Outage Performance Of Secure Cooperative Communication Systems Over Correlated Fading Channels

Information security has traditionally been ensured by applying the cryptographic methods(e.g.,RSA and AES),which are implemented above the physical layer.However,the physical layer security,from the information theoretic perspective,is recognized as an approach to address privacy and security issues in wireless networks without upper-layer encryption.Hence,the physical layer security techniques have a promising prospect.And in recent years,the cooperative communication gained a lot attention thanks to its ability to reap diversity.The combination of cooperative communication and physical layer security can bring more guarantee of security for data transmission systems.From two aspects,we investigate the secrecy outage performance of the secure cooperative communication system over correlated Rayleigh fading channels.The main contributions are as follows:(1)The secure cooperative communication system uses opportunistic relay selection(ORS)scheme.Assuming that the transmitter knows the full channel state information(CSI)before transmission,there exist one eavesdropper and multiple cooperative relay nodes in system,and a relay node is chosen to act as jammer to send the jamming signals.Besides,in this cooperative communication system,the legitimate channel is correlated with the jamming channel to the destination,and the wiretap channel is correlated with the jamming channel to the eavesdropper.With this scenario,we first derive the expression of secrecy outage probability of the secure cooperative communication system.Also,we give high signal to ratio(SNR)approximations for the secrecy outage probability.Numerical results show that the channel correlation has significant impacts on the secrecy performance of the secure cooperative system.(2)We further study the effect of outdated channel state information on the secrecy outage performance of the secure cooperative communication system.Assuming that the channel state information of the relay node to the legitimate channel used in relay selection is outdated,we derive the expression of secrecy outage probability of the secure cooperative communication system in high SNR regime.Numerical results show that the outdated CSI has significant impact on secrecy performance of the secure cooperative communication system.Besides,the low channel self-correlation and high cross-correlation can reduce the secrecy performance of the secure cooperative communication system.