Artificial Noise Aided User Scheduling for Optimal Secrecy Multiuser Diversity

Abstract

In this letter, we propose a user scheduling scheme, which enables non-scheduled users to generate artificial noise in order to enhance wireless security in a multiuser wiretap network, where there exist N users, a single desired receiver, and K eavesdroppers. Our proposed scheme can achieve the optimal multiuser diversity gain (i.e., log log N) by adopting appropriate threshold values for scheduling feedback, which is also able to significantly reduce signaling overhead. We mathematically prove the achievability based on the derivation of a secure user-scaling law. Simulation results demonstrate that the proposed scheme achieves a better average secrecy rate than the conventional scheme in a finite N case, even if both schemes obtain the same secure user-scaling law as N → ∞.