Visible Light Communication Data Research Articles

The Possibility of Using VLC Data Transfer in the Smart Home

Abstract: In connection with the development of the technological concepts Smart Home (SH), Smart Metering, Smart Grids, the Internet of Things (IoT), new ways of transmitting information using a suitable communication medium are looked for in the above-mentioned technological concepts with an emphasis on security and transmission speed, robustness and interworking of various wireless and wired technologies in SH. The work deals with testing information transmission using LED lights for VLC (Visible Light Communication) communication in Smart Home. The paper describes the possibilities of using a standardized communication medium KNX Twisted Pair technology for possible links with VLC for intercommunication between the individual technologies implemented in SH. Using the proposed broadcast system of VLC transmission, M-QAM modulation is tested here for various values of the carrier wave for the different distances in SH.

2.0-Gb/s Visible Light Link Based on Adaptive Bit Allocation OFDM of a Single Phosphorescent White LED

In this paper, we present a high-speed visible light communication (VLC) system based on a single commercially available phosphorescent white light-emitting diode (LED). In this system, a preequalization circuit is used to extend the modulation bandwidth, and a differential output receiver is utilized to reduce the system noise. With adaptive bit and power allocation and orthogonal frequency-division multiplexing (OFDM), we experimentally demonstrated a 2.0-Gb/s visible light link over 1.5-m free-space transmission, and the BER is under a preforward error correction limit of 3.8×10 -3 . To the best of our knowledge, this is the highest white-light VLC data rate using a single phosphorescent white LED.

LED path recovery in a moving sensor

Existing Visible Light Communication (VLC) methods can recover each LED's on-off status only after its projection location is identified on each image. Identifying the LED projection is challenging because: 1) Clutter and noise corrupt the measurements; 2) The LED status will be “off” in some frames; 3) The predicted projection location sequence depends on the estimated vehicle state trajectory, which is uncertain. This article presents a new method determining the q most probable data and LED position sequences simultaneously, using Bayesian multiple hypothesis tracking (MHT) techniques by maximizing posterior probabilities. This article focuses on the VLC data and LED position sequence extraction, that includes vehicle state estimation. The MHT based algorithm is demonstrated by the simulation results.

Design and experiment of post-equalization for OOK-NRZ visible light communication system

Considering that the white LED’s spectral response decreases exponentially with the increase of carrier frequency for the on-off-keying non-return-to-zero (OOK-NRZ) visible light communication (VLC) data links, a first-order RC high-pass filter is designed and fabricated as a post-equalizer (PE) to compensate the LED spectral response. Formulation and simulation are both available for illustrating the VLC performance with and without PE. Experiments are performed in detail for the fabricated OOK-NRZ VLC system integrated with PE. The data transmission results show that by using PE, the measured carrier bandwidth is enhanced from 0.8 (0.4–1.2) MHz to 1.7 (0–1.7) MHz, and the bit-error-rate (BER) is less than 10−9. It proves the feasibility of the proposed scheme in OOK-NRZ VLC data links.