Jammer assisted SEE maximization in decode-and-forward relay network

In this paper, the energy efficiency of secure communication in a wireless decode-and-forward (DF) relay network is studied using friendly jammer. Our objective is to maximize the secure energy efficiency (SEE), measured as the numbers of bits transmitted secretly per unit of energy consumed under power constraint on each node and target secrecy rate constraint. SEE maximization requires the optimal selection of helper nodes as relays and jammer, and then the power allocation among them. The SEE maximization is achieved by joint power allocation between the source, relays and a jammer in global channel state information (CSI) scenario. In this paper, the optimal jammer and relay set is selected iteratively by a simple jammer and relay selection scheme to avoid mix integer formulation of the optimization problem. The resulting problem is solved by a joint application of fractional programming, exact penalty, alternate search, and difference of convex functions programming.