Cooperative spectrum sensing in cognitive radio networks under primary outage constraint

In cognitive radio, the aim of the secondary network is to collaboratively determine the presence of the primary user. In such a cooperative scheme, the secondary users firstly attempt to observe the primary band in the observation phase and then, in the reporting phase, transmit their observation to the fusion center where the final decision about the occupancy of primary channel is obtained. Most of the previous work assumed a control channel for the reporting transmission; however, we assume that the secondary network utilizes the same primary band to send their observations (data fusion) toward the fusion center while by controlling the transmit power the secondary users, it is assured that the outage probability of the primary transmission remains below a predefined threshold. In the simulation results, we show that under a given network parameters and a fixed probability of false alarm, there is an optimal observation phase time and number of cooperative secondary users in the proposed cooperative framework which maximize the probability of detection.