Secure MISO Cognitive Radio System with Perfect and Imperfect CSI
In cognitive Radio (CR) systems, harmful interference from the secondary system degrades the data rate of the primary system. However, this interference may be beneficial to the primary system in terms of the secrecy rate, when unauthorized users eavesdrop on the primary link. This paper explores Multiple-Input Single-Output (MISO) CR systems where the secondary system secures the primary communication in return for permission to use the spectrum. In this paper, the optimal transmission strategy has to be found which provides the best tradeoff between the useful and harmful effects of interference on the secrecy rate of the primary system.