How Many Channels Should Be Sensend in Cognitive Radio Networks?: An Energy Efficiency Perspective

Abstract

In cognitive radio network (CRN), multichannel spectrum sensing can bring cognitive users more spectrum opportunities. Immediately, how to perform spectrum sensing turns into an interesting question. To find the answer, we focus on sequential multichannel sensing from a perspective of maximizing the energy efficiency (EE) of CRN in this paper. The EE of CRN is firstly modeled as the mean of throughput-to-power ratio. Based on the model, an optimization problem is further set up to explore the effects of the number of sensing channels on the EE of CRN. Theoretical and simulated results finally indicate that the number of sensing channels has a tiny effect on the EE of CRN in the case that sequential channel sensing and instant channel access once finding an idle channel. However, the more channels are sensed sequentially, the larger throughput achieves. Our results may make some insights on efficient MAC frame design.