Analysis of the Outage Probability of Ground-Based Relaying for Satellite Systems

TL;DR

This paper provides a theoretical analysis of ground-based relaying in satellite systems, deriving closed-form expressions for outage probability under various fading models and CSI conditions, demonstrating minimal performance loss with limited power.

Contribution

It introduces exact closed-form formulas for outage probability in multi-antenna satellite relaying with shadowed-Rician and Fluctuating Two-Ray fading models, considering perfect and imperfect CSI.

Findings

Closed-form outage probability expressions derived for different fading scenarios.

Minimal performance loss when only phase estimation is used without full CSI.

System performance can be accurately predicted using ideal state formulas under non-ideal conditions.

Abstract

This paper investigates the theoretical basis for using ground relaying in multi-antenna satellites exposed to blocking situations. Inactive and unobstructed User Equipments (UEs) located on ground are the relaying nodes of UEs that are not in the field of view of the satellite. Exact closed-form relationships of the Signal-to-Noise Ratio (SNR) and the outage probability are obtained for the case where each user is connected to two transmitting antennas at the satellite. The channel between the satellite and ground is modeled as a shadowed-Rician (SR), whereas a Fluctuating Two-Ray (FTR) fading model is used for the mmWaves ground link between relay and UE, as well as cases with perfect and imperfect Channel State Information (CSI). The simulation results showed that if perfect CSI is not available in the pre-coding and only the signal phase is estimated, the performance loss is minimal and the system can reach its ideal performance by spending limited power. In any case, the closed-form for the ideal state are a good proxy to predict the performance under non-ideal conditions.