Joint Communication and Indoor Positioning Based on Visible Light in the Presence of Dimming

TL;DR

This paper introduces a joint visible light communication and indoor positioning system that achieves high-precision localization and reliable data transmission by leveraging advanced signal processing and dimming control in complex indoor environments.

Contribution

It presents a novel integrated VLC system combining spatial modulation, a pilot-aided LS estimator, and the radical axis theorem for enhanced accuracy and robustness in joint communication and positioning.

Findings

Achieves sub-centimeter localization accuracy at high SNRs.

Maintains BER below 10^{-6} with low-order PAM schemes.

Performance improves near the center of the LED layout.

Abstract

This paper proposes a joint communication and indoor positioning (JCP) system based on visible light communication (VLC) designed for high-precision indoor environments. The framework supports 2D and 3D positioning using received signal strength (RSS) from pilot transmissions, enhanced by the radical axis theorem to improve accuracy under measurement uncertainties. Communication is achieved using spatial modulation (SM) with M-ary pulse amplitude modulation (PAM), where data is conveyed through the modulation symbol and the active light-emitting diode (LED) index, improving spectral efficiency while maintaining low complexity. A pilot-aided least squares (LS) estimator is employed for joint channel and dimming coefficient estimation, enabling robust symbol detection in multipath environments characterized by both line-of-sight (LOS) and diffuse non-line-of-sight (NLOS) components, modeled using Rician fading. The proposed system incorporates a dimming control mechanism to meet lighting requirements while maintaining reliable communication and positioning performance. Simulation results demonstrate sub-centimeter localization accuracy at high signal-to-noise ratios (SNRs) and bit error rates (BERs) below 10^{-6} for low-order PAM schemes. Additionally, comparative analysis across user locations reveals that positioning and communication performance improve significantly near the geometric center of the LED layout. These findings validate the effectiveness of the proposed system for future 6G indoor networks requiring integrated localization and communication under practical channel conditions.