# AI-Enhanced Hybrid QAM–PPM Visible Light Communication for Body Area Networks

## TL;DR

This paper proposes an AI-enhanced visible light communication system for body area networks using a hybrid QAM–PPM modulation framework to improve communication reliability and efficiency.

## Contribution

The novel contribution is integrating AI-driven equalization with a hybrid QAM–PPM modulation framework for robust and high-rate VLC in body area networks.

## Key findings

- The hybrid QAM–PPM modulation framework improves spectral efficiency and robustness in VLC systems.
- AI-driven equalization using CNN–transformer layers enhances symbol reconstruction under LED nonlinearity and channel variability.
- Adaptive bit loading and pilot-assisted equalization strengthen link robustness and spectral efficiency in diverse conditions.

## Abstract

This paper investigates an artificial intelligence (AI)-enhanced visible light communication (VLC) system for body area networks (BANs) based on a hybrid modulation framework that jointly employs quadrature amplitude modulation (QAM) and pulse-position modulation (PPM). The dual-modulation strategy leverages the high spectral efficiency of QAM together with the robustness of PPM to light-emitting diode (LED) nonlinearity and timing distortions, enabling simultaneous high-rate and reliable communication, two essential requirements in BAN applications. To address the nonlinear response of light-emitting diodes and the variability in indoor optical channels, the system integrates classical predistortion techniques with a deep learning equalizer combining convolutional neural network (CNN)–transformer layers. This hybrid model captures both local and long-range distortion patterns, improving symbol reconstruction for both modulation branches. The study further examines pilot-assisted equalization and adaptive bit loading, showing that these strategies strengthen link robustness under diverse channel conditions while enhancing spectral efficiency. The proposed architecture demonstrates that combining dual modulation with AI-driven equalization and adaptive transmission strategies leads to a more resilient and efficient VLC system, well-suited for the dynamic constraints of wearable and body-centric communication environments.