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
The Radio Frequency （RF） communication suffers from interference and high latency issues. Along with this, RF communication requires a separate setup for transmission and reception of RF waves. Overcoming the above ...The Radio Frequency （RF） communication suffers from interference and high latency issues. Along with this, RF communication requires a separate setup for transmission and reception of RF waves. Overcoming the above limitations, Visible Light Communication （VLC） is a preferred communication technique because of its high bandwidth and immunity to interference from electromagnetic sources. The revolution in the field of solid state lighting leads to the replacement of florescent lamps by Light Emitting Diodes （LEDs） which further motivates the usage of VLC. This paper presents a survey of the potential applications, architecture, modulation techniques, standardization and research challenges in VLC.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.
文摘The Radio Frequency （RF） communication suffers from interference and high latency issues. Along with this, RF communication requires a separate setup for transmission and reception of RF waves. Overcoming the above limitations, Visible Light Communication （VLC） is a preferred communication technique because of its high bandwidth and immunity to interference from electromagnetic sources. The revolution in the field of solid state lighting leads to the replacement of florescent lamps by Light Emitting Diodes （LEDs） which further motivates the usage of VLC. This paper presents a survey of the potential applications, architecture, modulation techniques, standardization and research challenges in VLC.
