A Gigabit/s Indoor Wireless Transmission Using MIMO-OFDM Visible-Light Communications
TL;DR: An experimental demonstration of indoor wireless visible-light communication transmission at 1 Gb/s is reported, using a four-channel multiple-input multiple-output link that uses white LED sources.
Abstract: This letter reports an experimental demonstration of indoor wireless visible-light communication transmission at 1 Gb/s. The system consists of a four-channel multiple-input multiple-output link that uses white LED sources, each transmitting signals at 250 Mb/s using orthogonal frequency division multiplexing modulation. A nine-channel imaging diversity receiver is used to detect the signals, and an average bit error rate of 10-3 is achieved at the room illumination level of ~1000 lux at 1-m range.
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TL;DR: An in-depth view of Terahertz Band (0.1-10 THz) communication, which is envisioned as a key technology to satisfy the increasing demand for higher speed wireless communication, is provided.
1,206 citations
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
Cites background or methods from "A Gigabit/s Indoor Wireless Transmi..."
...In experimental demonstrations, speed of 1 Gb/s was achieved using 9 receivers [98]....
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...1 Gb/s with 4 transmitters and 9 receivers [98]....
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...In MIMO systems, even though in recent times progress has been made [97], [98], [102], [104], several system issues are yet...
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...MIMO processing can relax the requirement of terminal mobility and precise mechanical alignment [98]....
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...would impinge on a single receiver, which would require a static, precise alignment [98]....
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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
Cites background or methods from "A Gigabit/s Indoor Wireless Transmi..."
...It is possible to obtain a real OFDM signal by imposing Hermitian symmetry in the IFFT operation during the signal generation step [2], [3]....
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...A bipolar OFDM signal can be employed in an IM/DD system if a suitable DC-bias is applied [2], [3]....
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TL;DR: Current achievements and trends in high-speed indoor visible light communication (VLC) research are presented and for the first time, a bidirectional real-time VLC prototype achieving data rates of up to 500 Mb/s is presented.
Abstract: This article presents recent achievements and trends in high-speed indoor visible light communication (VLC) research. We address potential applications and future visions for the VLC technology, where transport of information is “piggybacked” on the original lighting function of LED-based lamps. To mature this technology and transfer it into practice, our recent research is focused on real-time implementation and trials. For the first time, a bidirectional real-time VLC prototype achieving data rates of up to 500 Mb/s is presented. This system paves the way for future real world applications. Finally, we discuss the remaining technical challenges as well as the research outlook in the field of high-speed VLC systems.
420 citations
Book•
12 Mar 2015TL;DR: This book provides a comprehensive analysis of information rate-, spectral- and power-efficiencies for single and multi-carrier transmission schemes, and a novel analysis of non-linear signal distortion, enabling the use of off-the-shelf LED technology.
Abstract: Balancing theoretical analysis and practical advice, this book describes all the underlying principles required to build high performance indoor optical wireless communication (OWC) systems based on visible and infrared light, alongside essential techniques for optimising systems by maximising throughput, reducing hardware complexity and measuring performance effectively. It provides a comprehensive analysis of information rate-, spectral- and power-efficiencies for single and multi-carrier transmission schemes, and a novel analysis of non-linear signal distortion, enabling the use of off-the-shelf LED technology. Other topics covered include cellular network throughput and coverage, static resource partitioning via dynamic interference-aware scheduling, realistic light propagation modelling, OFDM, optical MIMO transmission and nonlinearity modelling. Covering practical techniques for building indoor optical wireless cellular networks supporting multiple users and guidelines for 5G cellular system studies, in addition to physical layer issues, this is an indispensable resource for academic researchers, professional engineers and graduate students working in optical communications.
308 citations
References
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Journal Article•
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TL;DR: An analytical approach for symbol error ratio (SER) analysis of the SM algorithm in independent identically distributed Rayleigh channels results closely match and it is shown that SM achieves better performance in all studied channel conditions, as compared with other techniques.
