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Design and implementation of LED-LED indoor visible light communication system
摘要： This paper investigates the experimental performance of LEDs as both photo-emitter and photoreceiver. In this work LED-LED link is established using BJT and MOSFET based drive circuits at transmitting side and resistor driver operated in photo-conductive mode is used at the receiver side. The LED response as transmitter and receiver is investigated at different operating frequencies with the distance of up to 20 cm and the data rate of 1 Mbps. The SNR values of 8 dB and 11 dB are obtained using BJT and MOSFET drivers respectively at a distance of 20 cm. Furthermore, six different color LEDs are tested on both sides of transceiver to determine the best performing pair. It is observed that the red color LEDs have good responses as a photodiode due to its long wavelength in the visible spectrum. However their performance is significantly effected by ambient noise. Moreover, the responsivity of the Red color LED operated as photoreceiver with respect to different biasing voltages is also experimentally measured and discussed.
关键词： Visible Light Communication,LED as Photo-receiver,LED as Photo-emitter,Indoor communication,Responsivity
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE Industry Applications Society Annual Meeting - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Industry Applications Society Annual Meeting - Evaluation of Bit Error Ratio in Differential Phase-Shift-Keying Modulation Applied to VLC LED Drivers
摘要： This work presents a binary differential phase-shift keying (DPSK) modulation technique for visible light communication (VLC) systems aimed at low to moderate data rate applications. VLC uses the modulated light of LEDs to transmit data wireless. Such feature is added into artificial lighting systems by controlling the light intensity of a source. However, in most cases, modulation capabilities for VLC are employed with the addition of extra power components, which may harm efficiency and cost standards. Therefore, single switch LED drivers are preferable to provide VLC along with average current regulation. They are standard low-cost solutions that are able to perform both functions providing a satisfactory efficiency. Hence, in this work, DPSK modulation is applied to a buck converter operating in continuous conduction mode at 250 kHz, providing a raw data rate of 125 kbps. DPSK is advantageous because it overcomes possible parameters changes at the converter, along with possible duty cycle changes given by the control system of the average current for lighting. Moreover, the system performance is evaluated by means of its bit error ratio (BER) over signal-to-noise ratio (SNR), in a line-of-sight setup with variable distances between transmitter and receiver, showing a good behaviour of a BER less than 10?3 for about 8.1 m in a 8.4 W LED load.
关键词： Switched Converter,Solid-State Lighting,Light Emitting Diode,Visible Light Communication
更新于2025-09-12 10:27:22
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Polarized monolithic white semipolar (20–21) InGaN light-emitting diodes grown on high quality (20–21) GaN/sapphire templates and its application to visible light communication
摘要： We demonstrate efficient, polarized and monolithic white semipolar (20–21) InGaN light-emitting diodes (LEDs) grown on high crystal quality 4-inch (20–21) GaN/sapphire template. Materials growth by metal-organic chemical vapor deposition (MOCVD) and characterization by atom probe tomography (APT) were carried out. The fabricated regular 0.1 mm2 size LEDs show a high electrical performance with an output power of 3.9 mW at 100 mA, an emission spectrum with two peaks located at 445 nm and 565 nm, a CIE point of (0.37, 0.42) and a polarization ratio of 0.30, which make them promising candidates for backlighting in liquid crystal displays (LCDs) application. Moreover, the fabricated square phosphor-free white μLED with size ranging from 20 to 60 μm, exhibit a high 3 dB modulation bandwidth of 660 MHz in the visible light communication (VLC) system, which benefits from the shorter carrier lifetime grown on the semipolar (20–21) plane. To our best knowledge, this is the first demonstration of monolithic white semipolar μLEDs in the VLC application, which can overcome the limitation of the slow frequency response of yellow phosphors converted commercial white LEDs. These results demonstrate the huge potentials to produce high efficiency monolithic white semipolar InGaN LEDs on cost-effective large area sapphire substrates.
关键词： Polarization,Light-emitting diodes,Atom probe tomography,Semipolar GaN,Visible light communication
更新于2025-09-12 10:27:22
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Investigation of LED Non-linearity on DCO-OFDM and ACO-OFDM in VLC Systems using Multichip RGB LEDs for Indoor Applications
摘要： The impact of the LED non-linearity on the Intensity Modulation Direct Detection (IM-DD) in the VLC using OFDM for white light generated using RGB LEDs for indoor applications is analyzed. This work extends the orders of harmonics for analysis and investigates the impact of this non-linearity issue on OFDM techniques. The wavelengths (Red, Green and Blue) are individually set at the LED and their induced photocurrent in a Si PD is calculated. The result shows that the wavelength corresponding to the 625nm induces 5dB and 3dB more power than 528nm and 458nm respectively. We choose 625nm as the OFDM signal carrier for transmission keeping the other two un-modulated. We compare the effects of the non-linearity of the LED on the two OFDM techniques- Asymmetrical clipped optical (ACO) and Direct current biased optical (DCO). Our simulation results show that the power of the 2nd and 3rd order intermodulation components for ACO-OFDM is 3dB lesser than DCO-OFDM. The required SNR for ACO-OFDM is found to be 3dB lesser as compared to DCO-OFDM. The clipping effect of the LED remains unchanged irrespective of the OFDM variation applied.
