Joint optimization of sensing duration and detection threshold for maximizing the spectrum utilization

Sensing-throughput trade-off has been widely discussed in the literature of cognitive radio networks. The constraint of the probability of detection is generally used for the protection of primary users. However, defined detection probability does not fully satisfy the goal of primary user protection. Even in the perfect sensing case, the primary user may appear in between two sensing epochs and suffer interference from the secondary user's transmission. Moreover, fixing detection probability may lead to decrease in the chances of utilization of possibly available spectrum holes. Motivated by the above-mentioned facts, in this paper, we have formulated a new objective function by the name of spectrum utilization, which considers the spectrum used by both primary user and the secondary user. While formulating the objective function, we have also considered the interference caused by the sudden appearance or disappearance of primary user in both perfect and imperfect sensing case, which will be having an impact on effective spectrum utilization. Thereafter, we jointly optimize threshold and sensing duration which can be applied to energy detection based spectrum sensing in cognitive radio models for maximizing the spectrum utilization. Finally, the simulation results are provided to evaluate the performance of the proposed joint optimization.