• Title, Summary, Keyword: Visible light channel

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Short-range Visible Light Positioning Based on Angle of Arrival for Smart Indoor Service

  • Lee, Yong Up;Park, Seop Hyeong
    • Journal of Electrical Engineering and Technology
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    • v.13 no.3
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    • pp.1363-1370
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    • 2018
  • In visible light (VL) positioning based on angle of arrival (AOA) estimation for smart indoor service, the AOA parameters obtained at the receiver has sometimes a random and distributed angle form instead of a point angle form due to the multipath transfer of the actual visible light and short positioning distance. The AOA estimation of a VL signal with a random and parametric distributed angle form may give incorrect AOA parameter estimates, which may result in poor VL positioning performance. In this paper, we classify the AOA parameters of the received VL signal into three forms according to the actual positioning channel environment and consider the short-range VL positioning method. We propose a subspace-based AOA parameter estimation technique and a data fusion method, and analyzed the proposed method by simulation and the measurement of the real VL channel characteristics.

The Analysis of Effects of LED Panel Position and Lighting Angle on Communication Channel Quality in Indoor Visible Light Communication Systems (살내 가시광 무선 통신 시스템에서 LED 패널 위치 및 발광 각도가 통신 채널 품질에 미치는 영향 분석)

  • Do, Tronghop;Hwang, Jun-Ho;Yoo, Myung-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.9B
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    • pp.1108-1116
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    • 2011
  • The visible light communication system that transmits data by controlling light emission of LED and receives data through photo detecter is considered as one of the strong candidates of the next generation wireless communication systems. The visible light communication provides both lighting and wireless communication wherever the LED lamps are installed. Due to the feature of visible light communication system, the communication is possible within the area that LED light reaches, and the communication quality depends on the light intensity received at the receiver. In this paper, we analyze the effects of LED panel position and lighting angel on communication channel quality in visible light communication systems. Through computer simulations, we prove that position of LED panel and light angle have a great impact on illuminance and SNR of the visible light communication systems.

Performance analysis of the visible light communication in seawater channel (해수채널 환경에서 가시광 통신 성능 해석)

  • Sohn, Kyung-Rak
    • Journal of the Korean Society of Marine Engineering
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    • v.37 no.5
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    • pp.527-532
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    • 2013
  • The wireless visible light communication technology has received great attention for high-data rate services in the room and underwater. However, performance of a visible light seawater link is limited by multiple constraints from the current light source and detector technology, and underwater channel conditions. In this paper, performance of the line of sight underwater link was analyzed in terms of signal to noise ratio and bit error rate of the detector. Roles of different parameters such as data rate, transmission distance, and attenuation coefficient, are studied. Through the modeling and simulation of the OOK and L-PPM modulation technologies for undersea environment application, the advantages and limitations are described in detail.

Design and Performance Analysis of Visible -Light Wireless Communication System using LED

  • Choi, Jae Myoeng
    • Journal of Advanced Information Technology and Convergence
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    • v.8 no.2
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    • pp.147-157
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    • 2018
  • In this study, we analyzed an outdoor visible light communication system and implemented it through a simulation. We designed a Reed-Solomon encoder, a variable interleaver structure, and set it to the Institute of Electrical and Electronics Engineers (IEEE) 802.15.7 PHY I specification mode. We also analyzed the performance of an additive white gaussian noise (AWGN) channel environment using a root-raised-cosine (RRC) filter, implemented a MATLAB simulation and analyzed its performance. The results showed a requirement for an additional signal-to-noise ratio (SNR) of approximately 1.5 dB in a 3-ray multipath visible light channel environment than in an AWGN environment.

Design and Implementation of Visible Light Communication Circuit with a Built-in Distance Compensation Function (거리 보상 기능이 내장된 가시광 통신 회로 설계와 구현)

  • Park, Jeong-Uk;Lee, Yong Up
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.4
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    • pp.740-749
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    • 2015
  • In the visible light (VL) communication based on the conventional LED lights, depending on the increase of the communication range, the signal received at the photodiode of the VL receiver has usually the random distorted and decreased amplitude due to the path loss and fading effects of the VL channel. In order to overcome this problem, we propose, design, and implement the visible light communication circuit based on the comparator threshold voltage, where has a built-in distance compensation function. In addition, the performance of the proposed technique is evaluated and analyzed depending on the distance and communication speed through comparing the proposed VLC system based on the threshold voltage with the conventional one.

