Author
Grahame Faulkner
Bio: Grahame Faulkner is an academic researcher from University of Oxford. The author has contributed to research in topics: Visible light communication & Optical wireless. The author has an hindex of 36, co-authored 149 publications receiving 6222 citations.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, a non-imaging optical MIMO system does not perform properly at all receiver positions due to symmetry, but an imaging based system can operate under all foreseeable circumstances, and simulations show such systems can operate at several hundred Mbit/s, and up to G Bit/s in many circumstances.
Abstract: Solid-state lighting is a rapidly growing area of research and applications, due to the reliability and predicted high efficiency of these devices. The white LED sources that are typically used for general illumination can also be used for data transmission, and Visible Light Communications (VLC) is a rapidly growing area of research. One of the key challenges is the limited modulation bandwidth of sources, typically several MHz. However, as a room or coverage space would typically be illuminated by an array of LEDs there is the potential for parallel data transmission, and using optical MIMO techniques is potentially attractive for achieving high data rates. In this paper we investigate non-imaging and imaging MIMO approaches: a non-imaging optical MIMO system does not perform properly at all receiver positions due to symmetry, but an imaging based system can operate under all foreseeable circumstances. Simulations show such systems can operate at several hundred Mbit/s, and up to Gbit/s in many circumstances.
846 citations
TL;DR: In this article, the authors presented a visible light communication (VLC) system based on a single 50-μm gallium nitride light emitting diode (LED) with a 3-dB modulation bandwidth of at least 60 MHz.
Abstract: This letter presents a visible light communication (VLC) system based on a single 50- μm gallium nitride light emitting diode (LED). A device of this size exhibits a 3-dB modulation bandwidth of at least 60 MHz - significantly higher than commercially available white lighting LEDs. Orthogonal frequency division multiplexing is employed as a modulation scheme. This enables the limited modulation bandwidth of the device to be fully used. Pre- and postequalization techniques, as well as adaptive data loading, are successfully applied to achieve a demonstration of wireless communication at speeds exceeding 3 Gb/s. To date, this is the fastest wireless VLC system using a single LED.
680 citations
TL;DR: In this paper, a high-speed visible light communications link that uses a white-light light-emitting diode (LED) was described, and a data rate of 100 Mb/s was achieved using on-off keying non-return-to-zero modulation.
Abstract: This letter describes a high-speed visible light communications link that uses a white-light light-emitting diode (LED). Such devices have bandwidths of few megahertz, severely limiting the data rates of any communication system. Here, we demonstrate that by detecting only the blue component of the LED, and using a simple first-order analogue equalizer, a data rate of 100 Mb/s can be achieved using on-off keying nonreturn-to-zero modulation.
547 citations
08 Dec 2008
TL;DR: The basic components in visible light communications systems are outlined, the state of the art is reviewed and some of the challenges and possibilities for this new wireless transmission technique are discussed.
Abstract: Solid-state lighting is a rapidly developing field. White-light and other visible LEDs are becoming more efficient, have high reliability and can be incorporated into many lighting applications. Recent examples include car head-lights based on white LEDs, and LED illumination as an architectural feature. The prediction that general illumination will use white LEDs in the future has been made, due to the increased energy efficiency that such an approach may have. Such sources can also be modulated at high-speed, offering the possibility of using sources for simultaneous illumination and data communications. Such visible light communications (VLC) was pioneered in Japan, and there is now growing interest worldwide, including within bodies such as the Visible Light Communications Consortium (VLCC) and the Wireless World Research Forum (WWRF). In this paper we outline the basic components in these systems, review the state of the art and discuss some of the challenges and possibilities for this new wireless transmission technique.
402 citations
TL;DR: In this paper, the authors describe a link that uses 16 LEDs which are modulated using a resonant driving technique, creating an overall modulation bandwidth of 25 MHz, which is used to implement a 40-Mb/s nonreturn-to-zero on-off keying link which operates at low error rates, and also provides illumination at levels sufficient for a standard office environment.
