• 한국공간정보시스템학회 논문지
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• 제6권2호
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• pp.77-84
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• 2004

본 연구의 목적은 유선통신망으로만 구성되어 있는 국가 ITS 물리 아키텍쳐의 노변장치요소와 센터 구성요소간의 통신망에 무선통신시스템을 전면적으로나 부분적으로 적용하여 시스템 성능 개선과 통신비용을 절감할 수 있는 효과적인 가이드라인을 제시하는 것이다. 이를 위해 국도교통관리시스템에서 사용하고 있는 기존의 유선통신망 뿐만 아니라 무선 LAN 및 위성데이터 통신 등 무선통신시스템의 교통데이터 수신과 전송방법들을 현장실험을 통해 비교 분석하였다. 또한 각 통신 방식별 통신비용을 분석하여 국가 ITS 시스템에 효과적으로 적용될 수 있는 가능성을 알아보았다. 본 연구 결과는 향후 지자체나 도로공사 등 타 ITS 시스템 구축과 운영에 활용될 수 있을 것이다.

• International Journal of Control, Automation, and Systems
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• 제6권1호
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• pp.119-125
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• 2008

This paper examines the use of a wireless Fieldbus based on IEEE 802.15.4 MAC protocol. The superframe of IEEE 802.15.4 is applied to a transmission scheme of real-time mixed data. The transmission and bandwidth allocation scheme are proposed for real-time communication using a superframe. The proposed wireless Fieldbus protocol is able to transmit three types of data (periodic data, sporadic data, and non real-time messages), and guarantee realtime transmission simultaneously within a limited timeframe.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.2035-2051
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• 2011

Theoretical Bit Error Rate (BER) and channel capacity analysis are always of great interest to the designers of wireless communication systems. At the center of such analyses people are often encountered with a high-dimensional multiple integrals with quite complex integrands. Conventional Gaussian quadrature is inefficient in handling problems like this, as it tends to entail tremendous computational overhead, and the principal order of its error term increase rapidly with the dimension of the integral. In this paper, we propose a new approach to calculate complex multi-fold integrals based on the number theory. In contrast to Gaussian quadrature, the proposed approach requires less computational effort, and the principal order of its error term is independent of the dimension. The effectiveness of the number theory based approach is examined in BER and capacity analyses for practical systems. In particular, the results generated by numerical computation turn out in good match with that of Monte-Carlo simulations.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.459-463
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• 2001

We model and simulate master-driven TDD wireless communication systems, e.g., Bluetooth systems. We model the Bluetooth system and use the BONeS simulation tool to conduct event-drivers simulations. In order to support more than seven slave devices in a piconet, a park mode is considered and modeled. We evaluate the performance, i.e., throughput and delay, using simulations when multi-connections (bath ACL and SCO connections) are present in a piconet. We show that the data rate of ACL connections may be less than 20 kbps when SCO connection(s) and more than six ACL connections are jointly supported in a piconet. In addition, if up to five ACL connections are supported, the average delay is shown to be maintained less than 20 msec. Our results can serve as a guideline to the design of master-driven TDD wireless communication systems with performance requirements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2540-2542
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• 2002

In recent years, it is a worldwide trend that many power utilities focus their attention to employ up-to-date communication technology to the automation of their power plants and distribution systems. Automation Systems in Korea was installed using twisted pair cable(TPC), power line carrier(PLC), coaxial cable(CA), wireless network(wireless data, TRS and PCS). Among the communication media only Satellite Communication guarantees the reliable communication in case of emergency such as a flood, a heavy snow and an earthquake. It can integrate two-way satellite systems to existent nationwide SCADA controlling points of electric power transmission & distribution system that enables real time remote monitoring and controlling automatically. This paper presents some of design efforts for the satellite communication network as the media of Automation Systems.

