Visible light communication using OFDM
05 Jul 2006-pp 129-134
TL;DR: It is demonstrated theoretically and by means of an experimental system that the high peak-to-average ratio in OFDM can be exploited constructively in visible light communication to intensity modulate LEDs.
Abstract: In this paper wireless communication using white, high brightness LEDs (light emitting diodes) is considered. In particular, the use of OFDM (orthogonal frequency division multiplexing) for intensity modulation is investigated. The high peak-to-average ratio (PAR) in OFDM is usually considered a disadvantage in radio frequency transmission systems due to non-linearities of the power amplifier. It is demonstrated theoretically and by means of an experimental system that the high PAR in OFDM can be exploited constructively in visible light communication to intensity modulate LEDs. It is shown that the theoretical and the experimental results match very closely, and that it is possible to cover a distance of up to one meter using a single LED.
Citations
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TL;DR: This survey provides a technology overview and review of existing literature of visible light communication and sensing and outlines important challenges that need to be addressed in order to design high-speed mobile networks using visible light Communication-VLC.
Abstract: The solid-state lighting is revolutionizing the indoor illumination. Current incandescent and fluorescent lamps are being replaced by the LEDs at a rapid pace. Apart from extremely high energy efficiency, the LEDs have other advantages such as longer lifespan, lower heat generation, and improved color rendering without using harmful chemicals. One additional benefit of LEDs is that they are capable of switching to different light intensity at a very fast rate. This functionality has given rise to a novel communication technology (known as visible light communication—VLC) where LED luminaires can be used for high speed data transfer. This survey provides a technology overview and review of existing literature of visible light communication and sensing. This paper provides a detailed survey of 1) visible light communication system and characteristics of its various components such as transmitter and receiver; 2) physical layer properties of visible light communication channel, modulation methods, and MIMO techniques; 3) medium access techniques; 4) system design and programmable platforms; and 5) visible light sensing and application such as indoor localization, gesture recognition, screen-camera communication, and vehicular networking. We also outline important challenges that need to be addressed in order to design high-speed mobile networks using visible light communication.
1,208 citations
Cites background from "Visible light communication using O..."
...Similarly, authors of [142] demonstrated the implementation of ACO-OFDM and DCO-OFDM for VLC using the WARP boards....
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...Depending on how the bipolar signals are converted to unipolar, there are two types of OFDM techniques: 1) AsymmetricallyClipped Optical OFDM (ACO-OFDM) and 2) DC-biased Optical OFDM (DCO-OFDM)....
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...Authors of [64] first proposed the use of OFDM for visible light communication....
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...[68] presented a comparison of both the OFDM schemes and showed that LED clipping distortion is more significant in DCO-OFDM compared to ACO-OFDM....
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...While in DCO-OFDM [64], [66], [67], all subcarriers are modulated but a positive direct current is added to make the signal unipolar....
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TL;DR: This paper will show how LiFi takes VLC further by using light emitting diodes (LEDs) to realise fully networked wireless systems to illustrate that LiFi attocells are not a theoretical concept any more, but at the point of real-world deployment.
Abstract: This paper attempts to clarify the difference between visible light communication (VLC) and light-fidelity (LiFi). In particular, it will show how LiFi takes VLC further by using light emitting diodes (LEDs) to realise fully networked wireless systems. Synergies are harnessed as luminaries become LiFi attocells resulting in enhanced wireless capacity providing the necessary connectivity to realise the Internet-of-Things, and contributing to the key performance indicators for the fifth generation of cellular systems (5G) and beyond. It covers all of the key research areas from LiFi components to hybrid LiFi/wireless fidelity (WiFi) networks to illustrate that LiFi attocells are not a theoretical concept any more, but at the point of real-world deployment.
760 citations
Cites background from "Visible light communication using O..."
...perhaps the most common realisation of MCM in LiFi networks is OFDM [15], [16], where parallel data streams are transmitted simultaneously through a collection of orthogonal subcarriers and complex equalization can be omitted....
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TL;DR: This paper provides a comprehensive survey on VLC with an emphasis on challenges faced in indoor applications over the period 1979-2014.
Abstract: Visible Light Communication (VLC) is an emerging field in Optical Wireless Communication (OWC) which utilizes the superior modulation bandwidth of Light Emitting Diodes (LEDs) to transmit data. In modern day communication systems, the most popular frequency band is Radio Frequency (RF) mainly due to little interference and good coverage. However, the rapidly dwindling RF spectrum along with increasing wireless network traffic has substantiated the need for greater bandwidth and spectral relief. By combining illumination and communication, VLC provides ubiquitous communication while addressing the shortfalls and limitations of RF communication. This paper provides a comprehensive survey on VLC with an emphasis on challenges faced in indoor applications over the period 1979–2014. VLC is compared with infrared (IR) and RF systems and the necessity for using this beneficial technology in communication systems is justified. The advantages of LEDs compared to traditional lighting technologies are discussed and comparison is done between different types of LEDs currently available. Modulation schemes and dimming techniques for indoor VLC are discussed in detail. Methods needed to improve VLC system performance such as filtering, equalization, compensation, and beamforming are also presented. The recent progress made by various research groups in this field is discussed along with the possible applications of this technology. Finally, the limitations of VLC as well as the probable future directions are presented.
687 citations
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TL;DR: Light-Fidelity takes visible light communication (VLC) further by using light emitting diodes (LEDs) to realise fully networked wireless systems for the Internet-of-Things (IoT), 5G and beyond.
Abstract: Light-Fidelity (LiFi) takes visible light communication (VLC) further by using light emitting diodes (LEDs) to realise fully networked wireless systems. Synergies are harnessed as lights become LiFi attocells resulting in enhanced wireless capacity for the Internet-of-Things (IoT), 5G and beyond.
