• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.409-412
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• 2004

무선통신은 현재 우리 삶의 일부분을 차지하고 있으며, 유선 통신의 한계인 공간적 제약성을 극복함으로서 일상 또는 산업현장에서 없어서는 안되는 아주 중요한 부분이 되어 있다. 현재 산업현장에서 사용되고 있는 유선과 무선콘트롤러의 성능을 향상시키기 위해 컨볼루션 부호와 CRC부호를 적용한 무선 콘트롤러를 구현하였다. 400Mhz대역의 RF모듈을 사용하여 송수신 프로그램에 컨볼루션 부호를 적용하였을때와 적용하지 않았을때의 각각의 수신율을 테tm트 비교해 보았다. 컨볼루션 부호는 POLYNOMIAL함수를 g1(X) =1 + X + X$^2$, g2(X) =1 + X$^2$로 사용하였고 구속장 K=3, 부호율 1/2인 부호를 사용하였다. CRC부호는 POLYNOMIAI. 함수를 X$^{15}$ + X$^2$+ 1 로 사용하여 총 CRC비트는 16bit가 되게 하였다.

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.39-42
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• 2002

RS-232C는 정보기기들을 연결하는 직렬통신 표준으로, 간단한 구조로 인해, 복잡한 요구 조건이 없는 상용 기기들의 제어 및 감시용으로 사용되고 있다. 최근 무선동신기술이 발전함에 따라, 저가격의 무선통신 기술을 활용하여 무선 RS-232C에 대한 요구가 늘어나고 있다. 무선 RS-232C로 기존 유선의 RS-232C를 대체함으로서, 기존 시스템의 변경없이 편리한 접속기능을 대체한 수 있을 것이다. 본 논문에서는 유선 RS-232C를 대체하는 무선 RS-232C 모듈을 채용하여, 전력제어에 사용하는 배전자동화 장치의 관리를 간편하게 하는 시스템의 구현에 대해서 다루고 있다. 배전 자동화시스템은 일종의 SCADA시스템의 일부로서, 통신 프로토콜로서 산업용 DNP3.0을 사용하고 있다. 무선 RS-232C 링크의 신뢰성을 확보하기 위하여, 무선 구간에 DNP3.0을 채택하였으며, 무선 통신방식으로는 무선 RF, 블루투스(Bluetooth), 무선랜(wireless LAN)등 3가지 방식을 채용하여, 설계, 구현내용을 기술하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.1-6
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• 2008

A dual band I/Q modulator which converts baseband input signals to 2.4GHz or 5GHz RF output has been proposed. The dual band I/Q modulator for 2.4GHz and 5GHz wireless LAN applications consists of $90^{\circ}$ phase shifter and wideband mixer. The I/Q modulator showed 15dB conversion loss at 2.4GHz and 16dB conversion loss at 5GHz. The sideband suppression is about 15dBc at 2.4GHz and 16dBc at 5GHz. Measured data shows 8.5% EVM at 2.4GHz, and 10% EVM at 5GHz for QPSK with symbol rate of 11Mbps. A carrier rejection is about 40dBc at 2.4GHz/5GHz band, and the I/Q modulator satisfied the output wireless LAN spectrum mask with baseband input signal.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.787-792
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• 2004

This paper shows the design, fabrication and performance of oscillator appled to 5.5GHz RF module for local wireless communication system. Super low noise HJ FET of NE3210S01 is used to obtain a good phase noise Performance. The design Parameters for the optimum operating performance are simulated with ADS simulation. The measured out Power is 10 dBm at 5.5GHz, the second harmonic suppression -31 dBc, and the phase noise characteristics -98.83 dBc at 100kHz offset frequency, respectively. This implemented oscillator is available to local wireless Communication system.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.339-342
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• 2003

This paper describes an RF/IF module for 2.4GHz wireless video and audio receivers The designed circuits are implemented using a Teflon board of which the size is $53mm\times42mm$. The measured LNA gain is 15dB, and the VCO output levels are around 2dBm. The sensitivity of the receiver is about -80dBm. The manufactured module consumes 140nA from a 8V supply.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.1
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• pp.60-65
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• 2006

Recently, various ubiquitous networking services are developed and implemented for easy living. In general, new ubiquitous networking services require the new infrastructure including equipments and devices. However, it is difficult to replace existing infrastructure and devices with new ones in the home or office because of cost and maintenance problems. In this paper, we developed small-size web based RF wireless communication systems for sensor network applications. The designed RF systems are implemented using commercial system on a chip (SoC) on existing infrastructure and devices. The developed systems are tested for light control and temperature sensing and they are applied to sensor network training courses for students and engineer as well as various practical applications.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.39-48
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• 2009

The Spectrum Sensing technology is the core technology of the Cognitive Radio (CR) system that is one of the future wireless communication technologies. This is the technology that temporarily allocates the frequency bandwidth by scanning surrounding wireless environments to keep licensed terminals and search the unused frequency bandwidth. In this paper, we implement the efficient Spectrum Sensing methods based on CR technology in an embedded board. The DVB-H signal with the 6MHz bandwidth is used as the RF input signal. And we confirm the Spectrum Sensing result using Modified Periodogram Method, Welch's Method, SCF Method. And also, We examine the execution speed of each of detailed functions and the performance of Spectrum Sensing methods on TI320C6416 DSP board inserted in an embedded board.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1689-1695
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• 2008

The development of low-power wireless communication and low-cost multi-functional smart sensor has enabled the sensor network that can perceive the status information in remote distance. Sensor nodes are sending the collected data to the node in the base station through temporary communication path using the low-cost RF communication module. Sensor nodes get the energy supply from small batteries, however, they are installed in the locations that are not easy to replace batteries, in general, so it is necessary to minimize the average power consumption of the sensor nodes. It is known that the RF modules used for wireless communication are consuming 20-60% of the total power for sensor nodes. This study suggests the probability inference heuristic based non-periodic transmission to send the collected information to the base station node, when the calculated value by probability is bigger than an optional random value, adapting real-time to the variation characteristics of sensing datain order to improve the energy consumption used in the transmission of sensed data. In this transmission method suggested, transmitting is decided after evaluation of the data sensed by the probability inference heuristic algorithm and the directly sensed data, and the coefficient that is needed for its algorithm is decided through the reappearance rate of the algorithm verification data.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.49-54
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• 2009

This paper proposes a new approach to provide RF communication channel and electric power transmission to overcome the weakness of conventional tests, which may cause several problems. When an RF communication device is used to communicate between launch vehicle and launch complex in stead of using harness umbilical, it may draw the simplicity of ground test equipments, cost-saving, and the reduction of test time. In addition, if an RF power transmission device is adopted to supply on-board power of launch vehicle, it can replace expensive on-board batteries, which may be degraded easily by the repeated charging and discharging processes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.631-634
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• 2009

Recent advances in wireless communication, electronics, MEMS device, sensor and battery technology have made it possible to manufacture low-cost, low-power, multi-function tiny sensor nodes. A large number of tiny sensor nodes form sensor network through wireless communication. Sensor networks represent a significant improvement over traditional sensors, research on Zigbee wireless image transmission has been a topic in industrial and scientific fields. In this paper, we design a Zigbee wireless image sensor node and multimedia monitoring server system. It consists of embedded processor, memory, CMOS image sensor, image acquisition and processing unit, Zigbee RF module, power supply unit and remote monitoring server system. In the future, we will further improve our Zigbee wireless image sensor node and monitoring server system. Besides, energy-efficient Zigbee wireless image transmission protocol and interworking with mobile network will be our work focus.