Cooperative jamming and power allocation in three-phase two-way relaying system with untrusty relay node

This paper investigates the physical layer security issue of the three-phase two-way relaying system with an untrusty relay node. New cooperative jamming schemes are proposed for the three-phase bi-directional secrecy communications. The transmit power of each source node is divided into two parts corresponding to the user and jamming signals, respectively. The minimum jamming signal power at each source node is analyzed. An iterative power allocation algorithm is proposed for the three-phase protocol. Numerical results demonstrate the superiority of the proposed cooperative jamming scheme with power allocation.