Enhancing wireless secrecy via cooperation: Signal design and optimization

Physical layer security, or information-theoretic security, has attracted considerable attention recently, due to its potential to enhance the transmission secrecy of wireless communications. Various secrecy signaling and coding schemes have been designed at the physical layer of wireless systems to guarantee confidentiality against information leakage to unauthorized receivers, among which the strategy based on the idea of node cooperation is promising. This article provides an overview of the recent research on enhancing wireless transmission secrecy via cooperation. We take a signal processing perspective and focus on the secrecy signal design and optimization techniques to increase secrecy performance. We also propose some future research directions on this topic.