PROPAGATION CHARACTERISTICS AND SYSTEM PERFORMANCE OF TERAHERTZ–OPTICAL HYBRID COMMUNICATION CHANNELS

Abstract

This paper investigates the propagation characteristics and system performance of terahertz–optical hybrid communication channels. To meet the increasing demand for high capacity and high reliability in future high-speed wireless communication systems, a hybrid communication model consisting of a terahertz link and an optical wireless link is established. First, the dominant propagation impairments are analyzed, including free-space path loss, molecular absorption, and pointing errors in the terahertz link, as well as atmospheric attenuation, turbulence effects, and pointing errors in the optical wireless link. Then, a hybrid channel model is developed based on an instantaneous signal-to-noise-ratio-based link selection mechanism, and outage probability, bit error rate, and channel capacity are selected as the main performance metrics. Numerical results show that the terahertz and optical wireless links exhibit clear complementarity in terms of propagation impairments. Compared with single-link transmission, the terahertz–optical hybrid communication system can effectively reduce the outage probability and maintain more stable system capacity under different transmission distances and propagation conditions. The results of this work may provide useful guidance for the design of future 6G high-speed wireless backhaul and reliable communication systems in complex environments.