Secrecy metrics for physical layer security over fading channels

Physical layer security over fading channels has drawn a considerable amount of attention in the literature. How to measure the secrecy performance is a fundamental but important issue for the study of wireless physical layer security. This chapter gives a comprehensive overview of the classical secrecy metrics as well as several new secrecy metrics for physical layer security over fading channels, which enables one to appropriately design secure communication systems with different views on how secrecy is measured.