Simulation of impulse response for indoor wireless optical channels using 3D CAD models

Abstract

In this paper, a tool for simulating the impulse response for indoor wireless optical channels using 3D computer-aided design (CAD) models is presented. The tool uses a simulation algorithm that relies on ray tracing techniques and the Monte Carlo method and improves on all previous methods from a computational standpoint. The 3D scene, or the simulation environment, can be defined using any computer-aided design (CAD) software in which the user specifies, in addition to the setting geometry, the reflection characteristics of the surface materials as well as the structures of the emitters and receivers involved in the simulation. Also, in an effort to improve the computational efficiency, two optimizations are presented. The first consists of dividing the setting into cubic regions of equal size. These sub-regions allow the program to consider only those object faces and/or surfaces that are in the ray propagation path. This first optimization provides a calculation improvement of approximately 50%. The second involves the parallelization of the simulation algorithm. The parallelization method proposed involves the equal and static distribution of the rays for computation by different processors. This optimization results in a calculation speed-up that is essentially proportional to the number of processors used.