CAREER: Taming the Terahertz for 6G Wireless Backhaul

Oklahoma State University, Stillwater OK

Investigators

Abstract

An essential element of next-generation 6G wireless communications will be wireless backhaul. Backhaul is the network link that moves massive data streams at high speed between two points, supporting large subnetworks of mobile and fixed-location users. Normally optical fibers carry backhaul data, but fiber deployment is not always viable; wireless backhaul provides the high-speed alternative and solution. 6G will be the first generation of widely deployed wireless communication that has data rates comparable to fiber optics, heralding important benefits to our nation and society. Rural and remote populations may especially benefit from wireless backhaul, since it supports broadband connectivity (helping to close the digital divide) where fiber deployment is cost prohibitive. Wireless backhaul would also enable temporary high-speed networks critical to operations in mobile military units, natural disaster recoveries, or seasonal endeavors, such as smart and connected farming. Even the fiber-dominated networks in urban centers may economically and logistically benefit from the high flexibility and relatively low installation cost of wireless backhaul segments. Further, 6G wireless backhaul will strategically leverage the long-underutilized terahertz spectrum between 0.1-10 THz. Realizing ubiquitous 6G networks will require much new research, but terahertz backhaul is an important first step. The proposed work will utilize a combination of unique experimental measurements, theoretical models, and new device designs to fill knowledge gaps in the understanding of terahertz backhaul performance under real-world conditions. The knowledge gained will establish the critical foundations upon which future 6G systems can be intelligently engineered and optimized. Moreover, this work will train a new generation of students, from high school to graduate levels, inspired to work in electrical engineering and capable of advancing the highly complex wireless communications and sensing technologies in the future. To date, experimental demonstrations of terahertz communication are still very rare, leaving numerous scientific gaps in the holistic understanding of the impact of the atmosphere, antenna pointing, weather, and turbulence, especially when employing the backhaul requirements of ultrawide bandwidth and long distance. This dearth of measurements further leads to an inability to properly validate comprehensive theoretical models used in system engineering. The project goals and scope involve three thrusts: 1. to measure real terahertz backhaul links and enable gap issues to be studied and properly understood; 2. to use experimental measurements as the validation standard upon which theoretical channel models can be corrected and made more comprehensive; 3. to develop multi-functional reflectarrays, which are devices that can actively correct – in situ – terahertz communication problems such as antenna pointing, turbulence, and beam distortion. The measurement method will rely on a unique NSF-funded suite of terahertz systems that are purposely built to enable sensitive, long-distance, ultrawide bandwidth operations, both indoors and outdoors. The theoretical modeling will be extended to account for backhaul-unique properties, such as ultrawide bandwidth, and to unify the various physical mechanisms into a single comprehensive tool by which backhaul system behavior can be predicted in any practical circumstance. Reflectarrays will be designed by advancing artificial electromagnetic material concepts for backhaul specific purposes. These efforts will enhance terahertz wireless communication knowledge, improve theoretical models, and invent multi-functional devices that improve the power efficiency, speed, versatility, and reliability of future 6G wireless systems. This project is jointly funded by the Communications, Circuits and Sensing Systems (CCSS) Program and the Established Program to Stimulate Competitive Research (EPSCoR). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.