Ka-Band LEO Satellite Internet of Things Channel Characterization: Survey and Measurement

In this work, the LEO Land Mobile Satellite (LMS) channel at Ka-band is studied. This work firstly reviews existing Ka-band LMS channel models and measurements, which are mostly related to model the dynamic characteristics for LEO satellite communications, specifically in a restrictive small satellite platform. Moreover, as pervasive satellite Internet of Things (IoT) networks involve on-ground users with low-gain and non-directional antennas, multipath effects cause a frequency selective fading of the received signal. Although extensive propagation experiments are carried out for Ka-band LMS systems, experimental characterizations and studies on multipath effects are lacking. Therefore, this work aims to address this limitation by considering the critical issue of the multipath effects on the Ka-band LEO propagation channel. Hence, we present the results of recent propagation experiments and investigate the multipath effects on Ka-band LEO SATCOM links. The results show comparably large values for the delay spread especially in mountainous scenarios. It is further revealed that results on the multipath propagation that are derived from terrestrial measurements may not be transformed to the LEO satellite channel without the need for adaption.