Channel Modeling for Space-Aerial-Terrestrial Integrated Networks (SATIN)

With the development of communication technologies, space-aerial-terrestrial (SAT) heterogeneous networks have emerged in the context of 6th-Generation (6G) communications. Incorporating various communication systems and devices, such as satellites and unmanned aerial vehicles (UAVs), they operate via complex and diverse communication links, which require accurate channel models. This article first reviews the developments and requirements of these communication links by focusing on the current state of research and challenges in channel modeling between such heterogeneous networks. In an effort to unify these methods, a general channel modeling approach is proposed by considering a SAT integrated network (SATIN). By introducing fictitious reference points at an altitude level of approximately 8km above the ground, SAT channels can be divided into upper- and lower-level channels. The advantage of this approach is that each channel can be modeled using different methods, while the complete channel impulse response can be obtained by convolving known data for the two channels thus allowing flexible utilization of existing channel models. Through a case study it has been shown that, by taking the measured path loss as a reference, the path loss generated by the proposed approach is more accurate than that obtained from the standard channel models.