Abstract

     Physical layer security (PLS) in Internet-of-Things (IoT) has attracted great attention in recent years. As an important and intrinsic property in an IoT system, node mobility is not fully investigated when designing a PLS scheme. Existing PLS works with mobility are designed with typical random mobile models, which cannot represent a real scenario. Considering this challenge, we propose a friendly jamming handover scheme to protect the downlink transmission from a controller to an actuator, with the help of multiple cooperative jammers to fight against a mobile conscious eavesdropper. In particular, we first introduce a conscious eavesdropping model (CEM) to characterize a real mobile wiretapping scenario. Second, we present a handover scheme to enhance security in a mobile scenario and then define handover efficiency to discuss the handover performance. Finally, numerical results are provided to verify the effectiveness of the proposed handover scheme, which demonstrates that our scheme can efficiently fight against a conscious mobile eavesdropper.

Introduction

     Internet of Things (IoT) is expected as a promising technique to achieve ubiquitous connectivity and intelligent information processing for the intelligent future life [1, 2]. Since the IoT is penetrating our daily life, the security and privacy are of the utmost importance [3–۵]. Physical layer security (PLS) techniques have been attracted growing interests for the scenarios with resource-constrained IoT sensors and actuators [6–۸]. A PLS scheme taking advantage of the unique properties of wireless channels can guarantee the information-theoretic communication security, regardless of the computing capability of eavesdroppers [9]. Various PLS schemes have been investigated to enhance secrecy in IoT networks, including multi-antenna beamforming and precoding [10, 11], artificial noise (AN) [12], intermittent cooperative jamming [13], and sociability-enabled PLS [8, 14, 15].

Conclusion

     This work investigated secure downlink transmmission in an IoT system with a mobile eavesdropper, and proposed a handover scheme to enhance PLS with the help of multiple cooperative jammers. In order to reflect the real situation, the conscious eavesdropping model was proposed to compare with the typical RWP model. Moreover, we introduced a metric called handover efficiency to reflect the handover performance. The numerical results verified that the handover scheme could efficiently improve the secrecy performance and effectively confront the conscious eavesdropper. The proposed scheme is feasible to provide security enhancement in many real mobile eavesdropping scenarios.