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테스트베드상에서 LTE기반 철도 무선통신시스템의 성능 측정
김범곤(Bum Gon Kim),권병희(Byung Hee Kwon),조한벽(Han Byeog Cho),조웅(Woong Cho) 한국전자통신학회 2017 한국전자통신학회 논문지 Vol.12 No.5
철도통신에서 데이터의 전송속도를 향상시키고 신뢰성 있는 데이터 전송을 위해 LTE기반 철도 무선통신시스템에 대한 연구가 진행되고 있다. 본 논문에서는 LTE기반의 철도 무선통신시스템의 테스트베드에 대해 소개한다. 테스트베드상에서 무선통신시스템을 이용하여 전계강도, 통신 도달거리, 통화설정시간, 핸드오버 성공률, 데이터 전송속도 등과 같은 기본적인 통신성능 측정결과에 대해 소개한다. 이 결과를 바탕으로 향후 시스템 상용화에 필요한 사항들에 대해 논의한다. In railway communication, LTE based railway wireless communication systems have been developed to support high data rate and reliable communication link. In this paper, the testbed of LTE based railway wireless communication systems is introduced. Then, we describe measurement results of communication performance such as radiation strength, communication coverage, call setup time, handover success rate, and data transmission rate in the testbed. We also consider requirements for commercialization based on measurement results.
Error Correction by Redundant Bits in Constant Amplitude Multi-code CDMA
송희근,김성만,김범곤,김동석,고대원,김용철,Song, Hee-Keun,Kim, Sung-Man,Kim, Bum-Gon,Kim, Tong-Sok,Ko, Dae-Won,Kim, Yong-Cheol The Korea Institute of Information and Commucation 2006 韓國通信學會論文誌 Vol.31 No.11C
In this paper, we present two methods of correcting bit errors in constant amplitude multi-code (CAMC) CDMA, which uses the redundant bits only. The first method is a parity-based bit correction with hard-decision, where the received signals despread into n two-dimensional structure with both horizontal parity and vertical parity. Then, an erroneous bit is corrected for each $4{\times}4$ pattern. The second method is a turbo decoding, which is modified from the decoding of a single parity check product code (SPCPC). Experimental results show that, in the second method, the redundant bits in CAMC can be fully used for the error correction and so they are not really a loss of channel bandwidth. Hence, CAMC provides both a low peak-to-average power ratio and robustness to bit errors.
김성만(Sungman Kim),오태석(Taesuk Oh),김범곤(Bum Gon Kim),송희근(Hee Keun Song),김용철(Yong Cheol Kim) 한국방송·미디어공학회 2006 한국방송공학회 학술발표대회 논문집 Vol.2006 No.-
본 논문은 AWGN 채널상의 Single Parity Check(SPC) 다차원 product부호에서 LDPC(Low Density Parity Check)부호를 이용한 오류 정정의 성능을 제시한다. 기존 방법인 터보 부호 방식을 이용한 오류 정정과 비교하여 LDPC부호가 갖는 장점을 기술하고 실험을 통해 LDPC 부호를 이용한 오류 정정 성능도 터보부호와 대등함을 보인다.
조웅(Woong Cho),김범곤(Bum Gon Kim),조한벽(Han Byeog Cho) 한국전자통신학회 2017 한국전자통신학회 논문지 Vol.12 No.1
중계기는 송신기에서 수신기로 신호를 전송할 때 통신반경을 확장시키고 음영지역을 제거시키는 장점 때문에 다양한 무선통신 시스템에서 적용이 가능하다. 본 논문에서는 철도환경에서 중계기를 사용하는 듀얼홉 통신시스템을 적용하여 하향링크에서의 성능을 분석한다. 통신방식은 기지국에서 중계기사이에서는 동기변조방식을 사용하고 중계기에서 수신기 사이에서는 차등변조방식을 사용하는 비대칭 전송방식을 적용한다. 시스템의 성능은 심벌오류율을 이용하며 분석하며 전체시스템이 동기방식을 이용하는 시스템과의 성능을 비교한다. 중계기 거리 및 에너지할당에 따른 성능 또한 분석한다. Due to the advantage of communication coverage extension and removement of shadowing area, relay can be applied in various wireless communication systems. In this paper, we analyze performance of downlink with dual-hop communication systems which use a relay in railway environments. We adopted asymmetric communication system which use coherent modulation scheme in base station-relay link and differential modulation scheme in relay-destination link. The performance of communication system is analyzed using symbol error rate, and performance comparison with the systems which adopts fully coherent scheme is studied. We also investigate the performance of system depending on relay distance and energy allocation.
