Abstract
Legitimately monitoring suspicious wireless communications is important for national security. In this letter, we investigate average monitoring rate maximization problem for a legitimate monitoring system, which proactively monitors a suspicious wireless link via jamming over multiple-input-multiple-output Rayleigh fading channels. We propose to approximate mutual information rates by Gaussian distributions. Furthermore, we propose low-complexity eigenvalue-based methods to calculate the means and variances of mutual information rates. Simulation results demonstrate that our proposed Gaussian approximation methods perform almost the same with the method to employ true probability density functions of mutual information rates.