Modulation techniques for light fidelity （Li-Fi） are reviewed in this paper. Li-Fi is the fully networked solution for nmltiple users that combines communication and illumination simultaneously. Light emitting diod...Modulation techniques for light fidelity （Li-Fi） are reviewed in this paper. Li-Fi is the fully networked solution for nmltiple users that combines communication and illumination simultaneously. Light emitting diodes （LEDs） are used in Li-Fi as visible light transmitters, therefore, only intensity modulated direct detected modulation techniques can be achieved. Single carrier modulation techniques are straightforward to be used in Li-Fi, however, computationally complex equalization processes are required in fre- quency selective Li-Fi channels. On the other hand, multiearrier modulation techniques offer a viable solution for Li-Fi in terms of power, spectral and computational efficiency. In particular, orthogonal frequency division multiplexing （OFDM） based modulation techniques offer a practical solution for Li-Fi, especially when direct current （DC） wander, and adaptive bit and power loading techniques are considered. Li-Fi modulation techniques need to also satisfy illumination requirements. Flickering avoidance and dimming control are considered in the variant modulation techniques presented. This paper surveys the suitable modulation techniques for Li-Fi including those which explore time, frequency and colour domains.展开更多
The latest uproar in this era is about a technology termed as Light Fidelity or more commonly known as Li-Fi. There are currently two trends being seen: First, the extension or enrichment of wireless services and othe...The latest uproar in this era is about a technology termed as Light Fidelity or more commonly known as Li-Fi. There are currently two trends being seen: First, the extension or enrichment of wireless services and other being increased in user demand for these services, but the available RF spectrum for usage is very limited. So the new technology of Li-Fi came into picture, which uses visible light as a source of communication. Li-Fi is the most recent development which is resourceful. In this technology, LEDs are used to transmit data in the visible light spectrum. This technology can be compared with that of Wi-Fi and offers advantages like increased accessible spectrum, efficiency, security, low latency and much higher speed. This research paper aims at designing a Li-Fi transceiver using Arduino that is able to transmit digital data. The hardware has been designed using Eagle CAD (version 7.1.0) tool and Proteus design tool (version 8). The software coding is done by using Java (version 8). Successful transmission and reception of text, image and video signals is carried out on the transceiver. Hence this research work gives an innovative way of designing a transceiver which works by using off the shelf low cost components and using visible light spectrum.展开更多
Visible light communication （VLC） is an emerging technology in optical wireless communication （OWC） that has attracted worldwide research in recent years. VLC can combine communication and illumina- tion together,...Visible light communication （VLC） is an emerging technology in optical wireless communication （OWC） that has attracted worldwide research in recent years. VLC can combine communication and illumina- tion together, which could be applied in many application scenarios such as visible light communication local area networks （VLANs）, indoor localization, and intelligent lighting. In recent years, pioneering and significant work have been made in the field of VLC. In this paper, an overview of the recent progress in VLC is presented. We also demonstrate our recent experiment results including bidirectional 100 Mbit/s VLAN or Li-Fi system based on 00K modulation without blue filter. The VLC systems that we proposed are good solutions for high-speed VLC application systems with low-cost and low-complexity. VLC technology shows a bright future due to its inherent advantages, shortage of RF spectra and ever increasing popularity of white LEDs.展开更多
基金support by the UK Engineering and Physical Sciences Research Council(EPSRC)under Grants EP/K008757/1 and EP/M506515/1
文摘Modulation techniques for light fidelity （Li-Fi） are reviewed in this paper. Li-Fi is the fully networked solution for nmltiple users that combines communication and illumination simultaneously. Light emitting diodes （LEDs） are used in Li-Fi as visible light transmitters, therefore, only intensity modulated direct detected modulation techniques can be achieved. Single carrier modulation techniques are straightforward to be used in Li-Fi, however, computationally complex equalization processes are required in fre- quency selective Li-Fi channels. On the other hand, multiearrier modulation techniques offer a viable solution for Li-Fi in terms of power, spectral and computational efficiency. In particular, orthogonal frequency division multiplexing （OFDM） based modulation techniques offer a practical solution for Li-Fi, especially when direct current （DC） wander, and adaptive bit and power loading techniques are considered. Li-Fi modulation techniques need to also satisfy illumination requirements. Flickering avoidance and dimming control are considered in the variant modulation techniques presented. This paper surveys the suitable modulation techniques for Li-Fi including those which explore time, frequency and colour domains.
文摘The latest uproar in this era is about a technology termed as Light Fidelity or more commonly known as Li-Fi. There are currently two trends being seen: First, the extension or enrichment of wireless services and other being increased in user demand for these services, but the available RF spectrum for usage is very limited. So the new technology of Li-Fi came into picture, which uses visible light as a source of communication. Li-Fi is the most recent development which is resourceful. In this technology, LEDs are used to transmit data in the visible light spectrum. This technology can be compared with that of Wi-Fi and offers advantages like increased accessible spectrum, efficiency, security, low latency and much higher speed. This research paper aims at designing a Li-Fi transceiver using Arduino that is able to transmit digital data. The hardware has been designed using Eagle CAD (version 7.1.0) tool and Proteus design tool (version 8). The software coding is done by using Java (version 8). Successful transmission and reception of text, image and video signals is carried out on the transceiver. Hence this research work gives an innovative way of designing a transceiver which works by using off the shelf low cost components and using visible light spectrum.
基金supported by the National High Technology Research and Development Program of China(Nos.2015AA033303,2013AA013602,2013AA013603,2013AA03A104)the National Natural Science Foundation of China(Nos.61178051,61321063,61335010,61178048,61275169)the National Basic Research Program of China(Nos.2013CB329205,2011CBA00608)
文摘Visible light communication （VLC） is an emerging technology in optical wireless communication （OWC） that has attracted worldwide research in recent years. VLC can combine communication and illumina- tion together, which could be applied in many application scenarios such as visible light communication local area networks （VLANs）, indoor localization, and intelligent lighting. In recent years, pioneering and significant work have been made in the field of VLC. In this paper, an overview of the recent progress in VLC is presented. We also demonstrate our recent experiment results including bidirectional 100 Mbit/s VLAN or Li-Fi system based on 00K modulation without blue filter. The VLC systems that we proposed are good solutions for high-speed VLC application systems with low-cost and low-complexity. VLC technology shows a bright future due to its inherent advantages, shortage of RF spectra and ever increasing popularity of white LEDs.
