18GHz 지하철 무선영상 전송시스템 개발

정상국(Jeong, Sang-Guk),안태기(An, Tea-Ki),김백현(Kim, Baek-Hyun),남명우(Nam Myung-Woo),이영석(Lee, Young-Seok),오명관(Oh Myoung-Kwan) 한국산학기술학회 2010 한국산학기술학회논문지 Vol.11 No.6

지하철 운행 중 차지상간 무선영상전송을 위해 18GHz 대역을 이용한 OFDM 방식의 영상 전송 시스템을 개발하였다. 개발된 시스템은 디지털 변조 보드와 RF 보드로 구성하였으며, 지하철 터널구간 내에서 18GHz의 멀티 패스 페이딩에 강한 특성을 가진다. 시스템의 검증을 위하여 스펙트럼 분석기를 사용해 전송 시스템의 출력 신호를 분석하였고, 분석결과 구현된 시스템은 350MHz에 대역폭 8MHz, -19dBm의 채널 파워를 가짐을 확인할 수 있었다. 또한, 영상의 송·수신 특성을 시험하기 위하여 SR사의 MPEG-2엔코더를 사용하여 영상을 입력하고 송신한 후 SR사 의 수신기를 이용하여 영상 수신 실험을 하였다. 실험결과 송신한 영상이 손실 없이 수신됨을 확인하였다. The video transmission system using OFDM method at 18GHz frequency band was developed for wireless video transmission from subway to monitoring center when subway running. It is composed of digital modulation board and RF board. And it has a robust characteristics of multipath fading in subway tunnels at 18GHz. To verify the system, we used spectrum analyzer for analysing the output of transmission system and get the results that it has 350MHz frequency, 8MHz bandwidth and -19dBm channel power. Also we tested video receiving using MPEG-2 encoder and got good quality images.

지하철 터널에서의 18GHz 무선영상신호 전파특성 측정

최규형,서명식 한국철도학회 2012 한국철도학회논문집 Vol.15 No.4

This paper presents an experimental study on the radio propagation characteristics in subway tunnel at 18GHz frequency band which has been assigned to video transmission between train and wayside. The radio propagation tests are carried out in the subway tunnel of Seoul Metro using the antenna and communication devices of the prototype video transmission system. The measurement results show that 18GHz radio propagation in subway tunnel has smaller path loss than that of general outdoor radio environment. It is also cleared that the arch-type tunnels have smaller radio propagation losses than rectangular tunnels, and single track tunnels have smaller pass loss than double track tunnels. From the measurements, the radio propagation coverage is worked out as 520 meters. The curved tunnels which cannot have LOS communication between transmitter and receiver have large pass losses and fluctuation profile along distance. The radio propagation coverage along curved tunnels is worked out as 300 meters. These investigation results can be used to design the 18GHz radio transmission system for subway tunnel by providing the optimized wayside transmitter locations and handover algorithm customized to the radio propagation characteristics in subway tunnels.

고속이동체를 위한 OFDM Ethernet 모뎀 시스템 구현

정상국(Jeong, Sang-Guk),안태기(An, Tea-Ki),김백현(Kim, Baek-Hyun),남명우(Nam Myung-Woo),이영석(Lee, Young-Seok),오명관(Oh Myoung-Kwan) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.4

도시철도 분야에서 멀티미디어 전송을 위하여 18GHz 대역에서 영상전송을 위한 OFDM변조 방식이 이용되 고 있다. 양방향으로 영상뿐만 아니라 이더넷 데이터를 전송하기 위한 응용분야가 크게 늘고 있다. 도시철도 분야에 적용된 18GHz분야는 멀티패스페이딩에 영향이 크므로 OFDM캐리어 개수가 큰 경우가 유리하다. 그러나 이더넷 전송 이 가능한 기존 WLAN의 경우 캐리어의 개수가 64개로 원거리 고속이동에 적합하지 않다. 따라서 본 연구에서 고속 이동체에서 고속데이터 전송에 적합한 2,000 캐리어의 OFDM 이더넷 모뎀을 구현하고 검증하였다. 고속이동에서 도 플러효과를 상쇄하기 위하여 도플러보상 블럭을 구현하였다. 도시철도 및 고속철도 분야에서 기술의 활용이 크게 기대 된다. OFDM Modulation is used for multimedia transmission At Urban Train. Recently the application field about data transmission is expanding the image as well. The case which the number of OFDM carrier is big is advantageous because multipass fading is big 18GHz wireless frequency. Existing WLAN which an ethernet transmission is possible is not suitable to a great distance transmission because number of carrier is 64. In this paper, we developed OFDM modem suitable to transmit broadband data at high speed train. A doppler compensation block added to offset the doppler effect. Therefore, the effectiveness is expected to be very big in field of urban train.