Abstract: White light-emitting diodes (LEDs) are becoming widespread in commercial lighting applications, and there are predictions that they will be in common use in domestic applications in the future. There is also growing interest in using these devices for both illumination and communications. One of the major challenges in visible light communications is the low modulation bandwidth (BW) available from devices, which is typically several megahertz. In this letter, we describe a link that uses 16 LEDs which are modulated using a resonant driving technique, creating an overall BW of 25 MHz. This is used to implement a 40-Mb/s nonreturn-to-zero on-off keying link which operates at low error rates, and also provides illumination at levels sufficient for a standard office environment.
354 citations
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TL;DR: An up-to-date survey on FSO communication systems is presented, describing FSO channel models and transmitter/receiver structures and details on information theoretical limits of FSO channels and algorithmic-level system design research activities to approach these limits are provided.
Abstract: Optical wireless communication (OWC) refers to transmission in unguided propagation media through the use of optical carriers, i.e., visible, infrared (IR), and ultraviolet (UV) bands. In this survey, we focus on outdoor terrestrial OWC links which operate in near IR band. These are widely referred to as free space optical (FSO) communication in the literature. FSO systems are used for high rate communication between two fixed points over distances up to several kilometers. In comparison to radio-frequency (RF) counterparts, FSO links have a very high optical bandwidth available, allowing much higher data rates. They are appealing for a wide range of applications such as metropolitan area network (MAN) extension, local area network (LAN)-to-LAN connectivity, fiber back-up, backhaul for wireless cellular networks, disaster recovery, high definition TV and medical image/video transmission, wireless video surveillance/monitoring, and quantum key distribution among others. Despite the major advantages of FSO technology and variety of its application areas, its widespread use has been hampered by its rather disappointing link reliability particularly in long ranges due to atmospheric turbulence-induced fading and sensitivity to weather conditions. In the last five years or so, there has been a surge of interest in FSO research to address these major technical challenges. Several innovative physical layer concepts, originally introduced in the context of RF systems, such as multiple-input multiple-output communication, cooperative diversity, and adaptive transmission have been recently explored for the design of next generation FSO systems. In this paper, we present an up-to-date survey on FSO communication systems. The first part describes FSO channel models and transmitter/receiver structures. In the second part, we provide details on information theoretical limits of FSO channels and algorithmic-level system design research activities to approach these limits. Specific topics include advances in modulation, channel coding, spatial/cooperative diversity techniques, adaptive transmission, and hybrid RF/FSO systems.
1,749 citations
TL;DR: Bergh and P.J.Dean as discussed by the authors proposed a light-emitting diode (LEDD) for light-aware Diodes, which was shown to have promising performance.
Abstract: Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.
1,560 citations
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
TL;DR: This article aims at reviewing and summarizing recent advancements in OW communication, with the main focus on indoor deployment scenarios, including a discussion of challenges, potential applications, state of the art, and prospects.
Abstract: In recent years, interest in optical wireless (OW) as a promising complementary technology for RF technology has gained new momentum fueled by significant deployments in solid state lighting technology. This article aims at reviewing and summarizing recent advancements in OW communication, with the main focus on indoor deployment scenarios. This includes a discussion of challenges, potential applications, state of the art, and prospects. Related issues covered in this article are duplex transmission, multiple access, MAC protocols, and link capacity improvements.
1,162 citations
TL;DR: IEEE 802.15.7 supports high- data-rate visible light communication up to 96 Mb/s by fast modulation of optical light sources which may be dimmed during their operation by dimming adaptable mechanisms for flicker-free high-data-ratevisible light communication.
Abstract: Visible light communication refers to shortrange optical wireless communication using visible light spectrum from 380 to 780 nm. Enabled by recent advances in LED technology, IEEE 802.15.7 supports high-data-rate visible light communication up to 96 Mb/s by fast modulation of optical light sources which may be dimmed during their operation. IEEE 802.15.7 provides dimming adaptable mechanisms for flicker-free high-data-rate visible light communication.
953 citations