VLC Channel Model Considering Indirect Light (간접 조명 환경 실내 가시광 통신의 채널 모델)

  • Lee, Jung-Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.8
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    • pp.706-712
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    • 2013
  • In this paper, channel modeling of VLC(Visible Light Communication) was investigated under indirect lightning circumstance which was the way that all phontons started from LED(Light Emitting Diode) were reached on the floor with NLOS paths. I supposed width(6m), depth(4m), height(2.2m) cube room circumstance for VLC communication channel and supposed that 4 LEDs were located at 2m height, which emitted photons at the direction of wall and ceiling. Channel characteristics, which were power attenuation and delayed receiving of light signal, were abstracted from receivers(PDs) which were located at 0.5m above from floor. The availability of channel was verified via BPSK based communication simulation.

Efficient Data Transmission in LED-based Visible Light Communication Using Variable RGB Interleaving scheme (가변적인 RGB Interleaving을 활용한 LED 기반의 가시광 통신에서 효율적인 데이터 전송 기법)

  • Seo, Hyo-duck;Lee, Kyu-jin
    • Journal of Convergence for Information Technology
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    • v.7 no.6
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    • pp.167-172
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    • 2017
  • In this paper, we propose a variable RGB interleaving technique for efficient data transmission in LED based visible light communication system. Visible light communication systems that utilize light as a resource for data transmission are affected by the nature of light and the three primary colors of light. However, the nature of light, such as light reflection, diffraction, and superposition, causes interference of the data to be transmitted, causing burst errors in the data. Such a problem causes the BER performance of the visible light communication system to degrade. To solve these problems, this paper attempts to utilize the variable RGB interleaving technique. Through variable RGB interleaving, data burst errors can be reduced and inter channel interference in a visible light communication system can be reduced. In addition, if the proposed system is applied to meet the QoS that depends on the importance of data or the requirements of the user, it can provide QoS requested by the user and enable efficient data transmission.

Visible Light Communication Systems for Sensor Networks Using Synchronizing Pulse Transmission Through the Power Lines (전력선 전송 동기신호를 이용한 센서 네트워크용 가시광통신시스템)

  • Lee, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.22 no.3
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    • pp.212-218
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    • 2013
  • In this paper, we introduce a new method to reduce the inter-channel crosstalk in visible light communication (VLC) systems using the synchronizing pulses transmitted through the power lines. Synchronizing pulses are simultaneously transmitted to multiple VLC transmitters and receivers through the 220V power line. Each VLC transmitter modulates an LED and each VLC receiver demodulates the signal light in the time slot that is allocated with reference to the synchronizing pulses. This method is very simple and effective to prevent the inter-channel crosstalk in VLC systems for sensor networks because every VLC system can easily get the synchronizing pulses from the nearby power line.

Performance Analysis of the Visible Light Communication System based on MIMO under Various Interference environments (다양한 간섭환경에서 MIMO기반 VLC 시스템의 성능 분석)

  • Lee, Byung-Jin;Kim, Yong-Won;Kim, Kyung-Seok
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.13 no.3
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    • pp.1-7
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    • 2013
  • We perform simulation. It is that LED panels is fixed and moving the terminal with PD in order to analyze the performance of visible-light wireless communication system based on MIMO under variety of the interference environment. And, based on the technology MIMO, we analyzed whether the interference caused by external light to give what effect changes in the quality of the communication channel. The distortion due to time delay in channel transmission must be compensated by using the equalizer. Especially, use of equalizer is need absolutely as data rate becomes high speed. Therefore, in this paper, the system VLC, were analyzed BER performance using channel equalization.

Multi-coded Variable PPM for High Data Rate Visible Light Communications

  • Moon, Hyun-Dong;Jung, Sung-Yoon
    • Journal of the Optical Society of Korea
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    • v.16 no.2
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    • pp.107-114
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    • 2012
  • In this paper, we propose a new modulation scheme called multi-coded variable pulse position modulation (MC-VPPM) for visible light communication systems. Two groups of signals (Pulse Width Modulation (PWM) and Pulse Position Modulation (PPM) groups) are multi-coded by orthogonal codes for transmitting data simultaneously. Then, each multi-level value of the multi-coded signal is converted to pulse width and position which results in not only an improved data rate, but also a processing gain in reception. In addition, we introduce average duty ratio and cyclic shift concepts in PWM through which dimming control for light illumination can be supported without any degradation in communication performance. Through simulation, we confirm that the proposed MC-VPPM shows a comparable BER curve and much greater achievable data rate than the conventional VPPM scheme using a visible light optical channel environment.