Experimental characterisation and modelling of the reflection of infrared signals on indoor surfaces

Abstract

The performance of non-line-of-sight indoor wireless infrared communication systems depends on the re ection characteristics of the surfaces that surround the communication space. This paper presents a set of measured re ection patterns of the most common indoor surfaces and the approximation of those experimental patterns using two re ection models: the model of Lambert and the model of Phong. The results show that the re ection pattern of many surfaces present a strong specular component. Those patterns are well approximated by the model of Phong, but not by the model of Lambert. It is also shown that the use of the model of Lambert to approximate the re ection pattern of specular surfaces can lead to errors of several dBs in the evaluation of the propagation losses.

A Genetic Algorithm Method for Optical Wireless Channel Control

“…Assuming that the majority of surfaces in our environment exhibit a fully diffuse, as supposed to specular [21]- [23], reflection characteristic that can be described by Lambert's reflection model [24], we can apply the following simplification. Regardless of whether the transmitter is composed of multiple optical sources or a 2-D VCSEL/RCLED array, the resultant diffusion spots on the ceiling will exhibit a Lambertian radiation intensity pattern, and therefore from this point onwards, each of the I diffusion spots on the ceiling will themselves be considered independent sources S i .…”

Simulation of impulse response for indoor visible light communications using 3D CAD models

“…In this article, Phong's model has been used [11,13]. In contrast to Lambert's model, this model is able to approximate reflections consisting of both specular and diffusive components, which are described by…”

Evaluation of visible light communication channel delay profiles for automotive applications

“…It is known that the reflection pattern of most surfaces can correctly be approximated using the Lambert or the Phong models. If there are strong specular components in the reflection pattern of the surfaces, the Phong model approximates those patterns well unlike that of the Lambert model [15,16]. However, the surface conditions in urban areas are irregular and reflect optical signals without favoring any particular direction.…”