System Capacity of 72 GHz mmWave Transmission in Hybrid Networks

Applying 6-100 GHz spectrum to mobile communications is a promising topic in 5G. In this paper, a hybrid network is presented where LTE system at low frequency works for seamless coverage and a mmWave system at 72 GHz works in hotspots for capacity enhancement. The scheme for the hybrid network includes: 1) frame structure and OFDM-based numerology for 72 GHz; 2) time-space beam switching method for beamforming; 3) zero-forcing MIMO precoding for interference cancellation; 4) a channel model based on measurements in [1] for simulation. System-level simulations show that the hybrid network can achieve the system throughput over 1600 times higher than that in 2 GHz frequency band in case of two streams. MIMO precoding is not mandatory for capacity enhancements because the effect of intra-cell interference is not severe. Thus, 72 GHz is a promising spectrum band that can well meet 5G requirements from the aspects of capacity and maximum data rate.