• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.1-8
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• 2011

In this paper, a microstrip bandpass filter(BPF) with 3 dB bandwidth of more than 50 % at center frequency of 30 GHz was implemented. The implemented BPF is to be used as ASK(Amplitude Shift Keying) transmission and reception filters in IF band for THz transmitter and receiver capable of 10 Gb/s wireless data transmission. The microstrip BPF with ultra-wideband characteristics was implemented using a stepped-impedance lowpass filter(LPF) and a composite quarter-wave short stubs where the LPF is functioning as attenuating the upper stopband and quarter-wave short stubs is functioning as attenuating the lower stopband. The measured results are as follows; the insertion loss is 0.65 dB at 30 GHz, the stopband characteristics are -10 dB and -16 dB at 10 GHz and 50 GHz, respectively, and the passband flatness is ${\pm}0.5$ dB at 20~40 GHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.311-318
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• 2008

We propose new pulse shapes for FCC-compliant ultra-wideband (UWB) radios. The projections onto convex sets (POCS) technique is used to optimize temporal and spectral shapes of UWB pulses under the constraints of all of the desired UWB signal properties: efficient spectral utilization under the FCC spectral mask, time-limitedness, and good autocorrelation. Simulation results show that for all values of the pulse duration, the new pulse shapes not only meet the FCC spectral mask most efficiently, but also have nearly the same autocorrelation functions. It is also observed that our truncated (i.e., strictly time-limited) pulse shapes outperform the truncated Gaussian monocycle in the BER performance of binary TH-PPM systems for the same pulse durations. The POCS technique provides an effective method for designing UWB pulse shapes in terms of its inherent design flexibility and joint optimization capability.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2067-2068
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• 2006

초광대역 (UWB)통신기술을 응용한 다양한 무선측위시스템은 향후, 전기-IT융합 유비쿼터스 전기설비 환경의 센서네트워크에서 중요한 역할로 대두된다. 이러한 UWB기반의 무선측위시스템은 UWB송수신기 자체의 정밀거리산출기능의 정확도 정도에 따라 그 성능이 직접적으로 좌우된다. 본 논문에서는 현재 논의되고 있는 UWB 레인징기술에 대한 소개와 특히 저비용, 저전력 운영이 가능한 단순한 구조를 갖는 비가역성(Non-coherent) UWB 레인징 시스템구조에 대해 새롭게 제안하고자 한다.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.30-34
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• 2008

In this paper, we analyze the performance of pulse position modulation-time hopping ultra wide band (PPM-TH UWB) systems with antenna diversity technique in indoor wireless channel. A modified Saleh and Valenzuela (SV) model is adopted as a UWB indoor channel model. Perfect synchronization between a transmitter and a receiver is assumed. Therefore, coherent equal gain combining (EGC) scheme to collect the energy available in the multipath components is investigated. It is shown that the performance is improved by increasing the number of antennas at the receiver. The results of this paper can be applied to the applications of UWB.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.39-42
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• 2008

In this paper, we analyze the performance of ultra wide band (UWB) systems in indoor wireless channel in accordance with the number of pulses per bit at transmit signals and the decision types of receiver. The indoor channel is modeled as the modified Saleh and Valenzuela (SV) model which has been proposed as a UWB channel model by the IEEE group, IEEE 802.15.SG3a. Two types of UWB signals are considered One is the pulse position modulation-time hopping (PPM-TH) signal. And the other is the pulse amplitude modulation-direct sequence (PAM-DS) signal. It is assumed that the receiver is an ideal receiver which can receive all signals of the multipath.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1784-1788
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• 2008

