Interference alignment based secure transmission scheme in multi-user interference networks

Abstract

Faced with the requirement of information security in internet of things, a scenario of multi-user interference networks with multiple eavesdroppers was considered, and an interference alignment (IA) scheme based physical layer secure transmission was proposed.Traditional IA security algorithm may result in secret signal cancellation.To overcome this threat, a modified alternating minimization (AM) method was proposed.The multi-user interference was eliminated by alternatively optimizing transceiver matrices, and artificial noise (AN) aided max-eigenmode beamforming was employed for secure transmission.To obtain a more accurate analysis of IA feasibility, the IA equation was divided into independent subsets and their combinations.By analyzing each case, a much tighter necessary condition for IA feasibility was established.Finally, the power allocation ratio between the secret signal and the AN signal was optimized to maximize the secrecy outage probability (SOP) constrained secrecy rate.Numerical results confirm that both the quality and security of the secret signal have been enhanced.Therefore, the proposed scheme is more suitable and reliable for security applications in interference networks.

Keywords

• interference alignment;physical layer security;artificial noise;secrecy outage probability;secrecy rate