An optimal cooperative spectrum sensing strategy with exponential primary link traffic

In this paper, we investigate the optimal sensing settings for a cognitive radio (CR) network consisting a number of CR users and a fusion center (FC). Our objective is to maximize the channel utilization under the constraint that the signals from the primary user (PU) are sufficiently protected. We focus on the utilization of the channel in which PUs dynamically enter the network with burst nature. Thus, we apply the average error probability (AEP) as the metric of channel utilization. Moreover, in order to protect the PU signal from being interfered, the missing detection probability is applied as the constraint function. Assuming that counting rules are utilized in the FC, we derive the false alarm probability, the missing detection probability, and the AEP in the maximum a posteriori (MAP) fashion. Then, after proving the monotonic properties of the objective function and the constraint function, we propose an efficient algorithm named Algorithm I that can derive the optimal settings for maximizing the channel utilization. Moreover, a simplified algorithm named Algorithm II is also proposed to minimize the AEP, supposing that perfect synchronization exists between the CR users and the PU. Finally, we show our numerical results and compare our optimal results with those found by exhaustive searches. We conclude that our Algorithm I produces optimal results very close to those found by exhaustive searches. Performance comparison between Algorithms I and II is also provided in terms of the AEP and the probability of missing detection. Copyright © 2012 John Wiley & Sons, Ltd