SummaryThis paper deals with the use of jamming transmission for secure amplify‐and‐forward‐based relay networks with total power constraints. An approach that the source and the relay use some of their available power to transmit jamming signals in order to create interference at the eavesdropper is investigated. Assume that the relay and destination have an a priori knowledge of the jamming signals. A power allocation policy that defines how the available power is distributed between the message signal and that of the jamming signal is presented. The results show that the proposed approach can increase the secrecy level and that a positive secrecy rate can be achieved even when the eavesdropper may be near the source. Copyright © 2014 John Wiley & Sons, Ltd.

An artificial noise strategy is proposed for amplify-and-forward bi-directional relay network where the eavesdropper can wiretap the relay channels in both hops. Artificial noise is used to confuse the eavesdropper and improve its secrecy.Specifically, the source and the relay are allowed to split their available transmit power into 2 parts: a useful information portion and a jamming portion to transmit a jamming signal. The mathematical model is established for 2-way relay network with an eavesdropper. The secrecy rate achieved by using artificial jamming is derived from the above model. The optimal power allocation with individual power constraint is obtained via sequential quadratic programming to maximize the secrecy sum rate, and 2 special cases are investigated. Furthermore, the benchmark is provided for the purpose of performance comparison.Simulation results show that the proposed strategy can significantly improve the secrecy sum rate by using artificial noise to jam the eavesdropper. KEYWORDSartificial noise, amplify-and-forward, bidirectional relaying, physical layer security, power allocation Int J Commun Syst. 2018;31:e3464.wileyonlinelibrary.com/journal/dac