The Effect of Power Allocation on Visible Light Communication Using Commercial Phosphor-Converted Led Lamp for Indirect Illumination

2021 IEEE International Conference on Communications Workshops (ICC Workshops)

Pinho

et al. 2021

Self Cite

This paper studies the effect that the color temperature of an LED lamp has on the ability of a Visible Light Communication (VLC) system to detect different events, which could be the presence, position, and/or color of an object in the sensing area. The proposed VLC-based monitoring system takes advantage of the Channel State Information (CSI) that the VLC receiver estimates regularly for OFDM equalization, and makes use of K-means++ clustering to estimate the number of events that can be identified in the collected CSI data. The color temperature of the LED lighting is varied by changing the fraction of the total radiant flux emitted by Cool-White and Red-Orange LEDs, respectively, enabling to obtain a complete palette of white light that ranges from warm reddish (2600 K) to cool blueish (6200 K). The experimental evaluation is carried out with the aid of a software-defined VLC demonstrator, and shows that the sensing performance when using the reflected VLC signal to estimate the position of the object does not vary notably with the color temperature of the LED lamp. In contrast, the use of white light with high Color Rendering Index provides better results when the objective is to identify the color signature that different objects create when placed in the sensing area.

Section: Signal Processing In Baseband Ofdm Transmitter (Tx)mentioning

confidence: 94%

Effect of the Color Temperature of LED lighting on the sensing ability of Visible Light Communications

2021 IEEE International Conference on Communications Workshops (ICC Workshops)

Pinho

et al. 2021

Self Cite

“…A simple way to address this issue consists in using indirect illumination, such that the LED light is reflected back from the room ceiling to distribute light more uniformly [11], [12]. In this context, a reflective surface design framework was proposed in [13] to reach the desired illumination uniformity.…”

Section: Introductionmentioning

confidence: 99%

Visible Light Communication System in Presence of Indirect Lighting and Illumination Constraints

ICC 2020 - 2020 IEEE International Conference on Communications (ICC)

Hämäläinen

2020

Self Cite

Visible Light Communication (VLC) systems are designed to provide illumination and data services simultaneously. To achieve this goal, LED lamps are usually deployed on the room ceilings, in order to maximize the chances of having Line-of-Sight (LoS) connectivity between the VLC transmitter and the random locations that the VLC receiver can take. In an early stage of adoption, where the cost of LED lighting fixtures enabled with VLC technology will not be suitable for ultra-dense deployments, it is expected that only one VLC transmitter is placed per room. In this situation, the use of direct illumination may have serious problems to satisfy the illumination constraints and provide a homogeneous data rate coverage. Moreover, the use of a single powerful LED lamp per room may create discomfort glare effect to users and over-exposure problems in areas of the room at which the light beam is directed. In order to address these problems, this paper studies the data rate that VLC technology can achieve with indirect illumination. That is, when the LED lamp is pointing upwards, and the VLC user receives the optical signal that is reflected back from the ceiling. Obtained simulation results show that indirect illumination provides a more homogeneous data rate coverage when compared to direct case, while simultaneously verifying the illumination constraints in most of the places that the VLC receiver may take in the room.

“…Since VLC systems take advantage of existing lighting infrastructure, the most common deployments rely on direct illumination, where the LED lamps are placed on the ceiling to illuminate the faced-up PDs located in beneath [15]. An indirect illumination setting has also been proposed in references such as [16], [17], where the LED lamp is pointing upwards, and the PD receives the light that is reflected back from the (white) ceiling.…”

Section: Introductionmentioning

confidence: 99%

Random forest learning method to identify different objects using channel estimations from VLC link

2020 IEEE 31st Annual International Symposium on Personal, Indoor and Mobile Radio Communications

Vangapattu

et al. 2020

Self Cite

This paper demonstrates the feasibility of using supervised learning algorithms to identify the presence of different objects, taking advantage of the effect that they create on the VLC channel gains. For this purpose, a software-defined VLC link is implemented using a Phosphor-converted LED, whose light intensity is modulated by an Optical OFDM frame that includes synchronization words and pilot sequences for channel estimation. Actual estimated channel gains are collected in the receiver, which are used to train and assess the performance of the Random Forest classifier. The accuracy of the monitoring system is evaluated using three different objects, showing an accuracy in the order of 90% in detecting the objects, even when they take different positions when obstructing the VLC link.