Performance analysis of hard fusion rules under noise uncertainty at low SNR

Spectrum sensing is a crucial issue in cognitive radio networks for primary user detection. Energy detection is widely makes the detector unreliable due to the varied noise power. In this paper, we take noise uncertainty into consideration for three kinds of hard fusion strategies (OR rule, AND rule, and Majority rule), and compare the sensing performance for these fusion rules to achieve the reliable fusion rule [1] in different networks and different channels (AWGN and Rayleigh). Extensive simulations indicate that AND rule performs the best for most cases over AWGN channels, while OR rule applies to the network with few sensors at low probability of false alarm. However, in Rayleigh channels OR rule is a good choice except the case that noise uncertainty is low and the number of cognitive sensors is large.