Towards intelligent reflecting surface empowered 6G terahertz communications: A survey

TLDR

Terahertz communications are viewed as a key enabler for 6G, offering ultra‑high bandwidth, yet they face challenges such as severe attenuation, complex channel modeling, material constraints, and deployment hurdles. The study proposes using intelligent reflecting surfaces to mitigate THz blockage, thereby improving spectrum efficiency and coverage. IRS‑empowered THz systems support scenarios like mobile, secure, UAV, MEC, and localization, relying on hardware design, channel estimation, capacity optimization, beam control, resource allocation, and robustness techniques. Combining IRS with THz technology can accelerate the development of 6G wireless networks.

Abstract

Terahertz (THz) communications have been widely envisioned as a promising enabler to provide adequate bandwidth and achieve ultra-high data rates for sixth generation (6G) wireless networks. In order to mitigate blockage vulnerability caused by serious propagation attenuation and poor diffraction of THz waves, an intelligent reflecting surface (IRS), which manipulates the propagation of incident electromagnetic waves in a programmable manner by adjusting the phase shifts of passive reflecting elements, is proposed to create smart radio environments, improve spectrum efficiency and enhance coverage capability. Firstly, some prospective application scenarios driven by the IRS empowered THz communications are introduced, including wireless mobile communications, secure communications, unmanned aerial vehicle (UAV) scenario, mobile edge computing (MEC) scenario and THz localization scenario. Then, we discuss the enabling technologies employed by the IRS empowered THz system, involving hardware design, channel estimation, capacity optimization, beam control, resource allocation and robustness design. Moreover, the arising challenges and open problems encountered in the future IRS empowered THz communications are also highlighted. Concretely, these emerging problems possibly originate from channel modeling, new material exploration, experimental IRS testbeds and intensive deployment. Ultimately, the combination of THz communications and IRS is capable of accelerating the development of 6G wireless networks.