LI-FI
LI-FI
1.Coexistence of WiFi and LiFi toward 5G: Concepts, Opportunities, and Challenges
Coexistence of WiFi and LiFi toward 5G: Concepts, Opportunities, and Challenges
Abstract
Smart phones, tablets, and the rise of the Internet of Things are driving an insatiable demand for wireless capacity. This demand requires networking and Internet infrastructures to evolve to meet the needs of current and future multimedia applications. Wireless HetNets will play an important role toward the goal of using a diverse spectrum to provide high quality-of-service, especially in indoor environments where most data are consumed. An additional tier in the wireless HetNets concept is envisioned using indoor gigabit small-cells to offer additional wireless capacity where it is needed the most. The use of light as a new mobile access medium is considered promising. In this article, we describe the general characteristics of WiFi and VLC (or LiFi) and demonstrate a practical framework for both technologies to coexist. We explore the existing research activity in this area and articulate current and future research challenges based on our experience in building a proof-of-concept prototype VLC HetNet.
2.Experimental Biomedical EEG Signal Transmission Using VLC
Experimental Biomedical EEG Signal Transmission Using VLC
Abstract
The proliferation of radio frequency (RF) communication technology in biomedical signal transmission is frequently flustered by electromagnetic interference. Even though the flexibility and mobility of RF-based communication have much attraction, the radiation brings damage to hospital equipments and even harm to humans. In this letter, we propose a novel scheme for transmission of electroencephalography (EEG) biomedical signal using a visible light communication (VLC) link. The data transmission is performed in line of sight (LOS) condition using ON–OFF keying non return-to-zero modulation by utilizing all three components, red, green, and blue, of RGB LED. Experiments are carried out for transmitting EEG signals using the VLC link. The transmitter consists of RGB LEDs, and at the receiver side, three photodiodes with red, green, and blue color filters are installed. The experimental results show excellent reliability and accuracy of the proposed scheme.
3.Impact of VLC on Light Emission Quality of White LEDs
Impact of VLC on Light Emission Quality of White LEDs
Abstract
This paper reports the effect of data modulation on the emitted light quality of phosphor converted white LEDs. The results showed that provided the expected average current driving the LEDs remains unchanged then the emitted light quality will stay the same. For a DC-balanced modulating signal, with a non-varying average value, any fluctuations in the instantaneous driving current due to data modulation do not have any significant impact on the measured light quality metrics. For visible light communication applications therefore, a DC-balanced signalling becomes a prerequisite if the expected quality of light emitted by the LEDs is to be preserved. The findings are premised on adequate thermal management for the LEDs under test.
4.Implementation of ZigBee-VLC system to support light control network configuration
Implementation of ZigBee-VLC system to support light control network configuration
Abstract
In this paper, ZigBee-VLC Transmitter and Receiver are designed, implemented and tested. By utilizing the ZigBee- VLC Transmitter and Receiver, commissioning procedures for light control network configuration are simplified and commissioning time is drastically reduced. With this configuration, lighting control network configured to use a maximum of 216 lighting is possible. As a result of this research, the transmitter is complete with ZigBee-VLC features implemented in the Single MCU without rising production costs and the 1-board solution receiver including a ZigBee and VLC functions are implemented. In addition, as a result of the test work using the light control app, dramatically shortening commissioning time, easy lighting control is possible was confirmed.
4.Implementation of ZigBee-VLC system to support light control network configuration
Implementation of ZigBee-VLC system to support light control network configuration
Abstract
In this paper, ZigBee-VLC Transmitter and Receiver are designed, implemented and tested. By utilizing the ZigBee- VLC Transmitter and Receiver, commissioning procedures for light control network configuration are simplified and commissioning time is drastically reduced. With this configuration, lighting control network configured to use a maximum of 216 lighting is possible. As a result of this research, the transmitter is complete with ZigBee-VLC features implemented in the Single MCU without rising production costs and the 1-board solution receiver including a ZigBee and VLC functions are implemented. In addition, as a result of the test work using the light control app, dramatically shortening commissioning time, easy lighting control is possible was confirmed.
5.Stereo Audio Streaming via Visible Light
Stereo Audio Streaming via Visible Light
Abstract
Visible Light Communication (VLC) is emerging as a next generation data transmission method for short-range communication applications. In this paper we implement and characterize two prototype stereo audio streaming methods utilizing VLC. Software architecture is developed to process and stream data. The software architecture is bridged with a hardware section, which facilitates free-space VLC channel, over a Universal Serial Bus (USB) to serial interface. A particularly attractive feature of our system is that it uses commonly available, low-cost components which enable its implementation in everyday applications.
6.Uncoordinated Multiple Access Scheme for VLC Systems with Positioning Capability
Uncoordinated Multiple Access Scheme for VLC Systems with Positioning Capability
Abstract
Visible light communication (VLC) has attracted a lot of attention in past several years. VLC systems can be used for both communications and indoor positioning. Several designs of VLC systems have been proposed and most of them require central units to control the light emitting diodes (LEDs) in the transmitters to avoid interference at the receiver side. In this paper, we propose a novel multiple access schemes for VLC systems that does not require central unit. The transmitters simultaneously broadcast different information. The receiver can extract the information from the superposition of the received signals from the transmitters. The received power from individual transmitters can also be determined at the receiver so that positioning algorithms can be applied. Simulation results show that our proposed scheme outperforms existing multiple access schemes for VLC systems without central unit.