Research on the sixth generation (6G) wireless systems towards 2030 is now the center of attention as 5G is becoming a commercial reality. To realize a high-fidelity holographic society, connectivity for all things and time-sensitive applications, even larger system bandwidths are required in 6G along with new physical layer techniques and higher layer capabilities. New frequency band from 100 GHz to 1 THz is thus considered as a candidate for 6G. Especially, the D-band (110-170 GHz) is very attractive for its low atmospheric absorption loss and wide spectrum, which is promising for advanced applications such as wireless backhaul, WiFi access, velocity sensors, passive cameras, radar, navigation, on-body communication, etc. As the first step to design any new generation system, it is essential to investigate the radio propagation channels because they are distinct at different frequency bands and fundamentally constrain the system design. The propagation research aims to measure radio channels (channel sounding), extract channel parameters e.g. delays, angles-of-arrival/departure, polarization matrix and Doppler shifts of path components from recorded data (parameter estimation) and build mathematical representations of radio channels (channel modeling). Since the early developments of wireless communications in the 1950s and 1960s, extensive channel sounding efforts have been made to investigate the radio channels. However, only a handful of recent works have been performed to investigate the lower THz propagation channels, and little is known about their characteristics. The main challenges include difficulties in developing double-directional channel sounders for dynamic channel characterization, extracting channel parameters from the measurement data efficiently and accurately, and establishing comprehensive and realistic 6G-compatible channel models.
Therefore, the main research goal of this project is to explore the new lower THz frequency band by creating novel and basic theory, technology and knowledge in channel sounding, parameter estimation and modeling for lower THz channels, hence gain the very first understanding and provide guidelines for developing wireless systems operating at the lower THz band. The project will achieve its ambition by the following three specific objectives:
1) developing a novel real-time lower THz channel sounder that can capture dynamic channels. Meanwhile, other parameter domains including delay, double directions and dual polarizations are also well considered (WP1)
2) developing a novel, generic and low-complexity high-resolution-parameter-estimation (HRPE) algorithm that is applicable for the lower THz channels (WP2)
3) establishing comprehensive and realistic lower THz channel models compatible for 6G-oriented applications, i.e. not only for communications but also for positioning and sensing purposes (WP3).
The proposed ideas have become realistically achievable, valuable and a must due to the advancements and demands in developing a new generation wireless system. The successful project is vital for realistic system design and performance analysis of communication, positioning and sensing at the lower THz band and will open up for many interesting future projects in those areas. The project output and results also contribute to Europe’s Digital Decade, i.e. Europe’s digital transformation by 2030, by facilitating an efficient, low-cost, credible, better, and timely development of 6G and beyond wireless systems.
