A Simulation Framework and Performance Evaluation of a Hybrid LiFi–RF Backscatter System for Battery-Free IoT

The rapid growth of the Internet of Things (IoT) has increased the demand for sustainable, battery-free communication solutions. This paper presents a Simulink-based model of a modified Passive LiFi system that combines visible light communication (VLC) for the downlink with RF backscatter for ultra-low-power uplink transmission. Custom behavioral models are developed for key components, including a solar cell, boost converter, and optocoupler-based driver, to overcome limitations in standard libraries. The model captures the complete communication chain, incorporating OOK-based LiFi transmission, tag-side signal conditioning, and CSS demodulation. System performance is evaluated in terms of BER, SNR, and CDF, showing strong agreement with experimental results. The BER and SNR evaluations are based on comparison between transmitted and reconstructed signals, considering inherent system non-idealises. These results represent an upper-bound performance under idealized conditions. The proposed framework provides a flexible and cost-effective platform for the design and evaluation of hybrid LiFi–RF backscatter systems.