“…Rayleigh fading [1,2,14,15] to the case where correlation is present at one of the two sides [8,11,16,17] or at both sides [18] or even Ricean fading channels [6,19]- [21], exact, closedform capacity expressions are inherently hard to derive due to the complex distribution of the eigenvalues of HH † . In order to obtain more informative analytical insights into MIMO systems, a large number of works has focused on formulating upper and lower capacity bounds for both SU-MIMO (see [2,3,13,22]- [26]) and MU-MIMO systems [4,27] via Jensen's inequality 2 .…”