3D Channel Models: Principles, Characteristics, and System Implications

This article presents a comprehensive review of the principles and characteristics of 3D channel models. We propose a framework for a 3D channel extension of the widely used 2D 3GPP/ ITU generic channel model. We describe the main components and challenges of the newly proposed 3D channel model and the motivations that lie behind them. 3D channel models specify multipath elevation angles as well as azimuth (or horizontal plane) angles. This enables the evaluation of 3D MIMO techniques such as FD MIMO and per user 3D beamforming. We also provide a state-of-the-art review on the evolution of channel models. The article ends with a discussion on the impact of 3D channel modeling on system-level performance.