Enhanced optical visible light positioning via RSS-based evolutionary optimization under LOS and NLOS conditions

Positioning through visible light is a wireless method for positioning in optical communication This method has advantages such as low cost, safety and high accuracy compared to positioning based on RF. In this article, the Received Signal Strength algorithm (RSS) is used for locating. A hypothetical room with dimensions of 6 × 6 × 4 (m³) is considered and the receiver is located at a fixed height from the ground. The error due to the presence of shot noise, thermal noise and multipath and under the conditions of low power, in this method is about several tens of centimeters and is significant. Linear approximation itself is the cause of error. In order to reduce the error, genetic algorithm (GA) and particle swarm optimization (PSO) algorithm, which are an evolutionary method to minimize the error function, have been proposed instead of least squares estimation. The slope results show that the error is significantly reduced. It will also be shown that changing the distance between the LEDs leads to a difference in the positioning error. The higher the transmitted power, the lower the error. On the other hand, as the height increases, the error also increases, and the greater number of transmitters are used, the positioning error decreases. The simulation results show that the presence of reflection increases the positioning error. The value of the root mean square error (RMSE) for the Line-of-Sight (LOS) scenario is equal to 0.3493 m and for the Non-Line-of-Sight (NLOS) scenario is equal to 0.4461 m. Finally, a method for choosing the most powerful LEDs is suggested, this choice reduces the positioning error.