To tackle the problem that radio signal in the terahertz band had different features compared to that in the conventional spectrum, which restricted its application to indoor communication scenarios, a modified propagation model of terahertz radio signal was proposed. Based on the model, the propagation and coverage performances of wide-band single-carrier terahertz radio signal were analyzed. In particular, the wide-band terahertz channel transfer function was constructed, taking the absorption loss introduced by the thickness of the obstacles into account. Using the ray tracing technique, the impacts of the obstacles' thickness and the bandwidth on the propagation and coverage performances were examined, showing that the coverage performance can be improved by leveraging the reflections from the non-line-of-sight obstacles. Moreover, the trade-off between the coverage radius and the capacity of terahertz communications is revealed, and it is further found that the theoretical spectral efficiency decreases as the carrier frequency of terahertz radio signal increases. © 2022, Editorial Board of Journal on Communications. All right reserved.
