Performance Analysis of Integrated Satellite-Aerial IoT Networks for Remote Environmental Monitoring With Link Switching Scheme

In remote environmental monitoring Internet of Things (IoT) deployments, UAV-ground direct links frequently experience hard blockage, whereas satellite relay transmission requires higher power. Therefore, an effective link-switching mechanism is needed to balance communication reliability and UAV energy consumption. To address these challenges, an integrated satellite-aerial IoT system is considered for remote environmental monitoring. Sensor data are aggregated by an unmanned aerial vehicle (UAV) and transmitted through either a short-range direct link with Rician fading or a two-hop satellite relay path with Shadowed-Rician fading. Specifically, a new link switching scheme is proposed. The ground terminal uses the low-power direct link by default and activates the satellite relay only upon hard blockage or when the signal-to-noise ratio falls below a switching threshold. Based on the proposed scheme, outage probability, ergodic capacity, and average bit error rate are derived in closed‑form for the considered system. Numerical results verify that the shadowing parameter, blockage probability, and the proposed switching strategy significantly affect the overall system performance. The proposed strategy yields 87%–99% outage reduction across three monitoring scenarios, and the relay activation frequency is primarily governed by the blockage probability rather than shadowing conditions.