Optimal User Loading in Massive MIMO Systems With Regularized Zero Forcing Precoding


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.