Analyzing Outage Performance in a UAV-Assisted Backscatter System Operating under Realistic Composite Fading Conditions

Lam Dong Huynh; Lam Thanh Tu; Tan N. Nguyen

Lam Dong Huynh Faculty of Electrical and Electronics Engineering, Ton Duc Thang University Ho Chi Minh City, Vietnam
Lam Thanh Tu Advanced Intelligent Technology Research Group, Faculty of Electrical and Electronics Engineering, Ton Duc Thang University Ho Chi Minh City, Vietnam
Tan N. Nguyen Advanced Intelligent Technology Research Group, Faculty of Electrical and Electronics Engineering, Ton Duc Thang University Ho Chi Minh City, Vietnam

Abstract

This paper analyzes the performance of a UAV-enabled backscatter communication system for low power IoT networks. The system consists of a power beacon that wirelessly energizes an energy constrained source node, which then transmits data to a UAV-mounted backscatter relay; the UAV reflects the signal to a destination. A realistic composite fading model is adopted: Rician fading for UAV-involved links (source-toUAV and UAV-to-destination) to account for dominant line of sight (LoS) components, and Rayleigh fading for the ground based power beacon to source link due to shadowing. The main contribution is the derivation of an exact closed form expression for the system’s outage probability using the Meijer G-function, enabling efficient performance evaluation without extensive simulations. The analysis incorporates a time switching protocol where the source alternates between energy harvesting and data transmission. Numerical results validate the analytical model and reveal critical insights: outage performance improves significantly with higher Rician K-factors (indicating stronger LoS), and an optimal time switching ratio exists that minimizes outage by balancing energy harvesting and data transmission durations. Additionally, hardware parameters such as backscatter coefficient and energy conversion efficiency strongly influence system reliability. The study also highlights the trade off between target data rate and outage probability, showing that higher beacon transmit power supports higher data rates at fixed reliability levels. These findings provide practical guidance for designing efficient UAV-assisted backscatter IoT systems.

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