Space-air-ground integrated networks (SAGINs) have attracted significant attention and become a promising architecture for meeting the ubiquitous connectivity requirements in 6G. The communication link from the high-altitude platform (HAP) to the offshore platform (OP) is an important component of SAGINs. The development of the hybrid FSO/RF system can effectively handle the problem that the FSO link is seriously affected by the weather. However, existing research lacks the analysis of the HAP to OP link, especially the analysis of the hybrid link switching frequency. In this work, we investigate the channel model between the HAP to OP. Then the influence of channel parameters on the switching probability of the hybrid system is analyzed, which providing guidance for the formulation of switching mechanisms for hybrid communication systems.

High-altitude platform (HAP), free space optical (FSO) channel, radio frequency (RF), switching probability, offshore platform (OP)