Performance Analysis of Novel Direct Access Schemes for LEO Satellites Based IoT Network

This paper analyzes the performance of low earth orbit (LEO) satellites based internet-of-things (IoT) network, where each IoT node makes use of multiple satellites to communicate with the ground station (GS). In this work, we consider fixed and variable gain amplify-and-forward (AF) relaying protocol at each satellite, where the received signal from each IoT node is amplified before transmitting to the GS for data processing. The performance of this novel LEO satellites based direct access architecture is analyzed by deriving closed-form expressions of outage probability (OP) for two combining schemes at the GS: (i) selection combining (ii) maximal ratio combining. Both these schemes are also compared with single satellite (SS) scenario. Further, to gain more insights for diversity order and coding gain, asymptotic OP analysis at high SNR for both schemes is also performed. Finally, simulation results are presented to validate the analytical results derived and also to develop several interesting insights into the system performance.