关键词： Visible Light Communication,White Light,ACO-OFDM,LED,DCO-OFDM,Non-Linear Distortion
更新于2025-09-12 10:27:22
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[IEEE 2019 3rd International Conference on Trends in Electronics and Informatics (ICOEI) - Tirunelveli, India (2019.4.23-2019.4.25)] 2019 3rd International Conference on Trends in Electronics and Informatics (ICOEI) - Performance analysis of LEDs in MIMO-OFDM based VLC indoor communication
摘要： The combination of Visible Light Communication (VLC) and Multiple-Input Multiple-Output (MIMO) is used for high-data-rate indoor wireless communications. Because the traditional RF communication systems are not capable of satisfying the growing wireless communication systems. The dual function of light-emitting diodes (LEDs), such as illumination and communication to evaluate while implementing MIMO-VLC system. The LED-based VLC system has several advantages such as security, cost-effectiveness and lack of interference. In this work, the VLC system is used in an indoor environment. The LED lamps are placed at the ceiling to provide ambient light which offers rich spatial resources for VLC. Here, various LEDs such as phosphor-converted led, organic led, micro led, RGB led and white led are used and the performance of LEDs are analyzed. The type of receiver used in the MIMO VLC system is Avalanche Photodiode Detector (APD). The performance of LED is analyzed by luminous flux, luminous efficacy, switching time, data rate and brightness.
关键词： luminous efficacy,Visible light communication,multiple-input multiple-output,data rate,light-emitting diodes
更新于2025-09-12 10:27:22
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[IEEE 2019 Global LIFI Congress (GLC) - Paris, France (2019.6.12-2019.6.13)] 2019 Global LIFI Congress (GLC) - A 5Gb/s $2\times 2$ MIMO Real-time Visible Light Communication System based on silicon substrate LEDs
摘要： In this paper, we propose and experimentally demonstrate a high-speed 2×2 MIMO real-time VLC system (64QAM-DMT) based 64QAM-Discrete Multi-Tone modulation. The system was achieved by utilizing field programmable gate arrays (FPGAs) and silicon substrate LEDs. The effect of attenuation of the attenuator in transmitter and receiver, the aperture diameter of the received signal, code rate and different modulation order have been investigated in our experiment. The experimental results show that our real-time VLC system can transmit over 2m distance for an overall 5Gb/s successfully.
关键词： Discrete Multi-Tone (DMT),Multiple-Input-Multiple-Output (MIMO),real-time Visible Light Communication (real-time VLC)
更新于2025-09-12 10:27:22
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P‐16.1: Study of Active Matrix Circuits Design for Micro‐LED displays and Visible Light Communications
摘要： Because Micro-LED is the current-driven device, there are usually two types of the matrix driving circuit, passive matrix driving circuit, and active matrix driving circuit. Comparing these two driving circuits, the active driving circuit can achieve better brightness uniformity, higher contrast and lower contrast. Therefore, most of Micro-LEDs use active matrix driving circuit. In this paper, a study of active matrix circuit design for Micro- LED displays and beyond display applications such as visible light communication will be reported. The pixel circuit integrates two parts of VLC together, the emitter and the receiver. When the LED is on, it can work as the emitter of VLC. When the LED is off, the photodetector can work as the receiver of the VLC. This can offer more varieties of the application, such as face-to-face data transmission, under-screen fingerprint identification and so on.
关键词： pixel circuit,Micro-LED display,visible light communication
更新于2025-09-12 10:27:22
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Optical Fiber and Wireless Communications || Fundamental Analysis for Visible Light Communication with Input‐Dependent Noise
摘要： Recently, visible light communication (VLC) has drawn much attention. In literature, the noise in VLC is often assumed to be independent of the input signal. This assumption neglects a fundamental issue of VLC: due to the random nature of photon emission in the lighting source, the strength of the noise depends on the signal itself. Therefore, the input-dependent noise in VLC should be considered. Given this, the fundamental analysis for the VLC with input-dependent noise is presented in this chapter. Based on the information theory, the theoretical expression of the mutual information is derived. However, the expression of the mutual information is not in a closed form. Furthermore, the lower bound of the mutual information is derived in a closed form. Moreover, the theoretical expression of the bit error rate is also derived. Numerical results verify the accuracy of the derived theoretical expressions in this chapter.
关键词： bit error rate,input-dependent noise,visible light communication,mutual information
更新于2025-09-12 10:27:22
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[IEEE IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society - Lisbon, Portugal (2019.10.14-2019.10.17)] IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society - Review of LED drivers for Visible Light Communication
摘要： Visible Light Communication (VLC) shows up as a trend for short range wireless networks, which comes as a promising breakthrough for industry. However, this technology still faces challenges on the technical side. In particular, the selection of the appropriate circuit driver to fulfill simultaneously both lighting and communication functions is a non-trivial task. This paper reviews driver solutions intended for VLC applications, summarizing published research according to a proposed classification. Additionally, switched mode circuits stand out among the current works, supporting low data rates with higher overall efficiency at greater power levels. On the other hand, linear power amplifiers are the preferred choice for high data rate systems.
关键词： Efficiency,VLC,Visible Light Communication,LED Drivers,Illumination
更新于2025-09-12 10:27:22
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Integrated color photodetectors in 40 nm standard CMOS technology
摘要： For the further integration of receivers in multi-color visible light communication systems, a novel color photodetector (PD) was designed and fabricated by using a 40 nm standard complementary metal oxide semiconductor (CMOS) process without any process modifications. The PD consists of CMOS photodiode and two-dimensional (2D) polysilicon subwavelength grating above the photodiode. The 2D polysilicon grating is controlled in structural parameters to realize color filtering, based on guided-mode resonance, for the first time in a standard CMOS process. Here three kinds of color PDs were designed to respond to the three primary colors. The measured results demonstrate that the color PDs exhibit wavelength selectivity in the visible range (400-700 nm) and the maximum peaks in the spectral response curves of them are at 660 nm (red), 585 nm (green) and 465 nm (blue), respectively. In addition, the added 2D polysilicon grating almost does not reduce the responsivity of the photodiodes.
关键词： two-dimensional polysilicon subwavelength grating,Color photodetector,visible light communication,complementary metal oxide semiconductor (CMOS)
更新于2025-09-12 10:27:22