Research on fading characteristics of ultrahigh frequency signals in Karst landform around radio quiet zone of FAST

摘要

Ultrahigh frequency wireless signals are mainly influenced by the geomorphological environment during the transmission process, resulting in fading channels, especially in mountainous regions. The experiment was conducted in the Karst landform of Guizhou Province, China, in order to explore fading distribution characteristics for mainly analyzing electro magnetic compatibility (EMC) specialties between Five-hundred-meter Aperture Spherical Radio Telescope (FAST) and wireless radiation equipment around radio quiet zone of this telescope. Based on the channel variation data of six frequencies, which are mainly used by the electrical and electronic equipment of public facilities around FAST, the fading distribution was analyzed by using the Kolmogorov-Smirnov statistic method. And finally we determined the optimal distribution model with the fading range, fading depth, and fading rate. The results show that (1) the polarization type and signal frequency have a definite influence on the fading distribution types in the Karst landform; (2) Rice distribution is the optimal and stable distribution model in the Karst landform, and the log-normal distribution model is proposed to characterize the Rice K-factor distribution; and (3) the line-of-sight (LoS) components of the normalized envelopes are 0.6837, 0.8939, 0.5963, 0.6332, 0.5516, and 0.4806. And the multipath scattered components of those are 0.2134, 0.0630, 0.2436, 0.2224, 0.2678, and 0.2880. The research results provide a potential support for the deployment and optimization of wireless communication networks in Karst landform, especially around radio quiet zone of FAST.