• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.440-446
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• 2010

Convergence of IT and BT is considered in many area, especially in medical care industry. The example of this trend is a capsule endoscope. But in a capsule endoscope, communication through human body has a few restrictions. At first, the transmit power should be limited not to have a bad effect on human organs and for the battery capacity. Second, the channel characteristic of human body has not been examined exactly. Third, general modulation / demodulation techniques which require a channel estimation cannot be used because of battery limit. There also may be a lot of interference signals because a capsule endoscope uses UWB bandwidth. In this paper, we introduce Chirp Spread Spectrum Differential Binary Phase Shift Keying(CSS-DBPSK) and propose Chirp Spread Spectrum On-Off Keying(CSS-OOK) which don't require a channel estimation and robust to interference signals. Using CSS-DBPSK or CSS-OOK, we can get 5 dB or 2~3 dB of Eb/N0 gain at 10-5 target BER. And if there are interference signals, those gains of CSS-DBPSK and CSS-OOK are increased.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.1
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• pp.35-42
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• 2022

Visible light communication (VLC) is a method of transmitting data through LED blinking and is vulnerable to eavesdropping because the illumination affects the wide range of area. IEEE standard 802.15.7 defines On-Off Keying (OOK), Variable Pulse Position Modulation (VPPM), and Color Shift Keying (CSK) as modulation. In this paper, we propose an encryption method in VPPM for secure communication. The VPPM uses an encoding method called 4B6B where 16 different outputs are represented with 6-bit. This paper extends the number of outputs to 20, to add complexity while not violating the 4B6B generation conditions. Then each entry in the extended 4B6B table is scrambled using vigenère cipher. The probability of decrypting each 6-bit data is $\frac{1}{20}$. Eavesdropper should perform $\sum\limits_{k=1}^{n}20^k$ number of different trials to decrypt the message if the number of keys is n. The proposed method can be applied to OOK of PHY II and CSK of PHY III. We further discuss the secure encoding that can be used in OOK and CSK without performance degradation.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.119-120
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• 2008

본 논문에서는 ECMA 표준에 기반한 multi-gigabit packet 수신기를 위한 프레임 검출 방안을 제안한다. ECMA 표준은 60 GHz 대역에서 multi-gigabit 전송률을 달성하기 위하여 버스트 (burst) 송수신 방식을 사용하며 프리앰볼 (preamble)과 데이터 (data)로 이루어진 프레임 (frame)을 통하여 데이터 송수신이 이루어진다. 본 논문에서는 ECMA 표준 중 DBPSK (Differential Binary Phase Shift Keying)와 DQPSK (Differential Quadrature Phase Shift Keying) 그리고 OOK (On-Off Keying) 변조 방식을 지원하는 multi-gigabit 송수신 시스템을 위한 프레임 검출기를 설계하였다. 설계된 프레임 검출기는 동일한 구조 및 동작 방식을 통하여 고려한 모든 변조 방식들을 지원할 수 있을 뿐만 아니라 하드웨어 구현 복잡도가 낮은 장점을 지닌다.

• Current Optics and Photonics
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• v.6 no.1
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• pp.39-43
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• 2022

Underwater optical wireless communication (UOWC) is a good candidate for high-speed underwater wireless communication. In this work, we compare the performance of several modulation techniques for a UOWC system consisting of a light-emitting diode (LED) with an operating wavelength of 405 nm and a Si avalanche photodiode (APD). In this work, we consider six modulation schemes: 4-quadrature amplitude modulation (QAM), 8-QAM, quadrature phase shift keying (QPSK), binary phase shift keying (BPSK), on-off keying (OOK), and 4-pulse amplitude modulation (PAM). We also consider the cases of pure water and seawater for the working conditions. Our results show that 4-QAM and 8-QAM perform the best, in terms of communication distance and transmission power efficiency, for all water types considered.

• 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.

• Journal of IKEEE
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• v.23 no.2
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• pp.735-738
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• 2019

Recently, orthogonal non-orthogonal multiple access (O NOMA) with polar on-off keying (POOK) has been proposed to mitigate the severe effect of the superposition. However, it is observed that the performance of the O NOMA strong channel user is better than that of the perfect successive interference cancellation (SIC), i.e., the performance of a single user transmission with binary phase shift keying (BPSK). Can the performance of the BPSK modulation be better that that of itself? It is not normal. It should be clearly understood theoretically, with the ultimate bound, i.e., the channel capacity. This paper proves that the channel capacity of the O NOMA strong channel user is non-zero with zero power allocation. Thus, it is shown that the interference is transformed effectively into the meaningful signal.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.179-184
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• 2012

A conventional wireless rf communication has relatively high ratio of power dissipation to transmit power for short-range links, susceptibility to interference, interception and jamming of electromagnetic wave. The study on alternative using ultraviolet signal to remedy the shortcomings of conventional rf communication has recently received attention. In this paper, the simulation results about the data rate performance of ultraviolet non-line-of-sight communication are provided. It is found that the direction of transmitting beam, receiving field of view width and the transmitting signal power have a seriously effect on the data rate of on-off-keying non-line-of-sight ultraviolet communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1086-1103
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• 2004

Most research efforts on the OCDMA technology assume single-bit-per-symbol transmission techniques such as on-off keying. However, achieving high spectral efficiency with such transmission techniques is likely to be a challenging task due to the "unipolar" nature of optical signals. In this paper, an M-ary transmission technique using more than two equally-weighted codes is proposed for OCDMA local area networks, and ie BER performance and spectral efficiency are analyzed. Poison frame arrival and randomly generated codes are assumed for the BER analysis, and the probability of incorrect symbol detection is analytically derived. From the approximation, it is found that there exists an optimal code weight that minimizes the BER, and its physical interpretation is drawn in an intuitive and simple statement. Under the assumption of this optimized code weight and sufficiently large code dimension, it is also shown that the spectral efficiency of OCDMA networks can be significantly improved by increasing the number (M) of symbols used. Since the cost of OCDMA transceivers is expected to increase with the code dimension, we finally provide a guideline to determine the optimal number of symbols for a given code dimension and traffic load.

• Proceedings of the IEEK Conference
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• summer
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• pp.77-81
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• 2004

In this paper, we propose a analog front-end (AFE) for noncoherent On-Off Keying (OOK) Ultra Wide Band (UWB) system based on power detection. The proposed AFE are designed using 0.18 micron CMOS technology and verified by simulation using SPICE. The proposed AFE consist of Sample-and-Hold block, Analog-to-Digital converter, synchronizer, delayed clock generator and impulse generator. The time resolution of 1ns is obtained with 100MHz system clocks and the synchronized 10-bit digital outputs are delivered to the baseband. The impulse generator produces 1ns width pulse using digital CMOS gates. The simulation results show the feasibility of the proposed UWB AFE systems.

• 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.