Current Status of 6G Development According to 3GPP Release 20

In Release 20, 3GPP began studying approaches for developing 6G mobile communication technologies. This paper aims to systematize the solutions considered in 3GPP by August 2026, compare them with 5G mechanisms, and assess their maturity. The analysis covers design principles, the physical layer, radio access network architecture, integrated sensing methods, and energy-saving mechanisms. Particular attention is paid to the native integration of artificial intelligence: the paper traces the transition from individual machine learning functions in 5G-Advanced to a common framework for data collection, model inference, monitoring, and lifecycle management. For each area, the paper distinguishes solutions supported during the study phase, solutions under discussion, and proposals from individual companies. Available quantitative evaluations are presented, and open problems are identified in cross-vendor model interoperability, reproducibility, robustness, radio resource sharing, and energy consumption.