전자파표면유속계는 여러 측정지점을 가능한 신속하게 이동하면서 홍수시 유속을 측정하는데 그 목적이 있다. 또한 홍수시 유속은 시간대 별로 급격히 변하는 속성을 가지고 있으므로 유량측정 지점의 유량을 실시간으로 획득하기 위해서는 현장 측정에서 측정한 유량데이터가 실시간으로 집계 되어야한다. 현재의 시스템은 측정 정보를 실시간으로 전송하기 위하여 현장 측정자에게 PDA가 보급되어 있으며 CDMA망을 통해서 유량 측정을 위한 각종 정보 및 측정결과를 실시간 전송하도록 되어있다. 그러나 전자파표면유속계를 비롯한 각종 유속계가 PDA와 무선으로 통신을 할 수 있게 되어있지 않기 때문에 열악한 여건의 현장에서 측정한 데이터를 야장에 수기로 기록한 후 이를 다시 PDA에 수동으로 입력시켜야하는 불편함이 있다. 전자파표면 유속계를 제외한 다른 측정 장비는 제조회사가 수자원공사와 독립적인 업체이므로 통신 접속을 하기위한 특정 인터페이스를 알아내기가 어려운 실정이다. 그러나 전자파표면유속계는 수자원공사에서 개발한 장비로서 핵심기술을 수자원공사에서 보유하고 있으므로 PDA와 통신을 가능하게 하는 장치의 개발이 가능하다. 이에 이러한 불편한 문제점을 개선하여 현장에서 홍수 유량 측정시 작업자들의 편이성을 증대시키고자 전자파표면유속계와 PDA간에 근거리통신기법을 적용하였다. 이를 위하여 Bluetooth, UWB(Ultra-Wide Band, 초광대역통신), Zigbee 등 적용가능한 근거리 통신기법을 조사하였다. 그 결과 Zigbee가 소비전력이 적어 현장에서 홍수유량측정에 이용되는 전자파표면유속계에 적용성이 가장 뛰어난 것으로 나타났다. 무선통신 모듈과 연동되는 전자파표면유속계는 이동식을 기준으로 적용하였으며 기존 신호처리부에 무선통신 모듈을 장착할 수 있는 구조로 설계하였다. 장착 방식은 기존 이동식 유속계의 신호처리부의 RS-232 포트에 무선통신 모듈을 장착하면 사용할 수 있는 구조로 되어있다. 신호처리부 RS-232 포트는 현재까지는 측정한 유속값을 PC로 전송받는 용도로 활용되었으나 무선모듈 장착 시에는 무선통신 할 수 있는 이중화 구조를 채택하였다. 두 가지 방식에 대한 통신구별은 초기에 송수신하는 데이터에 따라 구별되도록 하였다. 신호처리부에서 무선통신 추가에 따른 운용 방식은 별도의 수자원공사 모드를 추가하여 운용하도록 수정하였다. 유속 측정 시에는 무선통신 모듈을 제거한 상태에서 측정한 후, 측정한 데이터를 PDA로 전송할 때 아를 부착하여 사용할 수 있는 구조를 갖도록 제작하였다. 이러한 방식을 적용시킨 이유는 기존에 보급된 유속계에 무선모듈을 장착한 후, 신호처리부 운용 프로그램을 업그레이드하면 바로 사용할 수 있도록 하기 위함이다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.516-521
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• 2005

The application of UWB not only complies with the requirements of remote sensors system(ECG), it also contributes to the effectiveness of the implementations through its unique qualities such as ultra low transmission power - an important factor when dealing with biomedical equipment. In this paper, the aim is to replace the wired ECG sensors with a wireless link and design wireless UWB communication system. The various pulse shapes are presented that satisfies the FCC spectral mask and FCC part 15 rule. It is shown that UWB can be a high rate transmission over short ranges using Rake receiver, with the capability for reliably transmitting 100Mbps over distance at about 10 meters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.561-570
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• 2009

Ultra-wideband communication systems based on impulse radio have merits that are possible for the high data rate transmission, high resolution ranging are positioning system. Conventionally, in order to accomplish these features, the high-speed ADC (Analog to Digital Convertor) is necessary to apply radio determination system operating in time domain. However, considering low rate - wireless personal area network (LR-WPAN) aims to low-cost hardware implementation, the expensive ADC converting GHz sampling per second is not appropriate. So, this paper introduces a low complex AR (Auto Regressive) model based non-coherent ranging scheme operating in frequency domain with using low-speed ADC utilizing analog Voltage Control Oscillator (VCO) mode for the frequency domain transformation. To verify the superiority of the proposed ranging and location algorithm working in frequency domain, the suggested IEEE 802.15.4a TG channel model is used to exploit affirmative features of the proposed algorithm with conducting the simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2C
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• pp.145-152
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• 2009

Ultra-wideband communication systems for impulse radio have merits that are possible for either high resolution ranging system or radio determination. Conventionally, in order to accomplish these functions, the rapid analog to digital convertor (ADC) is necessary to apply radio determination system operating in time domain. However, considering that low rate - wireless personal area network (LR-WPAN) aims to low-cost hardware implementation, the expensive ADC converting GHz sampling per second is not appropriate. So, this paper introduces the high resolution ranging system operating in frequency domain with using low sampling rate ADC, and a new non-coherent ranging scheme utilizing analog Frequency Modulation (FM) mode for the frequency domain transformation. To verify the superiority of the proposed ranging algorithm working in frequency domain, the suggested IEEE 802.15.4a TG channel model is used to exploit affirmative features of the proposed algorithm with conducting the simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.6 s.97
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• pp.556-562
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• 2005

In this paper, we propose interleaved super-orthogonal convolutional coded ultra wide-band impulse radio(ISOC-UWB-IR) system, and analyze its performance. The proposed system uses interleaver and deinterleaver to decorrelate the temporal correlation of the fading process and to obtain the diversity gain. We also suggest the three types of interleavers, which are pulse-wise interleaver(PI), pulse sub-group-wise interleaver(PSGI), and pulse group-wise interleaver(PGI). Performance analysis result shows that the interleaving scheme, rather than the code rate of super orthogonal convolutional code(SOC) encoder, affects the performance for the Rayleigh fading channel.