Abstract
Millimeter wave (mmWave) system attracts much research attention because it provides very wide bandwidth for 5G communications. However, mmWave channel has limited scattering and suffers severe path loss for radio transmissions. The hybrid RF and baseband multiple-input multiple-output (MIMO) precoding (beamforming) is a potential technique to solve these problems. This study proposes a hybrid beam tracking algorithm to reduce the computational complexity in mobile environments. A partially updated algorithm based on the optimal precoder/combiner correlation between successive channels was proposed to determine the updating condition in the continuous drifting channel model, in which AoA, AoD, channel gain, and phase change continuously. Simulation results show that the complexity of the proposed algorithm was reduced by 21.4%∼45.3% in the precoder and 27.7%∼49.8% in the combiner in a 16 × 16 MIMO system with mobile station (MS) speed of 15 km/hr.