A Survey on Energy-Efficient Next-Generation Wireless Terahertz Communications

Abstract

The emergence of sixth-generation (6G) wireless networks demands unprecedented improvements in data rates, connectivity, and energy-efficiency (EE), making the terahertz (THz) band a key enabler due to its vast, underutilized spectrum and high spatial resolution. This survey stands apart from previous studies by providing the first comprehensive, energy-centric analysis of THz communications, along with key 6G technologies and applications to offer a holistic roadmap toward sustainable, high-performance THz communication systems. The survey begins with a detailed examination of THz band characteristics, including propagation models and environmental influences. Key technical hurdles are identified alongside a survey of the current landscape, which includes standardization efforts, real-world testbeds, and industry adoption trends in THz technology. The critical importance of EE in 6G systems is emphasized through a comprehensive assessment of key energy challenges and optimization initiatives, followed by an in-depth analysis of energy-efficient THz communication techniques, such as hybrid beamforming and energy harvesting (EH), with a particular focus on material and device innovations, system-level modeling, and network-level adaptive communication protocols. Furthermore, the integration of THz communication with emerging technologies is analyzed from an energy-centric perspective, supported by comparative tables. This survey also maps diverse application scenarios, from nano-networks and healthcare to Industry 4.0 and military, and concludes with a discussion of open research challenges and future directions for THz system development.