Ku 밴드 수신단을 위한 저잡음 증폭기 및 주파수 혼합기 설계

최혁재(Hyuk-Jae Choi),고재형(Jae-Hyeong Ko),김군태(Koon-Tae Kim),이제광(Je-Kwang Lee),김형석(Hyeong-Seok Kim) 대한전기학회 2012 전기학회논문지 Vol.61 No.2

The Ministry of Information-Communication assigned 18~19GHz frequency band for communication of cabins and platform to link between subway/train and it"s station. In this paper, we propose wireless transmission devices which are 2 stage hybrid low noise amplifier of 18GHz band and mixer for 18GHz as well to apply for RF receiver. We designed LNA to be noise matched its 1st stage and gain matched for 2nd stage and mixer using 180° hybrid coupler to suppress the spurious signal. The transistors of 18 GHz LNA and mixer are NE3210S01 of NEC and KMB-N51-1, respectively. As the result of simulation, we get 19.92dB gain and 2.06dB noise figure with LNA and 8.61dB conversion loss with mixer.

지하철/열차 무선 영상전송을 위한 18GHz 대역의 RF 중계기에 적용 가능한 2단 저잡음 증폭기 설계

최혁재,이제광,권소현,김형석 한국정보통신설비학회 2010 한국정보통신설비학회 학술대회 Vol.2010 No.1

A Study on the Design of Full-LTS 18-GHz ECR Ion Source for Heavy Ion Accelerator

Shaoqing Wei,Sangjin Lee,Sukjin Choi Institute of Electrical and Electronics Engineers 2016 IEEE transactions on applied superconductivity Vol.26 No.4

<P>An electron cyclotron resonance (ECR) ion source is an essential component of the heavy ion accelerator. The intensity of the highly charged ion beams extracted from the source can be increased by enlarging the physical volume of the ECR zone, which is one of the key elements of the ECR ion source. The ECR zone locates in a minimum B field configuration that is created by solenoids and hexapole. For an 18-GHz ECR ion source, hexapole is generally made by a permanent magnet. In this paper, a low-temperature superconductor (LTS) magnet was used instead of a permanent magnet because its cost becomes higher and higher, and finally, the mechanical stress of hexapole would be enhanced. First, the hexapole-in-solenoid system and the solenoid-in-hexapole system with several numbers of solenoid coils were analyzed. Then, the most appropriate arrangements for ECR systems were selected. The total length of LTS wire was minimized with the ECR zone volume and the maximum magnetic field in hexapole, respectively, using the evolution strategy method. Finally, the optimized design for a full-LTS 18-GHz ECR ion source was presented.</P>

A study on the design of hexapole in an 18-GHz ECR ion source for heavy ion accelerators

Wei, Shaoqing,Zhang, Zhan,Lee, Sangjin,Choi, Sukjin The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.2

High charge state electron cyclotron resonance (ECR) ion source is important on the performance of heavy ion accelerators. In this paper, a low temperature superconductor (LTS) was used to make a hexapole coil for an 18-GHz ECR ion source. Several hexapole structures, including racetrack, graded racetrack, and saddle were implemented and analyzed for the hexapole-in-solenoid ECR ion source system. Under the appropriate radial confinement field, the smaller outer radius of hexapole can be better for the solenoid design. Saddle hexapole was selected by comparing the wire length, maximum outer radius of the hexapole, the Lorentz force at the end part of the hexapole and the maximum magnetic field in the coil. Based on saddle hexapole, a new design for hexapoles, the snake hexapole, was developed in this paper. By comparative analysis of the Lorentz force at the end part of the saddle and snake hexapoles, the snake hexapole is much better in the ECR ion source system. The suggested design for the ECR ion source with the snake hexapole is presented in this paper.

