Wireless access test-bed through visible light and dimming compatible OFDM

2015 ◽  
Author(s):  
Ali Mirvakili ◽  
Valencia J. Koomson ◽  
Michael Rahaim ◽  
Hany Elgala ◽  
Thomas D. C. Little
Keyword(s):  
Visible Light ◽  
Wireless Access ◽  
Test Bed ◽  
Access Test

scholarly journals Sensor-driven, human-in-the-loop lighting control

2017 ◽  
Vol 50 (5) ◽  
pp. 660-680 ◽  
Author(s):  
F Tan ◽  
D Caicedo ◽  
A Pandharipande ◽  
M Zuniga
Keyword(s):  
Control System ◽  
Visible Light ◽  
Visible Light Communication ◽  
User Preferences ◽  
Sensor Data ◽  
Test Bed ◽  
Lighting Control ◽  
Human In The Loop ◽  
Light Sensor ◽  
Lighting Systems

Smart indoor lighting systems use occupancy and light sensor data to adapt artificial lighting in accordance with changing occupancy and daylight conditions. Such systems can be designed to reduce lighting energy consumption significantly. However, these systems cannot account for individual user preferences at the workplace in real time. We propose a sensor-driven, human-in-the-loop lighting system that incorporates user feedback in addition to occupancy and light sensor inputs. In this system, luminaires transmit unique visible light communication identifier signals. By processing the image captured by a smartphone camera, a user obtains two pieces of information: visible light communication identifiers of luminaires in the vicinity and average image pixel value. A control algorithm is designed that incorporates these user inputs along with occupancy and light sensor inputs to determine the dimming levels of the luminaires to achieve illumination levels acceptable to users. We compare the performance of the proposed lighting control system with a sensor-driven lighting control system in an office test bed.

scholarly journals A Novel 3D Visible Light Positioning Method Using Received Signal Strength for Industrial Applications

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1311 ◽  
Author(s):  
Yousef Almadani ◽  
Muhammad Ijaz ◽  
Wout Joseph ◽  
Sander Bastiaens ◽  
Sujan Rajbhandari ◽  
...  
Keyword(s):  
Visible Light ◽  
Cost Function ◽  
Three Dimensional ◽  
Signal Strength ◽  
Received Signal Strength ◽  
Industrial Applications ◽  
Linear Least Squares ◽  
Test Bed ◽  
Positioning Method ◽  
Simulation Results

In this paper, a novel three-dimensional (3D) indoor visible light positioning (VLP) algorithm using the Cayley–Menger determinant (CMD) with a cost function is proposed and experimentally tested to track a drone for industrial applications. The proposed algorithm uses optical received signal strength (RSS) for estimating the drone’s 3D position without prior knowledge of its height. This reduces the need for additional height sensors used in some 3D VLP systems. The performance of the proposed algorithm in terms of positioning error is also compared with a linear least squares (LLS) trilateration algorithm, with and without tilting of the receiver and with multipath reflections. The simulation results show that the proposed algorithm is more accurate and outperforms the LLS algorithm by a median improvement of 21% and is also more robust to the effect of tilting, as well as in the presence of multipath reflections. Furthermore, the proposed algorithm has been experimentally tested and compared with the LLS algorithm in a VLP test bed measuring 4 × 4 × 4.1 m 3 . The experimental results show that the median errors for LLS are 11.4 cm, while the median errors for CMD are 10.5 cm, which results in an error decrease of 8% when CMD with a cost function is used.

scholarly journals Secure Visible Light Communication Technique Based on Asymmetric Data Encryption for 6G Communication Service

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1847
Author(s):  
Yong Up Lee
Keyword(s):  
Visible Light ◽  
Estimation Error ◽  
Visible Light Communication ◽  
Data Encryption ◽  
Easy Access ◽  
Test Bed ◽  
Error Performance ◽  
Real Experiment ◽  
Communication Technique ◽  
Asymmetric Encryption

Security in residential and business establishments has become an area of considerable importance. To provide enhanced security using conventional visible light (VL) communication, the characteristics of which allow for easy access by nearby intruders, a new VL communication technique is proposed in this paper. The novel VL communication system is based on a data encryption method using asymmetric encryption, and it is proposed for use in smart indoor services in the 6th generation communication environment. The asymmetric encryption capability is studied by comparison with the conventional technique, the optimum key length for the public or private encryption codes is determined under the criterion of the minimum estimation error. Moreover, the error performance is analyzed with various RSA encryption keys and data lengths to verify the performance of the proposed technique. A real experiment is performed to evaluate the proposed technique using an implemented test bed, and the success rates of the VL communication technique with and without RSA coding are evaluated by a real experiment with a test bed under an indoor laboratory VL channel. We believe it is evident that the VL communication technique based on asymmetric encryption yields superior error performance compared to that without encryption for optimal lengths of the encryption key and data bits.

scholarly journals Towards a 100 Gb/s visible light wireless access network

2015 ◽  
Vol 23 (2) ◽  
pp. 1627 ◽  
Author(s):  
Dobroslav Tsonev ◽  
Stefan Videv ◽  
Harald Haas
Keyword(s):  
Visible Light ◽  
Access Network ◽  
Wireless Access ◽  
Wireless Access Network

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

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