• 전기학회논문지P
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• 제64권2호
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• pp.50-56
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• 2015

This paper presents a smart monitoring technique for photovoltaic power systems by using wire and wireless communication networks in which the RS-232/484 and the Zigbee communication networks are inherently established respectively. In the proposed monitoring systems, environmental data sequences and the output power measured by sensors in photovoltaic systems are transferred to PC systems via two communication networks. We made electronic hardware boards for sensors and communication networks to construct its real-time monitoring system and carry out experiments for demonstrating reliability of the proposed monitoring system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.2946-2962
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• 2017

An improved energy-efficient compressed network coding method is proposed for the data communication in the wireless sensor networks (WSNs). In the method, the compressed sensing and network coding are jointly used to improve the energy efficiency, and the two-hop neighbor information is employed to choose the next hop to further reduce the number of the transmissions. Moreover, a new packet format is designed to facilitate the intermediate node selection. To theoretically verify the efficiency of the proposed method, the expressions for the number of the transmissions and receptions are derived. Simulation results show that, the proposed method has higher energy efficiency compared with the available schemes, and it only requires a few packets to reconstruct measurements with reasonable quality.

• 한국ITS학회 논문지
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• 제8권6호
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• pp.73-81
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• 2009

무선 매체로의 전송은 유선 매체로의 전송에 비해 낮은 신뢰성과 전송의 안정성이라는 단점을 갖는다. 이를 위한 하나의 대안으로 협업 통신의 다이버시티 효과와 채널 코딩 방법을 통한 오류 정정 효과를 사용하고자 한다. 본 문에서는 전송의 신뢰성 향상을 위해 RCPC codes와 Hybrid-ARQ type-2 전송 방식을 사용한 협업 통신 시스템을 제안하고 그에 대한 시뮬레이션을 실시하였다. 그 결과로 기존의 전송에 비해 제안한 시스템이 낮은 BER값을 가져옴을 보였다. 또한 릴레이 노드와 목적지 노드 사이의 채널 상태보다 소스 노드와 릴레이 노드 사이의 채널 상태가 시스템 성능에 더 중요하다는 사실을 확인하였다.

• 한국정보통신학회논문지
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• 제25권9호
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• pp.1220-1226
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• 2021

본 논문에서는 기지국의 역할을 수행하는 드론을 기반으로 하는 무선 통신 시스템에서 주파수 효율 성능 향상을 위한 확률적 핸드오버 기법을 제안한다. 제안하는 기법은 이동하는 드론 기지국이 지상에 위치한 사용자 단말에게 서비스를 제공하는 무선 네트워크 환경에서 드론 기지국과 사용자 단말 간 거리 및 소규모 페이딩을 고려하여 드론기지국들 간의 핸드오버를 수행한다. 또한, 제안하는 기법은 빈번한 핸드오버 수행 시 발생할 수 있는 시그널링 오버헤드를 완화하기 위해 드론 기지국들 간 핸드오버를 수행할 확률을 고려한다. 드론 기반 무선 통신 시스템에서의 시뮬레이션을 통해 제안하는 핸드오버 기법 및 기존 핸드오버 기법의 주파수 효율 성능 및 핸드오버 확률을 평가한다. 시뮬레이션 결과를 통해 드론 기지국과 사용자 단말 간의 거리만을 고려한 기존의 핸드오버 기법보다 제안하는 핸드오버 기법에서 더 높은 평균 주파수 효율 성능이 나타남을 보인다.

• 기술사
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• 제44권5호
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• pp.42-47
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• 2011

Currently, wireless communication environment in high-rise buildings are limited in the basement and ground floor facilities are not in common use do not part, in case of disaster is difficult for efficient repression. In this paper, wireless communication facilities on the ground floor of the skyscraper by building infrastructure, wireless communications is proposed to eliminate shadows. That the presence of various wireless communication systems, wireless communication system proposed by this paper, TPS laying coaxial cable seals leak, and the propagation shades in place by installing indoor antenna is the solution to eliminate shadows. The wireless communications solutions reveal the advantages and features, a method of constructing the proposed design.