1.1-Gb/s White-LED-Based Visible Light Communication Employing Carrier-Less Amplitude and Phase Modulation

Wu, Fang–Jing; Lin, Chun-Ting; Wei, Chia-Chien; Chen, Cheng-Wei; Huang, H. W.; Ho, Chun-Hung

doi:10.1109/lpt.2012.2210540

Cited by 114 publications

(54 citation statements)

References 10 publications

(11 reference statements)

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“…However, in 2012, Wu and others [7] suggested to built a pair of orthogonal base-band signals starting from a root-raised cosine pulse ψ 1 (t). This pulse and its Hilbert-transform ψ 2 (t), shown in Fig.…”

Section: Icton 2015mentioning

confidence: 99%

“…Figure 2. (a) Root-raised cosine pulse with r = 0.5 and its Hilbert-transform to be used for CAP [7]; (b) corresponding cross power spectral density…”

Section: Icton 2015mentioning

confidence: 99%

“…We rather consider DC-biased DMT with bit-loading and block transmission with FDE based on PAM combined with line coding, on partial-response coding or on SSC modulation. The applicability of CAP transmission as suggested by Wu [7], where a pair of orthogonal baseband pulses shall be generated by means of a Hilbert transform, is also studied in the context of linear equalization. Section 2 discusses basic modeling aspects.…”

Section: Introductionmentioning

confidence: 99%

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Transmission schemes for visible light communications in multipath environments

Wolf

Cheema

Khalighi

et al. 2015

2015 17th International Conference on Transparent Optical Networks (ICTON)

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Discrete multitone transmission (DMT) is a useful approach to cope with the dispersive nature of VLC indoor channels. In such environments, the dispersion occurs either due to the LED in combination with its driver and or the multipath propagation channel. In this paper, we consider the impact of both types of dispersions on the bit error rate performance of a DMT based Li-Fi system. However, the main goal of this work is to compare the DMT scheme results with the transmission strategies employing frequency domain equalization. Here, we distinguish between pulse-amplitude modulation (PAM), partial-response coding, single-subcarrier (SSC) modulation, and "carrier-less amplitude and phase" (CAP) modulation. Keywords: visible light communication (VLC), Li-Fi, orthogonal frequency division multiplex (OFDM), discrete multitone transmission (DMT), block transmission, frequency domain equalization (FDE), wireless infrared (IR) transmission, polymer optical fiber (POF) communication, DC-balanced codes, partial-response coding INTRODUCTIONVisible light communication (VLC) uses the visible light portion of the electromagnetic spectrum to transmit data. It has become more and more attractive, since the LED lighting sources in homes, workplaces, factories or streets can additionally be used for wireless communication. Meanwhile, Li-Fi is an accepted term to describe this Wi-Fi analogy.In this work, we focus on the comparison of suitable transmission schemes for VLC based Li-Fi systems. Specifically, we consider only transmission schemes which ensure a DC-balance and thus a constant, data independent brightness, or schemes which can be easily combined with DC-balanced line codes. In order to take into account the bandwidth limitation caused by the LED in combination with its driver, we employ a Gaussian low-pass filter model at the transmitter. We do not claim that this model is generally valid, but the measurement results presented in [1] suggest rather a steep than a gradually roll-off beyond the upper cut-off frequency, which is said to be between 60 MHz and 180 MHz for a common high-power phosphorescent white-light LED with an optimized driver [1]. We also consider the effect of multipath propagation, if several spatially separated LEDs are used for illumination. Here we use simulated impulse responses, where high order diffuse reflections have been also taken into account.Discrete multitone transmission (DMT) is a promising approach to cope with the bandwidth limitation of the LED/LED-driver combo [2, 3]. Here we consider DC-biased DMT, since it inherently provides a DC-balance. DMT can be interpreted as a real valued variant of orthogonal frequency division multiplex (OFDM), where no quadrature up-conversion takes place after the inverse fast Fourier transform (IFFT) and digital-to-analog conversion at the transmitter. For VLC, it is impossible to modulate the field of a pair of sinusoidal high frequency (optical) carriers with a 90 • phase shift, since the LED-light source is strongly non-coherent. The optical field ap...

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Section: Icton 2015mentioning

confidence: 99%

“…Figure 2. (a) Root-raised cosine pulse with r = 0.5 and its Hilbert-transform to be used for CAP [7]; (b) corresponding cross power spectral density…”

Section: Icton 2015mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Transmission schemes for visible light communications in multipath environments

Wolf

Cheema

Khalighi

et al. 2015

2015 17th International Conference on Transparent Optical Networks (ICTON)

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“…In practical deployment, the RDM is recommended to be employed with other advanced modulation and multiplexing mechanisms [4,6,9].…”

Section: Experiments and Performance Analysismentioning

confidence: 99%

“…Besides the advanced modulation schemes [4][5][6], multiplexing techniques are also basic methods to increase the system speed and network capacity. Many multiplexing mechanisms have been utilized in current wireless communication such as time-division-multiplexing (TDM), code-divisionmultiplexing, and space-division-multiplexing (SDM).…”

mentioning

confidence: 99%

Efficient Cross-Room Switch Mechanism for Indoor Room-Division-Multiplexing Based Visible Light Communication Network

Huang

Xiong

et al. 2015

Journal of the Optical Society of Korea

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Visible light communication (VLC) is considered to be an attractive scheme to realize the broadband wireless communication for an indoor environment. We present a room division multiplexing (RDM) mechanism for an indoor multi-room VLC network, which utilizes the spatial position of the LED lamp in different rooms as a novel dimension of network resource for multiplexing, and thus the network capacity is increased. In such a network, the service interruption caused by user cross-room movement is an important problem, and we propose a double-area-positioning based cross-room switch solution. An experimental platform demonstrates the RDM-deployed VLC network, and validates the performance of the presented switch mechanism.

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