• Information and Communications Magazine
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• v.28 no.12
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• pp.61-68
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• 2011

가시광 무선 통신 기술은 LED의 반도체 특성을 이용하여 디지털 신호를 송신하고, 빛의 유무를 판단할 수 있는 PD를 이용하여 광전 변환을 통해 디지털 데이터를 수신할 수 있는 차세대 무선 통신 기술로 평가받고 있으며, 이에 대한 많은 연구가 진행되고 있다. 본고에서는 특히 가시광 무선 통신 기술을 활용할 수 있는 응용서비스 분야를 설명하고, 특히 실내/실외 위치 측정 기술의 국내외 연구 동향에 대해 소개한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1595-1600
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• 2011

We analyzed the noise effect from artificial light and sunlight on the signal performance in visible light communication systems based on Intensity Modulation/Direct Detection(IM/DD). System performance was experimentally demonstrated by transmitting 50ksysmbol/s QPSK signals at 2MHz sub-carrier. And received signals were analyzed using EVM and RF spectrum. Finally, the system performance was improved by utilizing a visor and we confirm that the outdoor visible light communication was possible using IM/DD method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.668-670
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• 2018

Recently, VLC(Visible Light Communication), which is a technology to communicate wirelessly by carrying information in lights based on LED, is getting attention. If we use the VCL, we don't need to receive authorization because it uses the existing industrial infrastructure(LED infrastructure) and frequency band together and there is the little possibility of interference and it has a high level of security by removing visible light in a portion where data transfer is not required. These are the advantage of VCL. In this paper, we study the traffic and signal system based on Visible Light Communication with consideration for these advantages.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.35-43
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• 2017

In this paper, we propose indoor IoT monitoring system based on visible light communication using smart phone with attracting attentions in recent wireless communication. The main features and contributions of the proposed system developed in this paper are as follows. First, the actual data generated within indoor can be processed via the server by using only the visible light communication. Second, the collected data by using the visible light communication can be monitered by smart phone. Performance evaluation of the proposed system is performed under illumination of the normal fluorescent lamps. We first check successful transmission between transmitting module and receiving module of the data collection system. The monitoring system is tested according to the change of the degree of condensing and distance of the LED and the decoding success rate of the proposed smart phone application. We expect that the proposed system can be applied for indoor and outdoor IoT areas together.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.588-594
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• 2015

Although GPS technology for location positioning system has been widely used, it is difficult to be used in intelligent transport systems, due to the large positioning error and limited area for receiving radio signals. Thanks to the rapid development of LED technology, LED lights become popular in many applications. Especially, visible light communications (VLC) has raised a lot of interests because of the simultaneous functioning of LED illumination and communication. Recent studies on positioning system using VLC mainly focused on indoor environments and still difficult to satisfy positioning accuracy and simple implementation simultaneously. In this paper, we propose a positioning system based on VLC using the coordinate information of LEDs installed on the road infrastructure. Extracting the LED signal, obtained through VLC, from the easily accessible camera image, it is possible to estimate the position of the car on the road. Simulation results show that the proposed scheme can achieve a high positioning accuracy of 1 m when large number of pixels is utilized and the distance from the LED light is close.