Enhancing Physical Layer Security in Internet of Things via Feedback: Revisit

Physical layer security (PLS) in the down-link transmission of Internet of Things (IoT) systems is modeled as the compound wiretap channel (C-WTC). Recently, it has been shown that channel feedback helps to enhance the secrecy capacity of the C-WTC, where the channel feedback is used to generate secret keys protecting the transmitted message from being eavesdropped by the eavesdropper. In this paper, we show that for the Gaussian compound wiretap channel (GC-WTC), a hybrid feedback scheme that combines the existing secret-key type feedback and a variation of the classical Schalkwijk-Kailath (SK) type feedback scheme, performs better than the already existing one in the literature. The study of this paper offers a new option for the enhancement of the PLS in IoT systems.