International audienceThis paper presents two new simulation algorithms of the optical wireless channel based on the Markov Chain Monte Carlo method. They allow to generate correlated three-dimensional light paths, keeping into account the nature of the simulation environment, taking advantage of its complexity such as transmitter and receiver position and orientation, the geometry, and the nature of the surfaces (diffuse, specular, etc.). Like Markov Chain Monte Carlo methods, these new algorithms are adaptive. They automatically do more calculation where light paths transport more power. Hence, they optimize their convergence speed, reducing the required number of paths to achieve a given accuracy threshold for the channel impulse response calculation. This paper shows that, compared to previous classical Monte Carlo solutions, these new algorithms reduce the computation time, up to a factor 225 for a fixed quality according to our experiments
International audienceThis paper presents a new optimized simulation algorithm of the optical wireless channel. It has a faster convergence for SISO (Single Input Single Output) systems, while it significantly reduces computation time for MISO (Multiple Inputs Single Output) systems, which are the main ones in WBANs (Wireless Body Area Networks). Our algorithm is based on Monte Carlo methods, and uses 3D launched rays. Its main difference with previous solutions relies on reversing the process of propagation of optical waves, to solve efficiently and in real environments the global illumination equation modeling the propagation of light. Experimental results and comparisons with the literature are given in terms of precision and computation time
International audienceShadowing impact for indoor mobile visible light communications (VLC), is linked to the person wearing the optical receiver, depending on the body features and varying according the data rate. Here, we investigate VLC performance considering two body models with different reflectivity values. In addition, we consider a mobile receiver with random orientations to account body movements. Results show that for low data rates, a 2D body model with perpendicular receiver orientation allows suitable performance estimation. For high data rates, 2D body model can be used but link efficiency is deteriorated depending on receiver orientation variations whatever body reflectivity values are
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