• International Journal of Contents
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• v.12 no.1
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• pp.65-69
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• 2016

Wireless communication chipsets have fixed transmission rate and communication distance. Although there are many kinds of chipsets with throughput and distance purpose, they cannot support various types of wireless applications. This paper provides theoretic research results in order to support various wireless applications requiring different throughput, delayed quality-of-service (QoS), and different communication distances by using a wireless communication chipset with fixed rate and transmission power. As a performance metric, the probability for a data frame that successfully receives at a desired receiver is adopted. Based on this probability, the average number of transmission in order to make a successful frame transmission is derived. Equations are utilized to analyze the performance of a single-hop with channel coding and a dual-hop without error correction matter transmission system. Our results revealed that single-hop transmission assisted by channel coding could extend its communication distance. However, communication range extending effect of the single-hop system was limited. Accordingly, dual-hop transmission is needed to overcome the communication distance limit of a chipset.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.266-273
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• 2007

In this paper presents the WCDMA(Wideband Code Division Multiple Access) system using the rake receiver over multipath fading and wireless mobile communication environments. The interference between the propagation paths in a multipath fading causes a serious degradation in the wireless mobile communication environments. In order to derive the path interference and reduce the fading effect the rake receiver is used. As a result, the WCDMA system using the rake receiver gives a better performance than the convention WCDMA system over a multipath fading and wireless mobile communication environments.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1408-1415
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• 2007

To operate Platform Screen Door (PSD) automatically, the operational data of PSD and the train must be interfaced properly. PSD and train are operated together by the signaling system in Automatic Train Operation (ATO) signaling system zone where interfaces are provided between PSD and train. However, the additional PSD interface system with train is required in train operating zone without the interface between PSD and train. For the PSD interface, the wireless communication system or the train status (train correct stop status / train door status) detection system has been used. Seoul Metro line No.2. has the PSD wireless communication system using 447MHz band RF. For the safety of PSD operation, it is required to prevent RF interference in the subway environment where many frequencies exist. In this paper, the PSD wireless communication system is developed using 2.4GHz band RF to prevent the interference of the wireless communication and increase the traffic of the PSD interface. Furthermore, the improved system can store, manage and display the PSD and train operational data using Human Machine Interface (HMI) in the train's driver cab.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.4
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• pp.212-220
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• 2014

The current cellular communications are optimized for low mobility users, meaning that their performance is degraded at high speed. Therefore, passengers in a high-speed train experience very poor radio link quality due to the significantly large number of simultaneous handovers. In addition, wireless data traffic is expanding exponentially in trains, subways and buses due to the widespread use of smartphones and mobile devices. To solve the inherent problem of cellular communication networks and meet the growing traffic demand, this paper proposes the mobile hotspot network of a millimeter-wave communication system as a mobile wireless backhaul. This paper describes the physical layer design of uplink and downlink in the proposed system, and the performances of uplink and downlink are evaluated under Rician fading channel conditions. The implemented baseband prototype of the proposed millimeter-wave communication modem is presented. This system can provide a Gbps data rate service in high-speed trains carrying hundreds of wireless Internet users.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.1-10
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• 2023

In this paper, the design and implementation of the long-distance wireless transmission technology of high-definition video using domestic wireless communication technology for the existing wired-based CCTV surveillance system and IP camera system was evaluated for performance. The interworking test between the wireless multi-IP camera transmission terminal device and the wireless communication RF module, and the wireless multi-IP camera-based video transmission system integration interworking test confirm the module interworking suitability during video transmission.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.1-7
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• 2015

The Light Emitting Diode(LED) lighting control system proposed in this thesis is made up of a sensor module, a microcontroller, Bluetooth wireless communication, LED Driver, and LED downlight. The sensor module, comprised of an infrared sensor, an illumination sensor, and a temperature sensor, was designed to one Printed Circuit board(PCB). The system is able to identify the environment information collected by the sensor, and make it possible to control lighting automatically and manually through sensors. In addition, depending on users' conditions, a color temperature can be controlled. CS-1000, a spectroradiometer, was employed to measure the changing values of a color temperature in 8 steps. According to a test, it was found that it was possible to change a color temperature from 3187K of Warm White LED to 5598K of Cool White LED. The Bluetooth based wireless communication technique makes it possible to control more lighting devices than other wireless communication techniques does.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.306-312
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• 2014

The ZigBee communication method, which is the most frequently applied to the LED lighting control system, has drawbacks of low-speed and low-capacity, and the communication failure possibility due to environmental influences is on the rise. Therefore, it is important to secure the communication reliability by applying an integrated interface with a wire-wireless dual-network. This paper developed a communication module, which has a platform converging and combining the ZigBee of USN environments with the PLC of power line communication environments, to implement a dualized communication interface system supporting the wire-wireless integrated protocol, and implemented a wire-wireless networking device and a control system software technology. As a result, it was automatically switched into the PLC communication within 4.4 seconds on average when there was an access failure in the ZigBee communication network, so a reliable communication network was built.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.72-80
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• 2012

Binary CDMA is a new standard technology for wireless communication developed by our country that makes high speed communications and good quality of services. In this paper we researched the design and implementation methods of a wireless CCTV System based on the Binary-CDMA technology that makes it freely installed in any place without cables and laying works. We implemented the hardware and software for the CCTV system and developed a Prototype Wireless CCTV system based on the Binary-CDMA technology.

• ETRI Journal
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• v.36 no.1
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• pp.183-186
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• 2014

In this letter, we consider a cooperation system with multiple untrusted relays (URs). To keep the transmitted information confidential, we obtain joint channel characteristics (JCCs) through combining the channels from the source to the destination. Then, in the null space of the JCCs, jammers construct artificial noise to confuse URs when the source node broadcasts its data. Through a distributed implementation algorithm, the weight of each node can be obtained from its own channel state information. Simulation results show that high-level security of the system can be achieved when internal and external eavesdroppers coexist.

• Journal of Advanced Navigation Technology
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• v.26 no.1
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• pp.1-8
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• 2022

Telemetry system is a system that measures and transmits status information in the aircraft to the ground. The data received from the ground is information for monitoring the state of the aircraft, and can be checked and analyzed in real time through the test program. Data processing test system for telemetry currently in operation is built to transmit data using wired communication and perform test. As smart devices become popular due to the continuous development of information and communication technology, wireless communication networks are becoming important, and technologies for improving performance are steadily being developed. In this paper, we suggests and builds data processing ground test system for telemetry using wireless communication(Wi-Fi) that can be checked through smart devices such as tablets, in order to break away from the existing method and apply future-oriented technology. Finally, the suggested test system performance was proved by testing in various environments by linking test equipment and test program.