Jamming-Assisted Multi-User Multi-Eavesdropper Broadcast Network: PHY Layer Security Analysis

In this paper, the physical layer security of a multi-user jamming-assisted broadcast network in the presence of multiple eavesdroppers is investigated. Specifically, a base station (BS) is broadcasting data to multiple end-users via direct links in the presence of multiple passive wiretappers, while both the legitimate users and the eavesdroppers use a maximal-ratio combining scheme to achieve high spatial diversity gain. Furthermore, the BS is broadcasting a jamming signal that cannot be canceled by the eavesdroppers to increase their decoding failure rates. All links are subject to Nakagami- $m$ fading models. Relying on the upper incomplete moment-generating function of the combined Signal-to-interference-plus-noise ratio (SINR) at each wiretapper's MRC output, tight approximate and asymptotic expressions for the secrecy outage probability (SOP) are derived considering two different scenarios, i.e., (i) absence and (ii) presence of the broadcasted artificial noise. The impact of the jamming signal level, severity fading parameter, and the number of MRC branches are examined, while the most influential parameter on the system's security is retrieved. Numerical results and simulations reveal the accuracy of the obtained analytical expressions and gain more useful insights into the system's secrecy. © 2013 IEEE.