LAUSR

This paper investigates the issue that whether the jamming in the second time slot should be utilized for secure two-way amplify-and-forward relay systems. Particularly, a more realistic and severe scenario is considered: no information related to the eavesdroppers is available and the number of eavesdroppers is not less than that of legitimate nodes. The impact of the jamming modes on the secure performance is carried out and reveals a novel insight that one-time-slot jamming outperforms two-time-slot jamming in high SNR region, i.e., one > two. A low-complexity and robust joint relay and partial jammer selection criterion is proposed, in which only jamming in the first time slot is employed and no wiretap information is required. Simulation results highlight the effectiveness of our design.