A Wavelength-Dependent Visible Light Communication Channel Model for Underground Environments and Its Performance Using a Color-Shift Keying Modulation Scheme

Abstract

Reliable wireless communications are crucial for ensuring workers’ safety in underground tunnels and mines. Visible light communications (VLC) have been proposed as auxiliary systems for short-range wireless communications in underground environments due to their seamless availability, immunity to electromagnetic interference, and illumination capabilities. Although multiple VLC channel models have been proposed for underground mines (UM) so far, none of these models have considered the wavelength dependence of the underground mining VLC channel (UM-VLC). In this paper, we propose a single-input, single-output (SISO), wavelength-dependent UM-VLC channel model considering the wavelength dependence of the light source, reflections, light scattering, and the attenuation due to dust and the photodetector. Since wavelength dependence allows us to model VLC systems more accurately with color-based modulation, such as color-shift keying (CSK), we also propose a wavelength-dependent CSK-based UM-VLC channel model. We define a simulation scenario in an underground mine roadway and calculate the received power, channel impulse response (CIR), signal-to-noise ratio (SNR), signal-to-interference ratio (SIR), root mean square (RMS) delay, and bit error rate (BER). For comparison, we also calculate these parameters for a monochromatic state-of-the-art UM-VLC channel and use it as a reference channel. We find that the inclusion of wavelength-dependency in CSK-based UM-VLC systems plays a significant role in their performance, introducing color distortion that the color calibration algorithm defined in the IEEE 802.15.7 VLC standard finds harder to revert than the linear color distortion induced by monochromatic CSK channels.

Research on channel modeling technology of visible light communication system based on the ray tracing method

“…The basic architecture of the VLC system mainly consists of three parts: LED-based transmitting frontend, Photo-Diode (PD)-based receiving front-end, and VLC channel (free space). The transmit module of the VLC system preprocesses and encodes the original binary data bit stream, then drives the LED lamps, performs intensity modulation on the white LED and electro-optical conversion of the modulated signal, and transmits the converted optical signal [5]. Since the indoor channel is relatively controllable compared to the outdoor channel, the transmission channel of the VLC system is more stable.…”

On the Performance of Intelligent Reconfigurable Surfaces for 6G Indoor Visible Light Communications Systems

“…Due to its significant dependence on having a line of sight, the direct light component is very affected by the effect of this phenomenon. In general, people, immobile objects, and moving elements produce shadowing, so we consider it coherent to introduce an error probability coefficient in the mathematical expression of the LoS component, as follows [24,27,28]:…”

“…where P is a weighting function that represents the probability that the LoS link will not be blocked [24,27,28]. This coefficient is a parameterized value between 0 and 1.…”