Terahertz (THz) band has been envisioned as a promising enabler that achieves high-speed information transmission and provides adequate spectrum resources for future sixth generation (6G) wireless systems. However, due to the extremely high frequency and the strong directionality of THz waves, the wireless communication links in such a frequency range (from 0.1 THz to 10 THz) suffer from serious path loss, multi-path fading, communication interruption and poor coverage. To this end, the intelligent reflecting surface (IRS) is proposed to improve the coverage performance for the indoor THz communication scenarios. Interestingly, the IRS is able to smartly reconfigure the propagation of electromagnetic waves by adjusting the discrete phase shifts of the IRS elements. Although the exhaustive phase shift search scheme can significantly enhance the coverage capability of THz communication, it involves the unacceptable computation complexity. Subsequently, a low complexity phase shift search scheme, called suboptimal search scheme, is proposed by just selecting the partially better combinations of discrete phase shifts. Simulation results show that the proposed suboptimal search scheme is able to achieves the near-optimal coverage performance and greatly decreases the computational burden compared with the exhaustive search method. Moreover, the ray-tracing technique is leveraged to validate effectiveness of the IRS in practical application scenarios.

太赫兹（THz）频段已被设想为实现高速信息传输并为未来的第六代（6G）无线系统提供足够频谱资源的有前途的促成因素。但是，由于太赫兹波的极高频率和强烈的方向性，在这种频率范围（0.1太赫兹至10太赫兹）中的无线通信链路遭受严重的路径损耗，多路径衰落，通信中断和覆盖范围差的困扰。为此，提出了一种智能反射面（IRS）来提高室内太赫兹通信场景的覆盖性能。有趣的是，IRS能够通过调整IRS元件的离散相移来巧妙地重新配置电磁波的传播。尽管穷举相移搜索方案可以显着增强THz通信的覆盖能力，但它涉及到无法接受的计算复杂性。随后，通过仅选择离散相移的部分更好的组合，提出了一种称为次优搜索方案的低复杂度相移搜索方案。仿真结果表明，与穷举搜索方法相比，提出的次优搜索方案能够实现接近最优的覆盖性能，并大大降低了计算量。此外，在实际应用场景中，利用射线跟踪技术来验证IRS的有效性。通过选择部分更好的离散相移组合，提出了一种称为次优搜索方案。仿真结果表明，与穷举搜索方法相比，提出的次优搜索方案能够实现接近最优的覆盖性能，并大大降低了计算量。此外，在实际应用场景中，利用射线跟踪技术来验证IRS的有效性。通过仅选择部分更好的离散相移组合，提出了一种称为次优搜索方案。仿真结果表明，与穷举搜索方法相比，提出的次优搜索方案能够实现接近最优的覆盖性能，并大大降低了计算量。此外，在实际应用场景中，利用射线跟踪技术来验证IRS的有效性。