Channel Characteristics of Visible Light Communications Within Dynamic Indoor Environment

Abstract

Visible light communications (VLC) is a new emerging technology, which provides both data transmission and illumination by utilizing the visible range (370 780 nm) of the electromagnetic spectrum. In order to maximize the available data rate and enhance the users mobility within an indoor environment, it is essential to characterize the communication channel. In this paper we present both analytical and experimental results for a VLC system affected by movement of people for different indoor conditions (i.e. furnished office room, empty hall and corridor). VLC systems utilize multiple light-emitting diodes mounted in the ceiling and the configuration is based on the non-directed line of sight. We consider random movement of people within the room, focusing on the impacts of shadowing and blocking on mobility and link system performance by investigating changes in the channel characteristics using the cumulative distribution function of the received power distribution and the delay profile. We demonstrate the behaviour of communication channels for different scenarios from corridor, the most robust against people movement induced fading, to the office rooms and halls, the most vulnerable to the received power fluctuation.

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

“…Apart from this preliminary work, Farahneh et al [45] modelled the shadowing effects encountered in visible light scenarios by a bimodal Gaussian distribution and derived the probability of error for low, moderate and severe shadowing conditions. However, there is still a paucity of studies on the general shadowing model of indoor VLC systems, although recently some valuable studies characterized the impact of the recievers' mobility and of human behaviour on the VLC system's performance [46], [47]. Chvojka et al [46] investigated the changes in channel characteristics caused by blocking and showed that the corridor model is the most robust, while the office/hall model is the most vulnurable one against people's movements.…”

“…However, there is still a paucity of studies on the general shadowing model of indoor VLC systems, although recently some valuable studies characterized the impact of the recievers' mobility and of human behaviour on the VLC system's performance [46], [47]. Chvojka et al [46] investigated the changes in channel characteristics caused by blocking and showed that the corridor model is the most robust, while the office/hall model is the most vulnurable one against people's movements. Furthermore, Bas et al [47] highlighted the impact of the moving human body on a VLC link, which is of more significance in VLC systems.…”

Performance Analysis of Classification Methods for Indoor Localization in VLC Networks

“…According to (Chvojka, 2015), both parameters are assigned a value of 60 degrees, to ensure validity of the implemented channel model, since the calculation of received optical power takes into account only the direct component of the signal.…”

“…The rest of the selected values employed to characterize VLC transmitters and receivers are commonly used values in literature, similar to those used in (Chvojka, 2015) (Tronghop, 2012 …”

Visible Light Communications towards 5G

“…The measured probability density function of the normalized received optical power considering people's movement as well as the analysis of the RMS delay spread for different indoor scenarios and people densities in rooms was carried out in [44]. Based on the measurement campaign the normalized received power showed a Rayleigh distribution with the scale parameter varying from 0.98 to 1.79 for an empty to a crowded room.…”