Experimental Characterization of Close-Emitter Interference in an Optical Camera Communication System

Area of Science:

• Optoelectronics and Optical Communications
• Wireless Sensor Networks
• Internet of Things (IoT)

Background:

• Optical Camera Communication (OCC) is a promising technology for IoT and smart cities, leveraging embedded cameras and LED lighting.
• Existing research has addressed environmental factors affecting Visible Light Communication (VLC), but spatial interference between close OCC emitters requires further characterization.
• Understanding wavelength-dependent interference is crucial for optimizing OCC system performance.

Purpose of the Study:

• To experimentally characterize spatial intersymbol interference in Optical Camera Communication (OCC) systems as a function of transmitted wavelength.
• To propose and validate a novel metric, the Normalized Power Signal to Interference Ratio (NPSIR), for quantifying interference independently of specific system hardware.
• To develop and validate equations for predicting interference and communication link performance in real-world scenarios.

Main Methods:

• Conducted darkroom experiments using RGB multi-LED transmitters and a general-purpose camera to measure interference.
• Calculated Normalized Power Signal to Interference Ratio (NPSIR) values based on experimental data.
• Developed and validated equations for 2D pixel representation of distances and interference.
• Simulated a wireless sensor network scenario to calculate Bit Error Rate (BER) using derived parameters.

Main Results:

• The study successfully characterized wavelength-dependent spatial interference between close OCC emitters.
• Proposed NPSIR metric effectively quantifies interference based on distance and wavelength.
• Validated equations for predicting interference and scaling results to real-world office environments.
• Demonstrated the practical applicability of NPSIR for interference assessment in diverse OCC implementations.

Conclusions:

• NPSIR provides a universal method for determining interference in OCC systems, irrespective of specific devices used.
• The validated equations enable accurate prediction of interference and communication performance in wireless sensor networks.
• This research contributes to the reliable deployment of OCC technology in future IoT and smart city applications.