Modeling and Analysis on Dynamic Terahertz Channel Capacity in Hypersonic Plasma Sheaths

Communication blackout is always a serious threat to hypersonic and reentry vehicles in near space. Terahertz (THz) communication is a potential approach to mitigate the blackout. Previous studies have investigated the propagation characteristics of THz signals in plasma sheaths. Yet, the properties of THz channel capacities are still unclear so far. In the present study, a model of the THz channel capacity of plasma sheath is investigated. The parameters of plasma sheaths are obtained by solving the hydrodynamical model. The multiplicative interferences and additive noises in the plasma channel are modeled. The impacts of flight speed, wave frequency, antenna position, and the time-varying characteristics of plasma sheaths on the channel capacities are analyzed. In addition, an estimation model of the relationship between flight speed and channel capacity is obtained. The appropriate communication frequencies at different flight speeds are suggested at the end of the study. The present work may theoretically guide the design for onboard THz communication system serving hypersonic and reentry vehicles.