A Hybrid Low-Complexity WMMSE Precoder with Adaptive Damping for Massive Multi-User Multiple-Input Multiple- Output Systems

Maximizing the weighted sum-rate (WSR) in downlink multi-user multiple-input multipleoutput (MU-MIMO) systems remains computationally challenging due to the prohibitive complexity of classical weighted minimum mean square error (WMMSE) algorithms. In this article, we propose a novel low-complexity WMMSE (LC-WMMSE) precoding method specifically designed for massive MU-MIMO downlink systems. Our algorithm introduces a hybrid switching approach that adaptively blends standard WMMSE updates with computationally simpler approximations derived via the Woodbury matrix identity, coupled with an adaptive damping mechanism to ensure robust and stable convergence. Simulation results demonstrate that the proposed LC-WMMSE method achieves WSR performance comparable to classical WMMSE but with significantly reduced computational complexity, making it particularly suitable for practical implementation for massive MUMIMO systems.