IQ-Impaired Wireless-Powered Modify-and-Forward Relaying for IoT Networks: An In-Depth Physical Layer Security Analysis

With the large-scale commercialization of 5G networks, the era of Internet-of-Things (IoT), which is oriented towards the internet-of-everything (IoE), is coming. Under the circumstance, reliable and secure communication are the great challenges for future wireless network because of the broadcasting
characteristics of electromagnetic wave. Physical layer security (PLS) is an effective way to ensure secure communication by exploiting random nature of fading channels. Motivated by this, we investigate PLS of the wireless-powered cooperative multirelaying for IoT networks in the presence of eavesdropper with the estimation errors of channel (EEC) and imbalance between in-phase and quadrature-phase (IIQ). Specifically, the relays can be charged by the source with the aid of energy harvesters, and a novel more secure modify-and-forward (MF) relay protocol is proposed. For further improving energy efficiency and reducing extra interference, the K-th superior relay selection scheme is proposed since some best ones are not available due to some scheduling or failure. Based on the system under study, we derive the analytical expressions for the outage probability (OP), intercept probability (IP) and secrecy outage probability (SOP) to evaluate the reliable and secure performance of this consideration system. Particularly, we then analyze the asymptotic behaviors of the OP, IP and SOP, respectively. Through computer simulation, we show that: i) With EEC, the error floors of the OP and SOP are of presence; ii) Multiple relays lead to better OP and SOP performance; and iii) IIQ improves the security and is detrimental to the system reliability.