Secure wireless multicasting through Rayleigh fading channels — A secrecy tradeoff

In this paper, a wireless multicast scenario is considered in which the transmitter sends a common message to multiple client receivers in the presence of an eavesdropper. We are interested in protecting this common message against eavesdropping. Based on an information-theoretic formulation of the problem, in which the transmitter and the mutually independent multiple client receivers communicate over quasi-static Rayleigh fading channels and an eavesdropper observes their transmissions through another quasi-static Rayleigh fading channel, we define the secrecy-sum capacity in terms of secure outage probability. Moreover, we also present a formulation of ergodic perfect secrecy multicast capacity at which the eavesdropper is unable to decode any information.