Ergodic Secrecy Rates of Secure Wireless Communications

Two unified analytical frameworks that facilitate the evaluation of the ergodic secrecy rates of Wyner wiretap channel in generalized fading environments without/with diversity receivers are developed. In contrast to prior work that is limited to only the Rayleigh fading environment, our new formulas expressed in terms of only the moment generating function (MGF) or the cumulative distribution function (CDF) of fading signal-to-noise ratio (SNR) random variables allow us to investigate the role of fading (i.e., Effects of the amount of fading and non-identical fade distributions) between the main and the eavesdropper links as well as the impact of diversity receivers on the ergodic secrecy rate performance metric. Numerical results show that non-zero ergodic secrecy rate can be achieved even if the link quality of the main channel is worse than the eavesdropper´s channel. We also show that the fundamental limit of secure communication rate can be greatly improved by understanding the role of dissimilar fading statistics and by exploiting/mitigating channel effects via diversity reception.