Amplify and Forward Relay-aided Power Line Communication Systems with Multiple Eavesdroppers for Renewable Smart Grids

In this paper, we investigated the physical layer security of a relay-assisted power line communication system operating over a multiple-input multiple-output channel for renewable smart grids. The objective is to transmit confidential signals between a source and a distant destination while facing the presence of multiple colluding or non-colluding eavesdroppers. We consider a two-phase jamming scheme that utilizes a full-duplex amplify-and-forward relay. In order to maximize the secrecy rate, we optimize the jamming precoding and transmitting precoding matrix both at the source and the relay subject to transmit power constraints. An efficient block coordinate descent algorithm is utilized to address the optimization problem. The simulation results validate the convergence and performance of the proposed algorithm. Additionally, the numerical findings indicate that the proposed algorithm surpasses the traditional scheme without jamming in terms of achieving a higher secrecy rate. Consequently, the proposed algorithm provides the advantage of ensuring secure communications in a model with realistic channels and multiple colluding eavesdroppers.