527 citations
Cites background from "Visible light communication using O..."
...perhaps the most common realisation of MCM in LiFi networks is OFDM [15], [16], where parallel data streams are transmitted simultaneously through a collection of orthogonal subcarriers and complex equalization can be omitted....
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TL;DR: In this article, the authors investigate analytically and by Monte Carlo simulations feasible data transmission rates in a moderate-size office room, where the use of commercially available LEDs and photodiodes.
Abstract: Emergence of white-light LEDs allows the combination of lighting and information broadcast functionality in one optical source. We investigate analytically and by Monte Carlo simulations feasible data transmission rates in a moderate-size office room, where we assume illumination conforming to standards and the use of commercially available LEDs and photodiodes. The performances of systems relying on baseband [i.e., pulse-amplitude modulation (PAM)] and discrete multitone (DMT) transmission show that data rates of more than 100 Mbit/s can be expected despite the rather low bandwidth of the system.
492 citations
References
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31 Aug 1994TL;DR: The use of infrared radiation as a medium for high-speed short-range wireless digital communication, and several modification formats, including on-off keying (OOK), pulse-position modulation (PPM), and subcarrier modulation, are discussed.
Abstract: The use of infrared radiation as a medium for high-speed short-range wireless digital communication is discussed. Available infrared links and local-area networks are described. Advantages and drawbacks of the infrared medium are compared to those of radio and microwave media. The physical characteristics of infrared channels using intensity modulation with direct detection (IM/DD) are presented including path losses and multipath responses. Natural and artificial ambient infrared noise sources are characterized. Strategies for designs of transmitter and receivers that maximize link signal-to-noise ratio (SNR) are described. Several modification formats are discussed in detail, including on-off keying (OOK) pulse-position modulation (PPM), and subcarrier modulation. The performance of these techniques in the presence of multipath distortion is quantified. Techniques for multiplexing the transmissions of different users are reviewed. The performance of an experimental 50-Mb/s on-off-keyed diffuse infrared link is described.
2,972 citations
TL;DR: Based on numerical analyses, it is shown that the proposed indoor visible-light communication system utilizing white LED lights is expected to be the indoor communication of the next generation.
Abstract: White LED offers advantageous properties such as high brightness, reliability, lower power consumption and long lifetime. White LEDs are expected to serve in the next generation of lamps. An indoor visible-light communication system utilizing white LED lights has been proposed from our laboratory. In the proposed system, these devices are used not only for illuminating rooms but also for an optical wireless communication system. Generally, plural lights are installed in our room. So, their optical path difference must be considered. In this paper, we discuss about the influence of interference and reflection. Based on numerical analyses, we show that the system is expected to be the indoor communication of the next generation.
2,913 citations
"Visible light communication using O..." refers background in this paper
...OOK (on-off keying), PCM (pulse code modulation), and SC-BPSK (sub-carrier binary phase shift keying) are some of the more popular modulation schemes used in conjunction with LED wireless systems [1]....
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IBM1
TL;DR: In this paper, a novel wireless broadcast/multi-access channel for flexibly interconnecting a cluster of data terminals located within the same room is described, where the transmission medium is diffusively scattered infrared radiation at 950-nm wavelength.
Abstract: A novel wireless broadcast/multi-access channel is described for flexibly interconnecting a cluster of data terminals located within the same room. The transmission medium is diffusively scattered infrared radiation at 950-nm wavelength. Transmission is low-to-medium speed and the range up to 50 m. Theoretical analysis indicates that the time dispersion limits the transmission bandwidth of the system to 260 Mbit ċ m/s, but background noise produced by ambient daylight reduces the transmission speed below 1 Mbit/s. The transmission properties of the diffuse optical channel are analyzed, and experimental digital links for baseband PCM at 125 kbit/s and PSK 64 kbit/s are demonstrated.
1,060 citations
15 Apr 2003
TL;DR: In this article, the major optical design issues and communication design issues are discussed, along with a comparison of infrared systems to radio systems, and an overview of current systems and standards is provided.
Abstract: Wireless infrared communications can be used to establish short range high-data-rate wireless links. The primary commercial applications are short-term cable-less connectivity for information exchange and wireless local area networking. In the article, the major optical design issues and communication design issues are discussed. An overview of current systems and standards is provided, along with a comparison of infrared systems to radio systems.
Keywords:
wireless infrared communications;
channel modeling;
digital modulation;
IRDA
962 citations
TL;DR: A recursive method for evaluating the impulse response of an indoor free-space optical channel with Lambertian reflectors, which enables accurate analysis of the effects of multipath dispersion on high-speed indoor optical communication systems.
Abstract: A recursive method for evaluating the impulse response of an indoor free-space optical channel with Lambertian reflectors is presented. The method, which accounts for multiple reflections of any order, enables accurate analysis of the effects of multipath dispersion on high-speed indoor optical communication systems. A simple algorithm for computer implementation of the technique and computer simulation results for both line-of-sight and diffuse transmitter configurations are also presented. In both cases, it is shown that reflections of multiple order are a significant source of intersymbol interference. Experimental measurements of optical multipath, which help verify the accuracy of the simulations, are discussed. >
867 citations
"Visible light communication using O..." refers background or methods in this paper
...For the intensity-in intensity-out channel, this is the fraction of the power from a continuous wave transmitter that reaches the detector [3]....
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...Although an algorithm to derive the channel impulse response for multiple reflections is provided in [3], the influence of multiple reflections was neglected; as the 5μs guard in the OFDM symbols is more than enough to mitigate any multipath effects encountered....
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