• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.291-291
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• 2006

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.179-179
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.186-187
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• 2002

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.283-291
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• 2012

In this paper, a compact antenna is designed for the UWB lower half-band WVAN Gbps data-rate transceiver. The proposed antenna broadens the bandwidth less than -10 dB by placing the ring stubs and an open stub on the rectangular monopole above the partial ground and creating multiple resonant current paths. The designed antenna goes through the electromagnetic simulation and is fabricated and the implemented antenna has the characteristics of the return loss lower than -10 dB, the antenna gain greater than 5 dBi, and the efficiency over 80 % in the UWB lower half-band ranging from 3.197 GHz to 4.732 GHz. Therefore, it is thought that the proposed antenna is suitable for the size-reduced and excellently performing wireless communication transceiver.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.71-78
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• 2009

An 8${\times}$8-Gb/s/channel 4-PAM transceiver was designed for high speed memory applications by using 70nm DRAM process with 1.35V supply. An asymmetric 4-PAM signaling scheme is proposed to increase the voltage and time margin of upper and lower eyes in 3-class eye opening. A mathematical basis shows that this scheme statistically reduces 33% of reference noise effect in a receiver. Also, an adaptive pre-emphasis scheme, which utilizes a lone-bit pulse with integrator at the receiver, is introduced to reduce ISI for a simple DRAM channel. In this scheme, an integrating clock timing calibration by using a pre-determined pattern is proposed for the optimum ISI measurement.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.499-506
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• 2015

Global navigation satellite systems (GNSS) is operating widely in civil and military area. GNSS signals, however, can be easily interfered because its signal is vulnerable to jamming. Thus, a sort of backup or alternative system is needed in order that the navigation performance is assured to a certain degree in case of GNSS jamming. In order to suggest a series of backup or alternative system of regional navigation, in this paper, we introduced a high altitude long endurance unmanned aerial vehicle (HALE UAV) with pseudolites using inverted GPS and transceiver system. We simulated the positioning error of the regional navigation system using HALE UAV with inverted GPS or transceivers concepts. We estimated the position error of HALE UAV calculate user position errors based on the position error of HALE UAV and general pseudorange error.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.347-354
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• 1999

Generally, transceiver is operated to the remote control for the purpose of breading the traffic zone which is established on a mountain peak, island and building top using private line. Therefor, the remote control system of public radio station have been the very important role that is decision the quality relate to the quickness, accuracy, safety of communication on old type transceiver of SSB, VHF etc. In the case of using the only 1 private line which is exchanged voice signal with data signal had mixed or interrupted for up/down of channel, PTT control and monitoring of transmission channel and power. The up/down of channel and PTT control is according to the ASK and the data of monitoring is transfered to the FSK modulation, additional algorithm is studied on the serial protocol and traffic sequence using the MCS-51 processor in the simplex communication methode.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1654-1660
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• 2004

In this paper, we describes the design and implementation of LonWorks communication module for distributed intelligent control using LonWorks technology of Echelon. LonWorks communication module can be divided hardware and firmware. First, hardwares is divided into microcontroller attaching sensors and LonWorks components for working together control network and data network. Hardwares are consisted of neuron chip, microcontroller, transceiver, LONCard. Second, operating firmware is realized with neuron C using NodeBulider 3.0 development tool. Produced and implemented LonWorks communication module is pretested using LTM-10A, Gizmo 4 I/O board, parallel I/O Interface. For field test, microcontroller module part is tested by HyperTerminal, communication procedure in data network is certified by transmitting and receiving short message using LonMaker for Windows tool. Herewith, LON technology is based on network communication technique using LonWorks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.406-409
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• 2003

In this paper, a 4-wavelength optical transceiver system is designed and implemented by using TFF (thin film filter) type OADMs (optical add-drop multiplexers). In this new system, the wavelengths of 1510 nm and 1530 nm are used for uploa and download signals, respectively, as well as the wavelengths of 1550 nm and 1310 nm which have been utilized in a 2-wavelength optical transceiver systems. The 4-wavelength optical module show pass characteristics of -1.6 dBm, -1.7 dBm, -5.6 dBm, -5.8dBm for 1510nm, 1530 nm, 1550 nm, 1570 nm, respectively, with 1.2 dBm of input laser power. The isolation for characteristics of the optical module for all the wavelengths are less than -40dB, which is very acceptable for filed requirements.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.280-285
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• 2015

We consider a linear transceiver design method for multi-user multiple-input multiple-output (MIMO) downlink channels where a base station (BS) equipped with a finitely large number of antennas. Although a matched-filter precoder is a capacity-achieving method in massive MIMO downlink systems, it cannot guarantee to achieve the multi-user MIMO capacity in a finitely large number of antennas due to inter-user interferences. In this paper, we propose a two-stage precoder design method that maximizes the sum-rate of cell-edge users when the BS equipped with a finitely large number of antennas. At the first stage, a matched-filter precoder is adopted to exploit both beamforming gain and the reduction of the dimension of effective channels. Then, we derive the second stage precoder that maximizes the sum-rate by minimizing the weighted mean square error (WMSE). From simulation and analysis, we verify the effectiveness of the proposed method.