  We consider a downlink multiuser multiple-input multiple output (MIMO) system
employing regularized zero-forcing (RZF) precoding. We derive the asymptotic
signal-to-leakage-plus-noise ratio (SLNR) as both the number of antennas and
the number of users go to infinity at a fixed ratio. Focusing on the symmetric
uncorrelated channels, we show that the SLNR is asymptotically equal to
signal-to-interference-plus-noise ratio (SINR) which allows us to optimize the
user loading for spectral efficiency. The results show that the optimal user
loading varies depending on the channel signal-to-noise ratio (SNR) but is
equal to one in both the low or high SNR regimes.
