Fundamental limits in correlated fading MIMO broadcast channels: Benefits of transmit correlation diversity

We investigate fundamental limits of the capacity of correlated fading MIMO broadcast channels (BCs) in several regimes of system parameters, with a particular interest in the large-scale array (or massive MIMO) regime. It is advocated in this paper that transmit correlation can be of use to increase both multiplexing gain and power gain in multiuser MIMO systems. In particular, it is shown to improve the system multiplexing gain up to by a factor of the number of degrees of transmit correlation diversity that captures how favorable structure users have in their transmit correlations.