Abstract: Spatial modulation (SM) is a recently developed transmission technique that uses multiple antennas. The basic idea is to map a block of information bits to two information carrying units: 1) a symbol that was chosen from a constellation diagram and 2) a unique transmit antenna number that was chosen from a set of transmit antennas. The use of the transmit antenna number as an information-bearing unit increases the overall spectral efficiency by the base-two logarithm of the number of transmit antennas. At the receiver, a maximum receive ratio combining algorithm is used to retrieve the transmitted block of information bits. Here, we apply SM to orthogonal frequency division multiplexing (OFDM) transmission. We develop an analytical approach for symbol error ratio (SER) analysis of the SM algorithm in independent identically distributed (i.i.d.) Rayleigh channels. The analytical and simulation results closely match. The performance and the receiver complexity of the SM-OFDM technique are compared to those of the vertical Bell Labs layered space-time (V-BLAST-OFDM) and Alamouti-OFDM algorithms. V-BLAST uses minimum mean square error (MMSE) detection with ordered successive interference cancellation. The combined effect of spatial correlation, mutual antenna coupling, and Rician fading on both coded and uncoded systems are presented. It is shown that, for the same spectral efficiency, SM results in a reduction of around 90% in receiver complexity as compared to V-BLAST and nearly the same receiver complexity as Alamouti. In addition, we show that SM achieves better performance in all studied channel conditions, as compared with other techniques. It is also shown to efficiently work for any configuration of transmit and receive antennas, even for the case of fewer receive antennas than transmit antennas.
1,996 citations
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
"A Gigabit/s Indoor Wireless Transmi..." refers background in this paper
...Full room coverage and implementation is investigated in [14]....
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...Such MIMO and similar multiple transmitterreceiver configurations is an active area of research (see [1], [7]–[14])....
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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
"A Gigabit/s Indoor Wireless Transmi..." refers background in this paper
...However, VLC is constrained by the bandwidth of the LED sources used for illumination, and schemes such as equalization and complex modulation [2], [3] have to be used to increase data rates....
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...Orthogonal frequency division multiplexing (OFDM) has found favour for VLC [4], [5] because of the high SNR, low bandwidth characteristic of typical white-Light LED based systems [2], [3]....
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TL;DR: In this paper, the authors reported a visible-light wireless point-to-point communication link operating at 513 Mbit/s gross transmission rate (net M bit/s), where the bit error ratio of the uncoded data was smaller than for an illumination level of lx.
Abstract: We report a visible-light wireless point-to-point communication link operating at 513 Mbit/s gross transmission rate (net Mbit/s). The bit-error ratio of the uncoded data was smaller than for an illumination level of lx. The link was based on a commercial thin-film high-power phosphorescent white LED, an avalanche photo diode, and off-line signal processing of discrete multitone signals. Quadrature-amplitude modulation, bit- and power-loading, as well as symmetrical clipping were successfully employed in pushing the gross transmission rate beyond 500 Mbit/s. Adaptation of the clipping level increased the data rate only by 2%, while simulations predicted an enhancement of 20%. Obstacles towards higher data rates as well as potential remedies are discussed. We predicted that data rates of over 1 Gbit/s can be achieved with the same setup and under the same experimental conditions if these obstacles are overcome.
502 citations
"A Gigabit/s Indoor Wireless Transmi..." refers background or methods in this paper
...As is discussed in [6], illuminance is an important design parameter, and a level of ∼ 1000 lux is typical for indoor lighting....
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...A raw BER of 2×10−3 can be reduced to 2×10−16 with forward error correction (FEC) coding algorithm [19], and this level is taken as the “benchmark” in similar papers [6], [19], so it is used here....
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...Using a single chip blue-phosphor LED, a transmission rate at 513 Mb/s has been demonstrated at 1000 lux [6]....
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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
"A Gigabit/s Indoor Wireless Transmi..." refers background or methods in this paper
...After the MIMO demultiplexing process, the received signal is equalized in the time domain using a first-order equaliser [3] (TDE on the diagram), and transformed back to the frequency domain....
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...However, VLC is constrained by the bandwidth of the LED sources used for illumination, and schemes such as equalization and complex modulation [2], [3] have to be used to increase data rates....
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...Orthogonal frequency division multiplexing (OFDM) has found favour for VLC [4], [5] because of the high SNR, low bandwidth characteristic of typical white-Light LED based systems [2], [3]....
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