Modeling of single-scatter NLOS/LOS ultraviolet communication channels based on threshold sphere and performance analysis in mobile scenarios

Based on the scattering characteristics of ultraviolet light, the existing studies on ultraviolet communication (UVC) channels mainly focus on non-line-of-sight (NLOS) links, but lack research on line-of-sight (LOS) links. In this paper, a single-scatter sphere-threshold-based NLOS/LOS UVC channel model is proposed by introducing an imaginary threshold ball. The analytical expressions for the path loss (PL) of the LOS link and the whole link are derived. The simulation results demonstrate that the proposed model aligns closely with the Monte Carlo model, and in the presence of LOS links, its root mean square error (RMSE) is only 0.1138 dB. Further, the expressions for the PL and the channel impulse response (CIR) when the receiver is moving are derived, and the impact of parameters such as motion speed and motion direction is systematically analyzed. The results show that the PL and the CIR are more sensitive to the coplanar-noncoplanar transition (CNT) when the transmitter and receiver are close to a coplanar state at the initial time. In addition, the distance between the transmitter and receiver is the dominant factor affecting channel performance in all scenarios.