• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1023-1026
• /
• 2007

CBTC (Communication Based Train Control) is a railroad system, using wireless communication for data transmission between on-board units and ground units, that makes ground computer periodically collect position and speed data from each train and transmits the preceding train's distance data up to speed limit point so as to make on-board control unit control the optimum train speed. Due to the fact that wireless communication system for train control employs only limited frequency band and output frequency, a number of ground communication units should be installed at track-side; also a running train should carry out Handover function which maintains the communication by accessing a new communication channel of the adjacent on-board communication units in accordance with the output of received radio wave. Especially CBTC is largely dependent on Handoff function between ground communication units. Therefore, this paper provides the method of identification of hazard between ground communication units and on board units.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.406-410
• /
• 2009

Power facilities of urban rail transit substation is deterioration, and endurance limitation is coming, so urban rail transit facilities should take any necessary measure for maintenance and repair. In this paper proposes online monitoring system using the wireless communications for the urban rail transit. This system is constructed various departments; such as sensor, measurement, data communication, host computer, and power departments. It is designed to collect and save AI (Analog Input) information of the power facilities, and to analyze and display them. As a result, it is possible to prevent from any unexpected power cuts and monitor my abnormalities in real time, and to collect accumulated data for creating a better management system.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1756-1760
• /
• 2008

In this study, it was suggested how to monitor the air quality with use of intelligent wireless sensor network in the subway station. When Zigbee-based ubiquitous sensor network was used, smaller budget was required in configuring the system compared to existing air-quality monitoring method and this system may easily be configured due to easy installation of communication cables. The study will be continued to supplement the network systems currently installed in subway stations and the completion of development of this system is expected to make a large contribution in improvement of indoor air quality.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1138-1144
• /
• 2008

To study the feasibility of applying wireless communication technology to the control of train for the effective control of train and for the reduction of cost and time to construct the necessary infra structure, we investigate into the application of the existing commercial WCDMA network to CBTC (communication-based train control) to grasp the obstacles and propose the solutions to circumvent them. The obstacles can be categorized into the hand-off problem, the interference problem near the stations, and the problem of radio shadow areas. We propose, as solutions, the cell overlap method and multi-terminal approach for the hand-off problem, the cell sectoring method for the interference problem, and establishment of new base stations along the railroad both to provide the wireless train control and communication service to the customers on the train which was otherwise impossible because of the shadowing effect.

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

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.9
• /
• pp.4240-4258
• /
• 2016

A practical iterative channel estimation technique is proposed for the multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system in the high-speed mobile environment, such as high speed railway scenario. In the iterative algorithm, the Kalman filter and data detection are jointed to estimate the time-varying channel, where the detection error is considered as part of the noise in the Kalman recursion in each iteration to reduce the effect of the detection error propagation. Moreover, the employed Kalman filter is from the canonical state space model, which does not include the parameters of the autoregressive (AR) model, so the proposed method does not need to estimate the parameters of AR model, whose accuracy affects the convergence speed. Simulation results show that the proposed method is robust to the fast time-varying channel, and it can obtain more gains compared with the available methods.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1106-1111
• /
• 2010

Conventional traffic network in the urban city has been constructed and operated under systems to collect and transmit based on the roadside AP(Acess Point). But This paper has investigated the new traffic network based on smart station which combined the power network. Futhermore, the smart station can collect and transmit the variable informations and functions that supply the vehicle moving lines, informative collector service and center interoperation etc.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1441-1444
• /
• 2009

In this paper a platform that makes it possible the simulations of the vehicle operational control for PRT (Personal Rapid Transit) is introduced. PRT system has very short headway and requires accurate speed control of the vehicles to avoid the impact between the vehicles. The proposed platform is composed of central control system, station control system, communication control system, AP for wireless communication, and monitoring system. Simple operational test scenarios are presented and the effectiveness of the proposed platform is shown using the test scenarios.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.1543-1548
• /
• 2008

Ubiquitous technology is the trend towards increasingly ubiquitous, connected computing devices in the environment, a trend being brought about by a convergence of advanced electronic - and particularly, wireless - technologies and the internet. Ubiquitous technology is pervasive in nature and unobtrusively embedded in the environment, completely connected, intuitive, effortlessly portable, and constantly available. The object of this paper is to describe the strategy plan for Ubiquitous-Urban Transit Total Information System.

• Proceedings of the KSR Conference
• /
• 2003.05a
• /
• pp.480-486
• /
• 2003

This paper proposes the connection without cables among display devices in a train using piconet of the Bluetooth. Nowadays, each train has a number of the display devices that are connected with many cables to lead the passengers, so it has the waste of resource and factor of fault. This paper proposes the improvement schemes of those problems in a train using piconet of the bluetooth with low cost, low power, and high security.