a result, spectrum sensing procedure to observe primary user´s existence is vital to cognitive radio. In this paper, we investigate the energy detection based sequential cooperative spectrum sensing technique in time varying channel. By utilizing past local observations from previous sensing slots, cognitive radio nodes can aggregate the current and previously received energy values to improve the detection performance. We explored the moving-average technique using equal and exponential weighting. Simulation results show that this technique provides better detection performance compared to conventional energy detection based cooperative technique. Equal weighting provides the best performance when primary user´s activity is not varying. If the primary users often change states, the proposed exponential weighting approach provides better detection performance.