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
Communications inside an aircraft cockpit are currently based on wired or radiofrequency connections. For instance, wireless ones have been introduced to support the tablets. However, the use of radiofrequency technologies remains limited. For example, a wireless connectivity for the headset would be an advantage for the pilots in terms of comfort and flexibility but there are some issues especially concerning radiofrequency interferences but also audio data security. Optical wireless communications based on visible light or infrared offer interesting possibilities to overcome these issues. Indeed, as optical beams are confined in the environment, this technology brings robustness against the risks of attacks, thus increasing security. In addition, radiofrequency immunity ensures the absence of disturbances, allowing more resources for communications. For the first time in the literature and using simulation, this paper investigates the optical wireless channel for pilot headset connectivity inside aircraft cockpit, and determines its performance in terms of maximal data rates that can be achieved for a given link reliability.
. In this paper, we propose an approach to model radio wave propagation in these frequency bands in arched shape cross section straight tunnels using tessellation in multi-facets. The model is based on a Ray-Tracing tool using the image method. The work reported in this paper shows the propagation loss variations according to the shape of tunnels. A parametric study on the facets size to model the cross section is conducted. The influence of tunnel dimensions and signal frequency is examined. Finally, some measurement results in an arched cross section straight tunnel are presented and analyzed in terms of slow fadings and fast fadings.
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