ADMM-Based Channel Estimation for mmWave Massive MIMO Systems

The millimeter wave (mmWave) combining with massive multiple-input multiple-output (MIMO) has become an attractive candidate for next generation cellular systems.However, estimating the channel sufficiently and accurately can be challenging due to both low coherence time and a large number of antennas. Based on the idea that mmWave channels will likely have a low rank structure relative to the number of antenna elements, this work formulates the channel estimation problem as a non-convex nuclear norm minimum optimization under noisy setting, and proposes a novel channel estimation algorithm based on alternating direction method of multipliers (ADMM) for mmWave massive MIMO system. Time division duplex (TDD) channel estimation is performed in this work. Our analysis and experimental results suggest that the proposed method outperforms the existing ones in terms of estimation error performance and pilot overhead, which doesn't require any knowledge about the statistical distribution or physical parameters of the propagation channel.