The Design of an Indoor Non-Line-of-Sight Wireless Optical Communication System

Wireless optical communication (WOC) technology represents a cutting-edge form of wireless communication. Nevertheless, conventional WOC technologies typically require line-of-sight (LOS) conditions, necessitating precise alignment between the transmitter and receiver, and these systems can be easily disrupted by physical obstructions. To overcome these limitations, this paper leverages the diffuse reflection properties of light off indoor surfaces to develop a novel WOC system. The proposed system consists of a transmitter, an LED array, a receiver, and the wireless channel. It employs Pulse Width Modulation (PWM) for data transmission and incorporates a carrier frequency of 100 kHz to minimize interference from ambient light sources. Experimental results demonstrate that, within a room of dimensions 5m × 5m × 3m, non-line-of-sight (NLOS) communication can achieve a bit error rate (BER) below 3×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup> when the distance between the receiver and transmitter is less than 2 meters. This finding highlights the potential of the proposed system to provide robust and reliable communication in indoor environments without the stringent requirement for direct line-of-sight.