Abstract5.1 Higher-Frequency Operation and Spectrum Flexibility5.2 Ultra-Lean Design5.3 Forward Compatibility5.4 Transmission Scheme, Bandwidth Parts, and Frame Structure5.5 Duplex Schemes5.6 Low-Latency Support5.7 Scheduling and Data Transmission5.8 Control Channels5.9 Beam-Centric Design and Multi-Antenna Transmission5.10 Initial Access5.11 Interworking and LTE Coexistence