Cooperative Spectrum Sensing Schemes with the Interference Constraint in Cognitive Radio Networks

In this paper, we propose cooperative spectrum sensing schemes, called decode-and-forward cooperative spectrum sensing (DF-CSS) and amplify-and-forward cooperative spectrum sensing (AF-CSS), in cognitive radio networks. The main goals and features of the proposed cooperative spectrum sensing schemes are as follows. First, we solve the problem of high demand for bandwidth in soft decision scheme using in our proposed schemes. Second, we analyze our proposed cooperative spectrum sensing schemes with detection probability and interference probability, respectively. The simulation results show that the total sensing performance depends not only on interference tolerance level, but also on the relay protocols used in cooperative spectrum sensing schemes. We also prove that higher transmit power of relaying user increases the interference between secondary network and primary network. This conclusion is verified by our simulation results.