Intercept Probability Analysis of Joint User-Jammer Selection against Eavesdropping

In this paper, we investigate the physical-layer security for a wireless communications network comprised of multiple users and a common base station (BS) in the presence of an eavesdropper. We propose a joint user-jammer selection scheme for preventing the eavesdropper from intercepting the confidential user-BS transmission. Specifically, a user is first selected to transmit its message to the BS, while another user is chosen to act as a friendly jammer for emitting the artificial noise to interfere with the eavesdropper. We also consider the conventional multiuser scheduling as a benchmark. Closed-form intercept probability expressions are derived for the conventional multiuser scheduling and proposed joint user-jammer selection schemes over Rayleigh fading channels. Numerical results show that the proposed joint user-jammer selection significantly outperforms the conventional multiuser scheduling in terms of the intercept probability, especially with an increasing number of users.