• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1680-1684
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• 2010

CBTC(Communication-Based Train Control) system which is based on wireless communication can provide high density operation of the train using location tracking between ground and onboard train. It can also reduces maintenance expense because it does not require the ground equipment for tracking circuit and signal flag and so on. Recently, research and interest have been done on CBTC system. The high-speed trains up to 300km/h experience multi-path fading channel which bring about the performance degradation of wireless CBTC system. In this paper, we consider MIMO (Multi-Input Multi-Output) antenna-based CBTC system for trains with Alamoutip-type space-time diversity transmission for reliable communication. Also we model a channel considering practical environment and evaluate performance improvement of proposed CBTC system.

• Journal of the Korean Society for Railway
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• v.17 no.6
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• pp.402-409
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• 2014

Wireless local area network (WLAN) is a widely used wireless access method due to its easy usability and excellent performance. However, its performance degrades significantly as the number of users increases. In busy train stations, where the number of WLAN users are large and, more importantly the number of simultaneous packet transmission attempts is extremely large due to the time synchronization upon train arrival, the packet transmission delay problem is very severe and almost impossible for WLAN stations to initiate communication with WLAN networks. In this paper, a novel distributed WLAN access scheme for efficient WLAN communication in busy train stations is proposed. Using the proposed scheme, WLAN access delay can be significantly reduced under highly congested traffic environments. Therefore, a significant performance enhancement for the WLAN performance used in the Communication Based Train Control (CBTC) can be achieved.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2735-2744
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• 2011

Korean-Automated Guideway Transit (K-AGT) was successfully developed through Light Rail System Development Project. Since then, the domestic development rate of on-board signalling system of light rail has been improved up to 90% by Practical Utilization Project of Light Rail. After utilization project, furthermore, POSCO ICT has developed the wayside signalling system of CBTC, including wireless communication equipment. KRRI carried out the performance test of the wireless communication, interfacing and using the other CBTC equipments of KyungSan Test Line so as to see whether it conforms IEEE 802.11x, international communication standard in view of operational concept of CBTC. In this paper, we presents analysis results of roaming test while train runs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.51-58
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• 2019

The LTE system decided to build an integrated disaster safety communication network in order to cope with disasters quickly after the April 16, 2014 disaster, and 333 agencies in 8 areas will build a unified disaster safety communication network. It plans to integrate LTE-R, a railway integrated wireless network, and LTE-M, a land-based communication network, in the 700MHz band. LTE-R, a wireless integrated network, and the Ministry of Land, Transport and Maritime Affairs, are currently using VHF and TRS, which are voice communication-oriented communication systems, in order to cope with demand for high-speed railway service, With this possible LTE-R, it is possible to provide advanced services such as radio-based train control and improve railway safety. The company plans to invest KRW 1.1 trillion in new routes to be launched in 2018 and the existing route to be improved in the future, and to build up all routes of general and high-speed railways to LTE-R by 2027.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.149-156
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• 2012

This paper suggests the data transmission technology for applying to the actual railway line based on the technological trends and theories for the wireless Mesh techniques. This paper presents a technical basis that is applicable to the economic and efficient use of frequency and to the development of a Communication Based Train Control System by demonstrating its Applicability, Availability, Reliability and Safety for the train control system of the radio frequency of the bandwidth of 5.7 GHz at the experiments.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.347-351
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• 2008

This study is concerned with the design of the communication based evaluation simulator for the development of the operational control algorithm for PRT(Personal Rapid Transit) system which has very short headway and requires accurate speed control of the vehicles to avoid the impact between the vehicles. The evaluation simulator is composed of central control system, vehicle control system, communication control system, AP for wireless communication, and monitoring system. For the mobile characteristics of the PRT vehicles wireless communication is employed for the transmission of the control and status information between the central control system and the vehicle control system. By using simple test operational control algorithm the effectiveness of the proposed evaluation simulator is shown.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.512-515
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• 2019

Overhead contact systems (OCS) consist of contact and messenger wires, in which the contact wire supplies electric energy to the railway vehicle by contacting a pantograph. However, this mechanical contact is interrupted during frosts or temperatures below $0^{\circ}C$ in the winter. In these conditions, railway vehicle accidents can occur during operation because of the low energy efficiency that results from the increase in the arcing between the contact wire and pantograph. Therefore, the detection of frost or freezing temperatures is necessary to maintain the stable operation of these trains. In this study, we proposed the development of a frost or freezing condition monitoring system on the OCSs that utilizes wireless communication.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.82-87
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• 2005

The new technology with Wireless LAN (WLAN) is implemented to the railway system, which is attached importance to safety and reliability. Railway control system based on WLAN that is called CBTC (Communication Based Train Control) is being developed by the advanced nations in this field and The system is applied to a new train line and a renovation for outworn equipment. The CBTC system has many merits about increase of capacity, reduction of headway and cost reduction etc.. Therefore, that is come into spotlight to the advanced railway company and the companies have being developed the system. So, we have developed the CBTC system for standardization and localization of the railway signal system.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.521-528
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• 2022

The beginning of a new railroad history is progressing every year. Seoul's Sillim Line is a new transportation system based on communication technology. Sillim Line is the nation's first wireless communication-based unmanned train control system based on KTCS-M, the national standard. The use of wireless communication technology in the rail transportation system suggests the possibility of exporting to the global rail market. This is the result of the government's development and implementation of various support policies for nurturing the domestic railway industry and for export. In this paper, the status of support for localization of railroad industry technology implemented by the state is reviewed, and the process by which railroad parts are replaced by localized parts is analyzed out of dependence on foreign countries. A study was conducted on the development of a technical support platform to solve the technical difficulties of the industry that occurred in this process.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2755-2761
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• 2011

The purpose of this study was to analyze and improve the communication interferences in the wireless communication equipments of the CBTC applied to a model intelligence train control system. So far, train positions have been traced by the conventional fixed blocking system to control the operation of the trains, but the new CBTC system uses the on-ground location to transmit the train positions wirelessly to the ground control center continuously, so being more vulnerable to communication interferences. Although the researcher analyzed and improved such interferences in the communication equipments of the CBTC system, there remain more rooms for its improvement.