Terahertz radio waves for sensing and localization in future 6G communication systems

Future wireless services and applications will in addition to communication functionality frequently necessitate an environment and localization information from the wireless communication system, thus, coexistence of the communication, sensing and localization is envisioned in 6G system. For example, the concept of the Digital Twin, the promising technology for a new immersive digital life with variety of application areas (Industry 4.0, aviation, healthcare, etc.), requires that the physical environment is sensed, processed and delivered to the digital world in real time. These and similar applications are expected to be supported by the sixth generation of communication systems (6G) that will in addition to communication provide environment sensing functionality. The requirements for 6G communication systems (Tbps data rates, tenths of a millisecond delay, millimeter-precision sensing and ranging, increase spectral efficiency and function encompassing the sensing, localization and control) can be attained by several innovative technologies, of which the terahertz (THz) frequency band (0.1-10 THz) is receiving significant attention as a key enabler. The THz frequency band has several benefits important for localization and sensing (signals do not penetrate objects, higher bandwidths, smaller antennas), but there are also some drawbacks for operating at THz frequencies (high propagation loss, higher losses due to reflection, diffraction and scattering, attenuation due to atmospheric effects). The design and implementation of joint communication, environment sensing and precise localization approach in 6G communication systems requires accurate characterization and modeling of the THz radio channel. In this context, the main goal of the project is to investigate, identify and develop novel THz channel models suitable for the design and evaluation of joint communication, environment sensing, and precise localization in an indoor environment exploiting the 6G communications in THz frequency bands. The project goal will be achieved by addressing the following objectives, namely, (i) an in-depth study of the main propagation mechanisms in the THz frequency band and identification of methodology requirements for joint communication, sensing and localization in the indoor environment, (ii) modeling a set of an identified propagation mechanisms and channel parameters and augmenting channel models with selected mechanisms, (iii) design of a novel method for environment sensing and localization exploiting the THz frequency band by applying the identified channel properties and (iv) prove and evaluate the performance of the proposed approaches in identified indoor scenarios by designing the architecture for selected scenarios and generating test data sets by upgraded in-house developed THz radio propagation tool. We believe that the properties of the THz radio channel can be exploited for joint communications, environment sensing and precise localization in future 6G systems. Thus, the work will initially focus on identifying propagation phenomena and channel parameters that are critical for joint communication, sensing and localization in indoor environments. Emphasise will then be placed on channel models suitable for joint communication, sensing and localization with a focus on recognizing the adequate existing channel models, identifying their deficiencies and limitations, and developing new or improved models for indoor environments based on new THz channel measurements in indoor environments. Research will continue by investigating the different localization approaches using radio signals and identifying their suitability for the THz band as well as developing novel approaches. Finally, the evaluation of the proposed approaches in relevant 6G indoor scenarios will be performed by testing data set generated with an updated in-house developed radio propagation tool and THz channel measurements.