A study on the design of hexapole in an 18-GHz ECR ion source for heavy ion accelerators

Shaoqing Wei,Zhan Zhang,Sangjin Lee,Sukjin Choi 한국초전도저온학회 (구 한국초전도저온공학회) 2016 한국초전도저온공학회논문지 Vol.18 No.2

터널환경에서 18GHz 대역신호의 전파경로손실 예측 시뮬레이터 개발

안태기(An, Tea-Ki),김백현(Kim, Baek-Hyun),남명우(Nam Myung-Woo),이영석(Lee, Young-Seok),정상국(Jeong, Sang-Guk),오명관(Oh Myoung-Kwan) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.4

본 논문에서는 지하 터널환경에서 전파의 경로 손실 특성을 예측할 수 있는 시뮬레이터를 개발하였다. 전파 의 경로를 정확히 분석하기 위하여 image theory 방법을 이용하였으며, 직선 터널 구간뿐만 아니라 곡선 터널 구간에 서도 전파 손실을 예측할 수 있도록 구현하였다. 시뮬레이터는 다양한 변수들을 입력받아 실시간으로 전파 경로를 도 식화하여 결과를 보여줄 수 있으며, 송신부와 수신부의 위치를 변경하며 결과를 예측할 수도 있다. 개발된 시뮬레이 터의 결과는 충훈 터널에서 실측한 전파 경로 손실 데이터와 비교 분석하여 타당성을 확인하였다. In this paper, the radio propagation path loss prediction simulator in tunnel was developed. It used a image theory method for analysing precise radio propagation path. And it can predict radio propagation path loss in straight and curved tunnels. The simulator can plot realtime radio propagation paths using various parameters which was input by user. And it can simulate from changing transmitter and receiver positions. The predicted path loss of simulator was compared with the measurements in Chunhyun tunnel and confirmed the validity.

무인열차운행을 위한 유 · 무선 감시시스템 개발 현황

이강미(Kang Mi Lee),이재호(Jae Ho Lee),권민정(Min Jung Kwon) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.5

무인열차운행이 확대됨에 따라, 운행선로의 침입감시를 위한 선로감시시스템, 운행중인 열차내 보안 및 승객 안전을 위한 열차내 감시시스템의 필요성이 확대되고 있다. 전라도 일로역과 대불역 약 12km 구간에서는 무선기반 열차제어시스템의 성능평가를 위한 시험선과 시험차량이 운행 중에 있으며 이와 함께 선로변 및 차내 승객 안전을 위한 유무선 감시시스템이 개발 및 시험평가 중에 있다. 유선 감시시스템은 선로변 침입 및 선로유지보수자 감시를 위한 영상확보가 가능하도록 설계 및 제작되었고, 무선감시시스템의 경우, 지하철 무선영상전송용 전용주파수대역인 18GHz 무선시스템 및 상용무선시스템을 이용하여, 차-지상 영상정보전송이 가능하도록 구축되었다. 본 논문에서는 대불시험선에 구축된 유무선 감시시스템 개발 현황에 대하여 기술한다. As driverless train operation has been expanded, there is a growing need for onboard monitoring system for invasion into operational line, onboard security of operational train and passenger safety. Test lines and test rolling stocks are in operation about 12km between Illo and Daebul stations in Jeonlla-do in order to evaluate performance of wireless train control system and wire and wireless monitoring system is under development and test evaluation for trackside and onboard passenger safety. Wire monitoring system has been designed and produced in order to allow obtainment of images for monitoring trackside invasion and line maintenance workers. For wireless monitoring system, it is possible to transfer images between onboard and ground by using wireless system with 18GHz, the exclusive frequency band for wireless transmission of train images and commercial wireless system. This paper describes current development of wire and wireless monitoring system established on the Daebul test line.