QoS and Security Aware Power Allocation Scheme for Wiretap Cognitive Radio Networks

In this paper, we establish a unified Quality-of-Service (QoS) and security provisioning framework for wiretap cognitive radio networks (CRN) by employing the theories of statistical queueing analysis, effective bandwidth, and effective capacity, which can quantitatively characterize the QoS and security requirements. Based on our developed framework, we formulate the nonconvex optimization problem that aims at maximizing the average throughput of secondary user (SU) subject to PU's QoS requirement, CRN's security constraint, as well as SU's average and peak transmit power limitations. By using the techniques of convex hull and probabilistic transmission, we convert the original nonconvex problem to the equivalent convex problem and then obtain the optimal power allocation via Lagrangian method. Simulation results demonstrate the impact of PU's QoS and CRN's security requirements on SU's throughput as well as the advantage of our proposed scheme over the fixed power allocation and the conventional security-based water-filling policy.