Adaptive double-threshold based energy detector for spectrum sensing in cognitive radio networks

Abstract

In cognitive radio networks, spectrum sensing is used to sense the unused spectrum in an opportunistic manner. In this paper, we propose an energy detector utilizing adaptive double threshold (ED_ADT) for spectrum sensing, which improves detection performance as well as overcomes sensing failure problem. The detection threshold is made adaptive to the fluctuation of the received signal power in each local detector of secondary user. Numerical results show that proposed ED_ADT scheme outperforms conventional energy detector by 12.8% at –8 dB signal-to-noise ratio (SNR) in terms of probability of detection alarm (P d). While utilizing cooperative spectrum sensing (CSS) with ED_ADT scheme, it is further found that adaptive double threshold improves detection performance around 26.8% and 7.6% as compared to CSS with single threshold and hierarchical with quantization method at –10 dB SNR, respectively, under the case when a small number of sensing nodes are used in spectrum sensing.