• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1117-1125
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• 2011

In this paper, as a study of the simple visible light communication(VLC) with LED light, the visible light communication system that are made up with the $3{\times}3$ white LED array for visible light transmission, various photodiodes for visible light reception, and a non-carrier NRZ-OOK modulation scheme is designed and implemented to have a 115.2 kbps data speed at 2.5 m distance between transmitter and receiver. For the performance analysis of the developed VLC system, the maximum distance between VLC transmitter and receiver on the conditions of various transmission speeds, the number of LED array, or the various kind of LED and photodiode is obtained, and various performances are analyzed by experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.1
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• pp.76-79
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• 2015

Visible light communication (VLC) is a short range optical communication technology using light emitting diodes. In this paper, we implement variable pulse position modulation (VPPM) defined in the IEEE 802.15.7 standard with a Cortex-M processor, which is a new modulation scheme for VLC providing a dimming control mechanism for flicker-free optical communication. The synchronization procedure between the transmitter and receiver is not defined clearly in the VPPM standard. In order to synchronize the transmitter and receiver easily, two overhead bits are used including one start bit and one stop bit modulated by on-off keying (OOK). Experimental results under various environmental conditions show that the proposed VPPM can support a seamless 100 Kbps data rate with 10 levels in the dimming control.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.147-150
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• 2007

This paper presents an advanced RFID reader system implementing multi-protocols and multi-standards at 900MHz. In accordance with the strict regulations specified by ISO 18000-6 B-Type and EPC Global Gen 2, we have designed corresponding systemic factors which meet the domestic radio frequency utilizing bands of 910-914MHz. In addition, we develop numerous crucial factors of system compatibility options including SSB (Single-Side Band) and DSB (Double-Side Band) specifications, also OOK (On-Off Keying), ASK (Amplitude Shift Keying) and PR-ASK (Phase Reversed-Amplitude Shift Keying) modulation formula. Remarkable technical features of system in this paper can be the direct conversion routines using I/Q Modulation/Demodulation respectively, and Full-Duplex formulation operating at identical frequency bands.

• The Journal of the Acoustical Society of Korea
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• v.27 no.7
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• pp.342-349
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• 2008

Multipath makes clear message transfer difficult in the underwater communication. To solve this problem, we propose a new method producing proper MFSP (Modulation Frequency Shift Period) which could be obtained by calculating time delay caused by different path from a transmitter to a receiver. At the transmitter end, messages were divided according to the size of the MFSP and transmitted accordingly alternating Frequency. At the receiver end, the received messages were demodulated in order to recover the original message by the adaptive BISMO algorithm which is constructed at the algorithm design stage. Adaptive MFSP and estimated BER (Bit Error Rate) were calculated through simulation test.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.98-104
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• 2013

This paper presents a WBAN UWB receiver circuit for RTLS(real time location system) and wireless data communication. The UWB receiver is designed to OOK modulation for energy detection. The UWB receiver is designed for sub-sampling techniques using 4bit ADC and DLL.The proposed UWB receiver is designed in $0.18{\mu}m$ CMOS and consumes 61mA with a 1.8V supply voltage. The UWB receiver achieves a sensitivity of -85.7 dBm, a RF front-end gain of 42.1 dB, a noise figure of 3.88 dB and maximum sensing range of 4 meter.

• Journal of Satellite, Information and Communications
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• v.11 no.2
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• pp.65-68
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• 2016

In this paper, visible light wireless communication system according to the climate is studied in the marine environment. The light visibility can be determined by the different weather conditions (clear air, rain, storm, fog) in Kim's atmospheric channel model. By simulating the OOK-NRZ modulation technique, the BER performances are compared in the different weather conditions. In the field test, the error bit is measured in the visible-light communication. The effectiveness of visible light communication in the marine environment is confirmed by comparing the analysis of simulations and field experiments.

• Journal of Advanced Marine Engineering and Technology
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.3
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• pp.123-129
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• 1985

This paper describes the determination of threshold value in order to determine the presence of absence of weak signal with SNR of 0 dB in 100kHz bandwidth. As a detection method, it has been used a recent LOC structure fitting for detecting weak signal in stead of a conventional method like Neyman-Peason crtical criterion. The signal for detection is the OOK modulation signal used in data and morse code transmission. The non-Gaussian noise similar to Laplacian type has been chosen in transmission path. As a result of experiment, comparing probability of detection by one critical point with that by two critical points with fixing as arbitrary false alarm probability, we have found that method has been shown to be better than the conventional method.

• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.12-16
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• 2013

In this paper, we proceeded a study about the mobile software applications using smartphone technology. Firstly, we proposed a communication which a position data transmission technique using LED flashlight with built-in smartphone and we develop the application to perform a remote controller for beam-forming communication based on visible light associated with the position of Smartphone user. OOK modulation was applied for transmitting location data via LED backlight flash of smartphone and PD is used for detecting receiving light. In case of remote controller application which was controlled by WiFi IP-networking and it controls LED direction for beam-forming communication. These suggestion can be a good example for ubiquitous position recognition system using smart phone and software.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.9-15
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• 2006

In this paper, signal processing techniques for noncoherent impulse-radio-based UWB (IR-UWB) communication system are proposed to provide system implementation of low power consumption and low complexity. The proposed system adopts a simple modulation technique of OOK (on-oft-keying) and noncoherent signal detection based on signal amplitude. In particular, a technique of a novel high speed digital sampler using a stable, lower reference clock is developed to detect nano-second pulses and recover digital signals from the pulses. Also, a 32 bits Turyn code for data frame synchronization and a convolution code as FEC are applied, respectively. To verify the proposed signal processing techniques for low power, low complexity noncoherent IR-UWB system, the proposed signal processing technique is implemented in FPGA and then a short-range communication system for wireless transmission of high quality MP3 data is designed and tested.