Multi-slot spectrum sensing with backward SPRT in cognitive radio networks

In this paper, we propose a novel spectrum sensing technique, called as multi-slot spectrum sensing, to detect spectral holes and to opportunistically use under-utilized frequency bands without causing harmful interference to legacy (primary) networks. The key idea of the proposed sensing scheme is to combine the observations from the past N (N ¿ 2) sensing blocks including the latest one. Specifically, we first establish the detection model with the proposed multi-slot spectrum sensing technique. Then, we deploy the backward sequential probability ratio test (BSPRT) for the established model to detect spectral. Moreover, we evaluate the performances of the proposed scheme in terms of the mean delay for detection and the mean time to false alarm. Compared with the equally combining strategy, which equally combines the statistics of the past multiple sensing blocks, the proposed sensing strategy using BSPRT always performs better, which are verified via the conducted simulations.