vahid jamali - k.n.toosi university of technology
mahmoud ahmadian
seyedhamid safavi
mehrdad ardebilipour

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 their secondary network utilizes the same primary band to send their observations data fusion toward the fusion center while by controlling the trandmit power the secondary users it is assured that the outage probability of the primary transmission remains below a prdfined threshold.