On the Secure Degrees of Freedom of Wireless X Networks
Security is an important issue if the transmitted information is confidential. Researchers have studied the information theoretic secrecy for different channel models. In, Wyner first proposed the wiretap channel model to characterize single user secure communication problem, i.e., a sender transmits a confidential message to its receiver while keeping a wire-tapper totally ignorant of the message. The secrecy level is measured by the equivocation rate, i.e., the entropy rate of the confidential message conditioned on the received signal at the wire-tapper.