- 标题
- 摘要
- 关键词
- 实验方案
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[IEEE 2019 3rd International Conference on Recent Developments in Control, Automation & Power Engineering (RDCAPE) - NOIDA, India (2019.10.10-2019.10.11)] 2019 3rd International Conference on Recent Developments in Control, Automation & Power Engineering (RDCAPE) - DSP Based Photovoltaic Hardware Development for Controlling Voltage and Current
摘要： We are interested in optimizing transmit beamforming for a visible light communication multiuser system such that the achievable sum rate is maximized. We ?rst derive a closed-form sum rate expression via information-theoretic tools. Then, by further including light-emitting diode optical power constraints, we formulate the rate maximization problem in a mathematical optimization form. To address this dif?cult non-convex problem, we establish an iterative algorithm that exploits sequential parametric convex approximation. Compared with the existing zero-forcing beamforming strategies, the proposed approach does not restrict the co-channel interference to be zero, and thus achieves a higher sum rate, as is validated by simulations.
关键词： achievable rate maximization,Visible light communication (VLC),transmit beamforming
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Advances in Big Data, Computing and Data Communication Systems (icABCD) - Winterton, South Africa (2019.8.5-2019.8.6)] 2019 International Conference on Advances in Big Data, Computing and Data Communication Systems (icABCD) - A Sensor for Monitoring the Lifespan of Color-LEDs in Traffic Lights
摘要： This paper has explored an effective monitoring of Red, Green and Yellow colors using visible-light communication systems (VLC) as a backbone on traffic lights for easy detection of traffic control light colors in South Africa as well as African continent in context to the problem of consistency in the ON state of traffic control frequency information of detected colors is employed to determine their state for prompt response to the road users. The lifespan of each light emitting diode (LED) dies gradually due to constant heat in the ON-state thus leave some traffic lights not attended. This negligence is because of weak network monitoring techniques which result in vehicle-to-vehicle accidents (V2V), vehicle-to-pedestrian accidents (V2P) and vehicle-to-motorcycle (V2M) accidents. The researchers deploy a TCS3200 pixel color sensor to monitor the lifespan of each LED color in the traffic light and using their variation in frequency to yield the LEDs lifespan, linking them with one central network for display. This experiment guarantees the road users of a steady traffic light to regulate the passing of vehicles without any accident both in frost, high winds and raining season.
关键词： RGB LEDs,Visible light communication (VLC),intensity,CIE 1931
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE Wireless Communications and Networking Conference (WCNC) - Marrakesh, Morocco (2019.4.15-2019.4.18)] 2019 IEEE Wireless Communications and Networking Conference (WCNC) - A Robust and Energy Efficient NOMA-Enabled Hybrid VLC/RF Wireless Network
摘要： The present work investigates the performance of non-orthogonal multiple access (NOMA) in a hybrid visible light communication (VLC)/radio frequency (RF) wireless network. In particular, we investigate the energy efficiency of the proposed architecture assuming imperfect channel state information (CSI), which is a realistic assumption that is encountered in practical indoor and outdoor wireless communication scenarios. We demonstrate that the performance of the proposed scheme in terms of energy efficiency outperforms by four-fold the corresponding performance of its orthogonal frequency division multiple access (OFDMA) counterpart. In addition, it is shown that the energy efficiency of the proposed scheme is more robust to CSI errors and line of sight (LOS) variations than the OFDMA-based scheme, which appears to be more susceptible to the CSI error and the LOS availability probability. Finally, our findings reveal that the performance gain of NOMA over OFDMA in the considered hybrid VLC/RF setup is directly proportional to the probability of LOS availability. These results are expected to be useful in the efficient design and efficient operation of hybrid VLC/RF wireless systems.
关键词： Non-orthogonal multiple access (NOMA),Energy efficiency,Channel state information (CSI),Radio frequency (RF),Visible light communication (VLC),Hybrid wireless network
更新于2025-09-12 10:27:22
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Adaptive Thresholding Scheme for Demodulation of Rolling-Shutter Images Obtained in CMOS Image Sensor Based Visible Light Communications
摘要： Light-emitting-diode transmitter and complementary-metal–oxide–semiconductor (CMOS) image sensor receiver based visible light communication is a promising scheme for an optical wireless communication. During the demodulation of the rolling shutter pattern obtained from the CMOS image sensor Rx, due to the high signal fluctuation introduced by the uneven light exposure, special thresholding schemes are needed to correctly identify the data logic. In this work, we propose and demonstrate a modified adaptive scheme (MQA) for the demodulation of the rolling shutter pattern. Experimental bit-error-ratio (BER) measurements using different thresholding schemes at different illuminance are analyzed. The results show that the proposed MQA scheme can provide much lower BER, with similar process latencies when compared with other schemes.
关键词： visible light communication (VLC),Light emitting diode (LED),CMOS image sensor.
更新于2025-09-10 09:29:36
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Improved Joint Generalized Spatial Modulations for MIMO-VLC Systems
摘要： In this letter, we propose the computationally efficient constellation design algorithms for single-mode and dual-mode joint generalized spatial modulations (JGSMs) to improve the symbol error rate (SER) performance over highly correlated indoor visible light communication channels. Our simulation results show that the proposed joint and improved dual-mode JGSMs can offer a better SER performance than the proposed single-mode JGSM (SM-JGSM) and the conventional SM-JGSM, which are validated through the analytical bounds.
