Low complexity but near optimal hybrid beamforming design in tera‐hertz communication systems: principles and opportunities

Next generation communication systems go to tetra-hertz (THz) frequency bands. In this article, low-complexity but near-optimal hybrid beamforming design is investigated in THz by considering its unique channel characteristics and discuss potential research opportunities. Specifically, the THz channel characteristics are explored from its propagation feature, angular orthogonality and bandwidth. The authors clarify the differences between the THz multiple-input-multiple-output (MIMO) and its low-frequency counterparts (e.g. mmWave MIMO). Low complexity but near-optimal hybrid beamforming design in THz are summarised in the following typical scenarios, namely the single-user and multi-user downlink system, integrated data and energy transfer system and the intelligent reflecting surface aided system. Simulation results demonstrate the near-optimality of our hybrid beamforming design. Some critical open issues in the THz communication system are discussed for future research interest.