Modulations for Visible Light Communications With Dimming Control

Lee, Kwonhyung; Park, Hyuncheol

doi:10.1109/lpt.2011.2157676

Cited by 224 publications

(138 citation statements)

References 4 publications

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“…The light should be dimmable arbitrarily in VLC systems, without the communications becoming interrupted, which means that the data should be modulated in such a way that any desired level of dimming is supported [14]. Numerous valuable modulation schemes supporting dimming control have been proposed for the LEDs, such as the variable OOK [48], [72], variable PPM [73], pulse width modulation with DMT [74], etc. When the light intensity changes, it should be flickering above the human eyes' fusion frequency, so that the human eye cannot perceive it.…”

Section: Phy Techniques 1) Modulation Schemesmentioning

confidence: 99%

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

Zhang

Hanzo

2018

IEEE Commun. Surv. Tutorials

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Abstract-In order to counteract the explosive escalation of wireless tele-traffic, the communication spectrum has been gradually expanded from the conventional radio frequency (RF) band to the optical wireless (OW) domain. By integrating the classic RF band relying on diverse radio techniques and optical bands, the next-generation heterogeneous networks (HetNets) are expected to offer a potential solution for supporting the ever-increasing wireless tele-traffic. Owing to its abundant unlicensed spectral resources, visible light communications (VLC) combined with advanced illumination constitute a competent candidate for complementing the existing RF networks. Although the advantages of VLC are multi-fold, some challenges arise when incorporating VLC into the classic RF HetNet environments, which may require new system architectures. The user-centric (UC) design principle for VLC environments constitutes a novel and competitive design paradigm for the super dense multi-tier cell combinations of HetNets. The UC concept may be expected to become one of the disruptive techniques to be used in the forthcoming fifthgeneration era. This paper provides a comprehensive survey of visible-light-aided OW systems with special emphasis on the design and optimization of VLC networks, where the radically new UC design philosophy is reviewed. Finally, design guidelines are provided for VLC systems.

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Section: Phy Techniques 1) Modulation Schemesmentioning

confidence: 99%

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

Zhang

Hanzo

2018

IEEE Commun. Surv. Tutorials

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“…The original purpose of the lighting invokes an inherent constraint whereby the average optical intensity matches the dimming requirement imposed by a user. There have been a number of studies to achieve transmission techniques satisfying the constraint based on binary modulations [3][4][5][6], which are normally subject to limitations in the data rate. Therefore, the need for a higher data rate naturally leads to the use of multi-level modulations [7], 1) such as pulse-amplitude modulation (PAM), and poses a new challenge for efficient multi-level modulation adapting to the dimming requirement.…”

Section: Introductionmentioning

confidence: 99%

Convex Optimization Approach to Multi-Level Modulation for Dimmable Visible Light Communications under LED Efficiency Droop

Lee

Park

Kwon

2016

Journal of the Optical Society of Korea

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This paper deals with a design method and capacity loss of an efficient multi-level modulation scheme for dimmable visible light communications (VLC) systems that use light-emitting diodes (LEDs) with efficiency droop. To this end, the impact of such an impairment on dimmable VLC is addressed with respect to multi-level modulations based on pulse-amplitude modulation (PAM) via data-rate optimization formulation.

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“…Multicoded VPPM [29] adopts cyclic M-ary PPM for higher rates. Time-multiplexed OOK [26,30] was developed to insert an ON or OFF time period without adaptive control of the mean optical power. Inverse source coding (ISC) was reported to outperform the time-multiplexed OOK and achieve the theoretical data rate bound asymptotically in a noise-free environment [31,32].…”

Section: Introductionmentioning

confidence: 99%

“…Inverse source coding (ISC) was reported to outperform the time-multiplexed OOK and achieve the theoretical data rate bound asymptotically in a noise-free environment [31,32]. Multiple PPM was proposed to have as much rate support as ISC [30,33,34]. Color-shift keying (CSK) [26,35,36] positions the signal constellation according to color and controls dimming by the signal amplitude (optical power) for multicolored VLC.…”

Section: Introductionmentioning

confidence: 99%

Optimal Signal Amplitude of Orthogonal Frequency-Division Multiplexing Systems in Dimmable Visible Light Communications

Yun

Lee

Ahn

et al. 2014

Journal of the Optical Society of Korea

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Visible light communications (VLC) using the intensity modulation of light-emitting diodes (LEDs) provides a new communication medium to overcome the shortage of radio spectrum, and allows reuse of LED lighting infrastructures. Orthogonal frequency-division multiplexing (OFDM) was introduced to VLC for its merits in mitigating the fading effects resulting from delay spread, and in avoiding low-frequency ambient interference. Noise and clipping are two major factors that degrade the performance of OFDM in VLC. A larger signal easily overcomes noise, but experiences impairment by clipping. Therefore, degradation due to clipping has a trade-off relationship with that due to noise, depending on the signal amplitude of OFDM. In this paper, the optimal signal amplitude in the trade-off is obtained by simulation when the dimming and LED intensity are given. The former indicates a user's requirement for lighting, and the latter represents the channel quality. The required LED intensity-to-noise ratio, as the channel quality that guarantees dimming as well as an adequate bit-error rate (BER), is also discussed.

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Modulations for Visible Light Communications With Dimming Control

Cited by 224 publications

References 4 publications

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

Optimization of Visible-Light Optical Wireless Systems: Network-Centric Versus User-Centric Designs

Convex Optimization Approach to Multi-Level Modulation for Dimmable Visible Light Communications under LED Efficiency Droop

Optimal Signal Amplitude of Orthogonal Frequency-Division Multiplexing Systems in Dimmable Visible Light Communications

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