Outdoor Visible Light Communication Channel Modeling under Smoke Conditions and Analogy with Fog Conditions

Abstract

Visible Light Communication (VLC) has gained popularity in research and business in the last decade. This technology aims to combine lighting and communication into a single device. For now, this technology has been thoroughly studied for an indoor environment, but it is sufficiently mature nowadays to consider its outdoor-environment potentials. The key outdoor challenges are the weather variabilities and smoke particles in cities due to pollution or fires. The aim of this is the study and quantification of the weather and smoke particles’ impact on a short-range optical communication thanks to a simulator. This article’s novelty is the inclusion of the effects of smoke in a short-range outdoor VLC system channel model. This smoke model, which comes from the fire engineering field, states that smoke attenuation is independent of the wavelength, starting from high visibility to 5 m. The visibility represents the distance up to which an object can be distinguished against the background. The effects of fog and smoke are studied in the case of two outdoor VLC scenarios. Smoke and fog models have analogous equations to express the optical attenuation they induce, using the visibility concept. Taking into account the actual light-emitting diode (LED) lamp radiation pattern, the simulator computes the power at the receiver side and the channel attenuation coefficients for a given fog or/and smoke outdoor setting. The main result drawn in this paper is that the channel attenuation levels due to fog and smoke are both in the same order of magnitude, starting from the visibility of about 1 km. The attenuation induced by fog is higher under this threshold of 1 km.

Design and performance evaluation of vehicular visible light communication system under different weather conditions and system parameters

“…where 𝑉 is the visibility range, 𝜆 is the operating wavelength, and 𝑇 is the coefficient that describes the fog thickness. This coefficient can be calculated according to the Kruse model in terms of the visibility factor as [25] 𝑇 = { 1.6, 𝑉 > 50 1.3, 6 < 𝑉 < 50 0.585𝑉 1 3 ⁄ , 𝑉 < 6 .…”

A Survey of Vehicular VLC Methodologies

“…On the other hand, other analytical studies showed that under conditions of dry ice, which has proven to have a more significant effect than fog on vehicle connection (with dense fog representing the most challenging environment), it was possible to obtain reliable communication according to the experimental measurements, reaching about 20 m. This was accomplished using image sensors at the receiver side, while the connection using PDs was about 15 m, which was the maximum distance achieved using other modulation schemes [ 103 , 104 , 105 ]. The effects of weather and smoke particles on visible short-range communications were examined and evaluated in [ 106 ]. Other factors with a negatively impact are fires, pollution, and smoke particles, which are also considered significant issues.…”

“…Moreover, the idea of visibility as a starting point for smoke and fog models uses the same kinds of equations to explain the optical attenuation, they induce to adjust the smoke and fog effect ratio. The channel attenuation coefficients were calculated using an energy simulator on the receiving side, considering the actual radiation pattern used in the LED, which reached about one kilometer [ 106 , 107 ].…”

Wireless Sensor Networks Using Sub-Pixel Optical Camera Communications: Advances in Experimental Channel Evaluation

“…Outdoor scenarios, where the weather and other atmospheric phenomena play an important role in the propagation of optical signals [ 32 ], have been experimentally investigated in the OWC field and recently in VLC, as summarized in [ 33 ]. In [ 34 ], an outdoor link of approximately 400 m was experimentally validated, which exploited defocusing the camera, allowing the surface of the LED to be extended and the transfer rate to be increased to 450 bps (bits per second).…”