Effect of spectrum sensing and transmission duration on spectrum hole utilisation in cognitive radio networks

Abstract

This study presents the trade-off between probability of spectrum hole utilisation (PSHU) and sensing time duration of secondary user (SU) in cognitive radio networks. On the basis of the analytical formulations of PSHU, it is shown that there exist an optimal sensing time duration and the optimal length of time frame for a given mean idle time of primary user (PU). Unlike the existing works, a frame structure of SUs with a fixed length of time frames is considered. The effect of both sensing and transmission time of SUs over PSHU is considered simultaneously. As increasing sensing time duration to improve the probability of detection for PU's presence or absence leads to a reduction in transmission time, which may further decrease PSHU. The numerical and simulation results show that using the optimal sensing time duration (which leads toward the optimal reduction in transmission time) and the optimal length of time frame provides the maximum PSHU.