Channel Analysis and Performance Enhancement for VLC under Smoke Conditions

Visible light communication (VLC) is widely used in communication systems due to its high transmission rate and strong resistance to electromagnetic interference characteristics. However, smoke in the environment can affect the visible light channel, which reduces transmission distance and even results in communication failure. Therefore, we propose a VLC system to analyze the communication performance under smoke conditions and improve communication distance. First, we establish a reasonable channel model that accords with the actual conditions of smoke based on the Mie scattering theory and the Monte Carlo method. We simulate visible light transmission in smoke conditions and enhance the theoretical analysis upper limit of visible light communication performance according to the channel model. Furthermore, we propose an enhanced modulation method based on pulse position modulation (E-PPM), effectively reducing the bit error rate of communication data and improving the transmission distance by increasing the duration of high levels. Finally, the established channel model can accurately reflect the transmission performance of white LED in smoke conditions, and the proposed modulation method can effectively reduce the system's bit error rate and increase the transmission distance by 0-0.5m.

I. Introduction

Visible light communication (VLC) is a communication method that can transmit information while achieving illumination [1]. Currently, research on VLC is conducted chiefly in indoor environments without interference [2]. However, in many cases, VLC is subject to external environmental interference. In the past, many researchers conducted a series of atmospheric laser communications in complex environments such as smoke and fog. Still, little research on VLC is based on white LED in smoke. Prashant Dwivedy et al. [3] proposed a non-orthogonal multiple access (NOMA) collaboration technique using two different modulation schemes to reduce the bit error rate of visible light communication systems. Dixit et al. [4] proposed a multiple-input multiple-output method based on L-PPM modulation for visible light communication to reduce the bit error rate of the system and achieve a higher data rate network. Wang et al. [5] proposed using Volterra nonlinear equalizers for VLC systems based on high-speed carrier-free amplitude and phase modulation. Although the above methods can effectively increase the communication distance, they do not consider the smoke environment.