Although Terahertz communication systems can provide high data rates, it needs high directional beamforming at transmitters and receivers to achieve such rates over a long distance. Therefore, an efficient beam training method is vital to accelerate the link establishment. In this study, we propose a low-complexity beam training scheme of terahertz communication system which uses a low-cost small-scale hybrid architecture to assist a large-scale array for data transmission. The proposed scheme includes two key stages: (1) coarse AoAs/AoDs estimation for beam subset optimization in auxiliary array stage, and (2) accurate AoAs/AoDs estimation by exploiting channel sparsity in data transmission array stage. The analysis shows that the complexity of the scheme is linear with the number of main paths, and thus greatly reduces the complexity of beam training. Simulation results have verified the better performance in spectral efficiency of the proposed scheme than that of the related work.

翻译：虽然Terahertz通信系统可以提供高数据率,但需要高方向波束对发射机和接收器进行高方向波束调整,才能在长距离内达到这种波段,因此,高效的波束培训方法对于加快建立链接至关重要。在本研究中,我们提议对地铁通信系统采用低复杂波束培训计划,该系统使用低成本的小型混合结构,协助数据传输的大型阵列。拟议计划包括两个关键阶段:(1) 在辅助阵列阶段对波音小集优化进行粗略AoAs/AoDs估计,以及(2) 通过利用数据传输阵列阶段的频道宽度进行准确的AoAs/AoDs估计。分析表明,方案的复杂性与主路数是线性的,从而大大降低了波段培训的复杂程度。模拟结果证实,拟议方案在光谱效率方面的业绩优于相关工作。