Secrecy Rate Optimization in Wireless Multi-Hop Full Duplex Networks

Physical layer security and full duplex have been two widely applied techniques in wireless communications community, where the physical layer security can prevent eavesdropping without the upper layer data encryption, while the full duplex can improve spectrum efficiency through simultaneous transmission and reception. In this paper, we jointly consider full duplex and security by investigating the cross-layer optimization problem to maximize the secrecy rate in the multi-hop wireless network. This combination aims to improve both spectrum efficiency and security of conventional wireless systems at the same time. We first construct a cross-layer secrecy rate model based on full duplex constraints, secrecy capacity constraints, and secrecy flow balance. Then, we formulate it into a mixed integer and non-linear programming problem and reformulate it with reformulation-linearization technique and convex hull relaxation into the linear form. Finally, we validate our proposed optimization method and algorithm through comparing it with half duplex and jamming to demonstrate that the proposed combination of security and full duplex achieve the significant improvement of spectrum efficiency and security.