关键词： Correlated channels,multiple-input multiple-output (MIMO),visible light communication (VLC),joint generalized spatial modulation (JGSM)
更新于2025-09-10 09:29:36
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Convolution neural network-based time-domain equalizer for DFT-Spread OFDM VLC system
摘要： This paper presents a novel time-domain equalizer for visible light communication (VLC) system using machine learning (ML) method. In this work, we employ discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) as modem scheme and convolution neural network (CNN) as kernel processing unit of equalizer. After estimating channel state information (CSI) from training sequence, the proposed equalizer recovers transmitted symbols according to the estimated CSI. Numerical simulations indicate that the equalizer can significantly enhance bit error rate (BER) performance. For example, when signal-to-noise ratio (SNR) is 20dB and 16/32/64-quadrature amplitude modulation (QAM) is exploited, original BER is about 0.5 while the BER after recovery achieves 10?5, which is much lower than forward error correction (FEC) limit 3.8×10?3. This work promotes the application of ML in VLC domain. To the best of our knowledge, this is the first time a CNN-based equalizer has been explored.
关键词： Machine learning (ML),Discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM),Visible light communication (VLC),Convolution neural network (CNN)
更新于2025-09-10 09:29:36
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Outage of SEE-OFDM VLC-NOMA Networks
摘要： In this letter, an indoor spectrally and energy efficient orthogonal frequency division multiplexing (SEE-OFDM) based visible light communication (VLC) network with non-orthogonal multiple access (NOMA) is studied. An exact expression of the outage probability for K NOMA users is derived. We also provide an upper bound of the data rate of the SEE-OFDM VLC-NOMA network. Finally, the proposed system model shows its superiority compared to the orthogonal multiple access.
关键词： outage probability (OP),visible light communication (VLC),Non-orthogonal multiple access (NOMA)
更新于2025-09-10 09:29:36
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[IEEE 2018 11th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP) - Budapest (2018.7.18-2018.7.20)] 2018 11th International Symposium on Communication Systems, Networks & Digital Signal Processing (CSNDSP) - Performance Comparison of MIMO CAP Receivers in Visible Light Communication
摘要： Multiple-input, multiple-output (MIMO) techniques have recently been proposed to improve the spectral ef?ciency of the conventional carrierless amplitude and phase (CAP) implementation modulation scheme while maintaining its simplicity in visible light communication (VLC). The proposed MIMO CAP uses the optimum Maximum Likelihood (ML) detection scheme which has high computational complexity. As a result, four practical, low-complexity detection schemes are investigated for MIMO CAP in this work and their performances are compared with that of ML. It is found that the minimum mean square error detection with optimally-ordered successive interference cancellation (MMSE-OSIC) offers the best choice between complexity and bit-error rate (BER) performance. To achieve a spectral ef?ciency of 8 bits/s/Hz at BER of 10?4 in a 4 × 8 MIMO CAP system, the signal-to-noise ratio (SNR) requirement of the MMSE-OSIC is 5 dB higher than that of the optimum ML receiver. However, the ML receiver’s complexity is an order of magnitude higher than that of the MMSE-OSIC.
关键词： spatial multiplexing (SM),visible light communication (VLC),carrierless amplitude and phase modulation (CAP),optical communication,MIMO
更新于2025-09-09 09:28:46
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An Overview of OFDM-Based Visible Light Communication Systems From the Perspective of Energy Efficiency Versus Spectral Efficiency
摘要： In this paper, the energy ef?ciency and the spectral ef?ciency for orthogonal frequency division multiplexing (OFDM)-based visible light communication schemes are studied, which is crucial for practical application with limited energy resources. The conventional schemes, including asymmetrically clipped optical OFDM (ACO-OFDM), pulse-amplitude-modulated discrete multitone, and direct current biased optical OFDM, are compared in terms of energy ef?ciency and spectral ef?ciency relationship. The in?uence of power allocation for asymmetrically clipped dc biased optical OFDM and hybrid ACO-OFDM is also investigated. The energy ef?ciency and spectral ef?ciency of layered ACO-OFDM with a variable layer number are calculated and their relationship is also formulated. These conventional and hybrid modulation schemes are analyzed and compared through computer simulations, which should be considered in practice according to the requirements of illumination and transmission.
关键词： visible light communication (VLC),spectral ef?ciency,orthogonal frequency division multiplexing (OFDM),Energy ef?ciency
更新于2025-09-09 09:28:46
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Noise Analysis and Modeling in Visible Light Communication Using Allan Variance
摘要： Visible Light Communication (VLC) is a rising communication technology which uses Light-Emitting Diode (LED) luminaries for high-speed data transferring; however, the optical signal is usually degraded by the noise in the practical VLC system. In this article, Allan Variance is introduced for noise analysis and modeling in VLC for the first time, which provides an efficient method to measure different kinds of noise in the VLC systems. By applying Allan variance to analyze the signals collected from the real-world environment, both white noise and random walk are observed in the VLC systems. The observed white noise and random walk are also modeled by using the Allan variance. The noise analysis and modeling based on Allan variance provide a method to improve the performance of VLC.
关键词： Visible Light Communication (VLC),random walk,white noise,Allan Variance,time-correlated noise,photodiode
更新于2025-09-09 09:28:46