김석희(Seok Hee Kim),유영규(Young Kyu Yu),김범곤(Bum Gon Kim) 한국사회체육학회 2007 한국사회체육학회지 Vol.0 No.30
The purpose of this study was to suggest development/test of measurement and evaluation in tools for evaluation of section motion in tennis serve, investigate reliability of measurement and evaluation in tools and, difference according to a pattern and a special level of tennis serve. Development of measurement and evaluation in tools was completed second, third evaluation in tools of proved validity through the expert group of tennis, after make out first a reserve evaluation in tools as a foundation study of tennis serve in the past days. Research evaluators were some of 10 students of ``M`` university who major in physical education and research subjects were some of 8 general person. First, measurement and evaluation in tools were developed through the literature study and the expert group of tennis. It`s composed to easy, simple word and make a score measure(table 4). Second, results from analysis of reliability of evaluation in tools according to evaluators. It isn`t statistically significant difference. Third, results from analysis of reliability of subjects according to evaluation in tools. And the section motion in tennis serve according to subjects showed a statistically significant difference(p<.001). It`s appeared that the results form Tukey hoc post test in order of elementary grade<middle grade<high grade. Fourth, results from analysis of make a score ranking of the section motion in tennis serve of subjects according to level. Elementary grade was appeared that in order of finish→toss→ready position→impact→back swing→follow through→forward 2→forward 1. Middle grade was appeared that in order of ready position→finish→impact→toss→follow through→back swing→forward 2→forward 1. High grade was appeared that in order of toss→impact→forward 2→forward 1→finish→ready position→back swing→follow through.
고속철도 AF궤도회로경계구간 케이블길이 변화에 따른 전기특성 분석연구
최재식(Choi, Jae Sik),김희식(Kim, Hie Sik),박주훈(Park, Ju Hun),김범곤(Kim, Bum Gon) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.7
본 논문은 2004년 경부고속선 개통이후 UM71C AF궤도회로 현장 구성품(BU, SVaC, DB)들이 선로내측 자갈도상에 설치되어 있기 때문에 겨울철 고속차량 낙빙 및 시설분야 장비작업으로 인한 파손사례가 자주 발생되어 시설물 보호를 위한 개선대책일환으로 선로내측에 설치된 구성품을 선로외측으로 이설할 경우 케이블 길이 변화에 따른 임피던스 특성변화와 보상콘덴서 추가구성을 위하여 MATLAB Simulink를 이용하여 시뮬레이션을 시행하였고 또한 고속선 현장실증시험을 통하 여 시뮬레이션과 동일한 결과를 얻었다. 향후 궤도회로사구간에 대한 보완과 구성품내부 임피던스 재설계 연구를 통하여 실제 현장에 적용될 수 있을 것으로 기대된다. It has been often occurred for the outside components(BU, SVaC, DB) of UM71c AF track circuits to be broken down caused by some pieces of falling ice in the winter time or by infrastructure repairing equipments while facility maintenance works since 2004, opening of Kyeongbu High Speed Rail Express. In this paper, we proposed that we could move the outside components of UM71c track circuit out of wayside from present place. Then we can assure that the life time of those components would be extended. So we simulated the electrical characteristics by changing cable length using MATLAB Simulinks and we designed the compensation capacitor. Also, we obtained the same results as those of simulation by field demonstration test on site. The design specifications obtained from this field verification test could be applied in the absent section of track circuit, if only have a little more intensified research to compensate changed electrical characteristics and to redesign inner impedance of the track circuit.
KTX 산천운행시 발생되는 전자파노이즈에 대한 AF궤도회로(TI-21) 신뢰성 확보방안 기술연구
최재식(Jae-Sik Choi),이시빈(See-Bin Lee),김범곤(Bum-gon Kim),이태훈(Tea-Hoon Lee),고준영(Joon-Young Ko) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.5
KTX산천차량이 국내기술로 개발되어 현재 경부고속철도와 기존선구간인 경부선과 호남선, 경전선을 운행하고 있다. 2010년 KTX산천 영업시운전 당시 일반철도구간 경부선 및 호남선 하선구간 운행시 반대편 인근 상선의 특정한 궤도회로(AF궤도회로 “C” TYPE)가 오동작하여 신호기가 정지하는 현상이 발생하였으며 이에 대한 해결방안으로 “ C ”type AF궤도회로 수신기에 대해 노이즈 해석능력을 갖춘 디지털방식으로 개선하여 현재는 이와 같은 오동작 현상은 더 이상 발생하지 않고 있다. 본 논문에서는 개선된 궤도회로 수신기의 전자파노이즈 분해능력 원리, 시험 및 검증방법에 대하여 논하고자 한다. KTX-Sancheon, developed with Korean Technology, has been operated on Gyeongbu, Honam, Gyeongjeon normal lines and Geongbu high speed line. When the high speed trains were made a trial run on Gyeongbu and Honam downbound normal lines in 2010, The signals stop occurred since specific track circuits such as C type AF track circuits didn’t work properly on the upbound line opposite. To deal with this problem, we improved C type AF track circuit receivers from analog into digital type which have a noise analysis function so that the problem didn’t occur any longer. In this paper, we aimed at defining principles, a test and a way of verification about electromagnetic noise analysis function of the improved track circuit receivers.