  Hybrid analog and digital beamforming has emerged as a key enabling
technology for millimeter wave (mmWave) massive multiple-input multiple-output
(MIMO) communication systems since it can balance the trade-off between system
performance and hardware efficiency. Owing to the strong ability of central
control, cooperative networks show great potential to enhance the spectral
efficiency of mmWave communications. In this paper, we consider cooperative
mmWave MIMO systems and propose user association and hybrid beamforming design
algorithms for three typical hybrid beamforming architectures. The central
processing unit (CPU) of the cooperative networks first matches the service
pairs of base stations (BSs) and users. Then, an iterative hybrid beamforming
design algorithm is proposed to maximize the weighted achievable sum-rate
performance of the mmWave MIMO system with fully connected hybrid beamforming
architecture. Moreover, a heuristic analog beamforming design algorithm is
introduced for the fixed subarray hybrid beamforming architecture. In an effort
to further exploit multiple-antenna diversities, we also consider the dynamic
subarray architecture and propose a novel antenna design algorithm for the
analog beamforming design. Simulation results illustrate that the proposed
hybrid beamforming algorithms achieve a significant performance improvement
than other existing approaches and the dynamic subarray architecture has great
advantages of improving the energy efficiency (EE) performance.
