Abstract:

A two-hop relay-eavesdropper channel model with one transmitter, one relay, one receiver and one eavesdropper is considered, where the nodes harvest energy and the save-then-transmit protocol is employed. That is, the nodes harvest energy first, which is then used to transmit the data. The relay is operated as an amplify-and-forward relay, and the destination sends an intended jamming noise to protect information, which is referred as cooperative jamming. First, the condition that ensures the promotion of secrecy capacity is derived. Second, an optimization algorithm to maximize secrecy rate Rs is given, which is based on the optimization of the energy saving time ratio ρ and the jamming power allocation scaling factor α. Simulation results show that the algorithm has a high convergence speed, and can effectively improve secrecy rate.