Spectrum-Occupancy Aware Cooperative Spectrum Sensing Using Adaptive Detection

In this paper, an efficient adaptive detection scheme is proposed for cognitive radio networks where multiple secondary users (SUs) cooperate to identify idle spectrum bands. Each SU generates a binary local decision, which is then transmitted either directly or via the assistance of intermediate relays to a cognitive radio base station (CRBS), where the global decision is made. The fusion process at the CRBS is performed using the local binary decisions made by the individual SUs. The local binary decisions at the relays and CRBS are regenerated based on dynamic thresholds, which are chosen to minimize the probability of the spectrum sensing error (PSSE) by considering the imbalanced nature of the spectrum occupancy, as well as the reliability of the decisions made by the SUs. The PSSE performance is derived where a closed-form analytical expression is obtained. The analytical results corroborated by Monte Carlo simulation show that using adaptive detection can reduce the PSSE significantly as compared to the conventional detection approach.