Hard combining based energy efficient spectrum sensing in cognitive radio network

In traditional hard combining cooperative detection strategy, the fusion center (FC) determines whether the spectrum of interest is idle or occupied by primary user (PU) after collecting the decisions from all secondary users (SUs) involved. This paper introduces two kinds of simple and computationally efficient spectrum sensing schemes with which the final decision at the FC can be reached faster. Specifically, we proposed hard combining based sequential detection and ordered transmission schemes under different signal-to-noise ratio (SNR) distribution assumptions. In these schemes, the FC performs hypothesis test each time after it receiving one decision from a SU until the final decision can be made reliably. The simulation results show the proposed techniques can significantly reduce the number of data required in identification of the spectrum hole while achieving the same error probability compared with traditional methods.