• Journal of Biosystems Engineering
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• 제17권1호
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• pp.45-54
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• 1992

A wireless control system was designed and constructed to control the rice transplanter of walking type with remote control. VHF(very high freqency) was sent from wireless transmitter to wireless reciever by usig 6 channels to control main clutch, steering clutch, plant lever and throttle lever within 200 meter distance between remote control and rice transplanter. The rice transplanter with wireless control system showed good performance for accuracy of travel speed, traveling mobility and turning diameter in the concrete, paddy and dry field. It is concluded that the developed wireless control system could be adapted to control not only conventional rice transplanters but also most of the agricultural machine by changing some parts of the control system.

• ETRI Journal
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• 제35권4호
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• pp.578-586
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• 2013

Using a sub-terahertz (sub-THz) wave generated using a photonics-based technology, a high-speed wireless link operating at up to 10 Gbps is designed and demonstrated for realization of seamless connectivity between wireless and wired networks. The sub-THz region is focused upon because of the possibility to obtain sufficient bandwidth without interference with the allocated RF bands. To verify the high-speed wireless link, such dynamic characteristics as the eye diagrams and bit error rate (BER) are measured at up to 10 Gbps for non-return-to-zero pseudorandom binary sequence $2^{31}-1$ data. From the measurement results, a receiver sensitivity of -23.5 dBm at $BER=10^{-12}$ is observed without any error corrections when the link distance between the transmitter and receiver is 3 m. Consequently, we hope that our design and experiment results will be helpful in implementing a high-speed wireless link using a sub-THz wave.

• JSTS:Journal of Semiconductor Technology and Science
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• 제4권3호
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• pp.182-188
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• 2004

We demonstrate a $2.1\;{\times}\;1.0\;{\times}\;0.1cm^3$ sized compact transmitter using LTCC System-in-Package (SiP) technology for 60GHz-band wireless communication applications. For low-attenuation characteristics and resonance suppression of the SiP, we have proposed and demonstrated a coplanar double wire-bond transition and novel CPW-to-stripline transition integrating air-cavities as well as novel air-cavities embedded CPW line. The fabricated transmitter achieves an output of 13dBm at a RF frequency of 62GHz, an IF frequency of 2.4GHz, and a LO frequency of 59.6GHz. The up-conversion gain is 11dB, while the LO signal is suppressed with the image rejection mixer below -21.4dBc, and the image and spurious signals are also suppressed below -31dBc.

• Journal of Communications and Networks
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• 제12권4호
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• pp.308-316
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• 2010

The problem of compressed sensing (CS) based multiple access is studied under the assumption of random data traffic. In many multiple access systems, i.e., wireless sensor networks (WSNs), data arrival is random due to the bursty data traffic for every transmitter. Following the recently developed CS methodology, the technique of compressing the transmitter identities into data transmissions is proposed, such that it is unnecessary for a transmitter to inform the base station its identity and its request to transmit. The proposed compressed multiple access scheme identifies transmitters and recovers data symbols jointly. Numerical simulations demonstrate that, compared with traditional multiple access approaches like carrier sense multiple access (CSMA), the proposed CS based scheme achieves better expectation and variance of packet delays when the traffic load is not too small.

• Journal of Biosystems Engineering
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• 제24권1호
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• pp.75-80
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• 1999

Signal separation and transmission are essential for automatic breeding management of domestic animals. Electronic identification system could transmit the signal of an individual within a defined range to a personal computer by an electromagnetic signal recognition method. Signals for individual recognition were originated by controlling 12 tri-state pins of IC(PT2262) in a transmitter. PT 2262 can generate 4,096 codes. These encoded signals were modulated and transmitted with wireless lines from the transmitter. Then they were demodulated in a receiver, and the signals were transmitted to the micro-processor through an interface and were identified in a PC.

• 전자통신동향분석
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• 제33권2호
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• pp.39-47
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• 2018

The fundamental problem of communication is that of transmitting a message from a source to a destination over a channel through the use of a transmitter and receiver. To derive a theoretically optimal solution, the transmitter and receiver can be divided into several processing blocks, with each component analyzed and optimized. The idea of machine learning (or deep learning) communications systems goes back to the original definition of the communi-cation problem, and optimizes the transmitter and receiver jointly. Although today's systems have been optimized over the last decades, and it seems difficult to compete with their performance, deep learning based communication is attractive owing to its simplicity and the fact that it can learn to communicate over any type of channel without the need for mathematical modeling or analysis.

• 조명전기설비학회논문지
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• 제22권6호
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• pp.116-126
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• 2008

본 논문에서는 2.4[GHz]와 5[GHz]로 동작하는 Dual-band WLAN 송신기의 설계에 대하여 기술한다. Dual-band WLAN 송신기는 2.4[GHz] 대역과 5[GHz] 대역에서 각각 동작할 수 있도록 설계되었다. 이중대역의 구조를 갖는 송신 부는 2.4[GHz] 과 5[GHz] 주파수에서 동작하는 증폭기와 두 개의 VCO(Voltage Controlled Oscillator)또는 주파수 가변 범위가 매우 넓은 VCO를 사용해야 한다. 이 문제는 크기와 소비전력으로 나타나며, 이를 해결하기 위하여 이중대역 송신 모듈을 제안하였다. 이 송신부는 단일 송신 블럭을 사용하여 입력되는 주파수와 인가하는 바이어스 전압에 따라, IEEE 802.11b/g의 2.4[GHz] 대역신호에 대해서는 증폭기로 동작하고 IEEE로 802.11a의 5.8[GHz] 대역신호는 주파수 체배 방식을 이용하여 출력신호를 얻도록 설계하였다. 출력스펙트럼은 중심주파수에서 각각 +11[GHz], +20[MHz], +30[MHz] offset인 주파수에서 적응형 방식이 아닌 경우와 비교하여 4[dB], 6[dB], 16[dB]의 ACPR특성이 향상되었으며, IEEE 802.11a 무선 랜 송신스펙트럼 마스크 규격을 만족하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.121-124
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• 2001

In this paper, we propose a robust trellis coded OFDM(orthogonal frequency division multiplexing) system for wireless communications over frequency selective fading channels. Computer simulations show that the proposed system achieves the better frame error rate(FER) performance as compared with the conventional Space time coded OFDM system in the correlated channel with multiple transmitter antennas.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.259-262
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• 2003

In this paper, we designed and implemented digital wireless audio system with embedded RTOS using Bluetooth. Transmitter is consisted of a Settopbox, FIFO for interface block, Microprocessor(ARM7TDMI), UART driver and Bluetooth module. Receiver is consisted of a Microprocessor, AC-3 decoder, Bluetooth module and a Speaker with Amp. We programed Bluetooth protocal stack of HCI, L2CAP, and RFCOMM, so that Bluetooth module interacts with CPU.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1889-1910
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• 2017

This paper investigates a protocol so-called Adaptive Harvest Then Transmit (AHTT) for wireless powered communication networks (WPCNs) in multiple-input single-output (MISO) downlink systems, which assists in transmitting signals from a multi-antenna transmitter to a single-antenna receiver. Particularly, the power constrained relay is supplied with power by utilizing radio frequency (RF) signals from the source. In order to take advantage of multiple antennas, two different linear processing schemes, including Maximum Ratio Combining (MRC) and Selection Combination (SC) are studied. The system outage capacity and ergodic capacity are evaluated for performance analysis. Furthermore, the optimal power allocation is also considered. Our numerical and simulation results prove that the implementation of multiple antennas helps boost the energy harvesting capability. Therefore, this paper puts forward a new way to the energy efficiency (EE) enhancement, which contributes to better system performance.