Jammer assisted sum rate and fairness improvement in secure OFDMA

We consider the problem of resource allocation among M untrusted mobile users with a source and a friendly jammer in a secure OFDMA system. The jammer can be utilized to improve either the sum secure rate or the fairness of the system. Since the optimization problem is combinatorial and belongs to the class of NP hard, we propose two independent suboptimal schemes to solve the resource allocation problem. Our simulation results demonstrate that the use of jammer helps trade between secure rate and fairness performance.