Optimal User Loading in Massive MIMO Systems
With Regularized Zero Forcing Precoding
Authors: Sungwoo Park, Jeonghun Park, A. Y. Panah, Robert W. Heath, Jr.
IEEE Wireless Communications Letters, vol. 6, no. 1, pp. 118-121, Feb. 2017
We consider a downlink massive multiple-input
multiple output system employing regularized zero-forcing
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 spatially
uncorrelated channels with homogeneous large scale fading gains,
we show that the SLNR is asymptotically equal to signal-tointerference-plus-noise
ratio, 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-tonoise
ratio (SNR). As the SNR increases, the optimal user loading
decreases at low SNR, but increases at high SNR.