• 한국정보통신학회논문지
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• 제8권6호
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• pp.1055-1059
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• 2004

RFID(Radio frequency Identification)시스템은 일종의 무선통신 시스템으로서 자동화 데이터 수집장치의 한 분야에 속한다. 이 무선 시스템은 RFID 태그(혹은 트랜스폰더 Transponder)와 RFID 리더로 구성되어 있다. 본 논문에서는, RFID 시스템으로부터 태그 ID를 획득하여 무선LAN으로 인터넷에 접속한 후, 태그 ID정보를 처리하기 위하여 웹상의 서버로 전송하거나 자체 웹서버를 가지는 타깃시스템을 구현한다. 기존의 시스템들은 정보획득 후 유선으로 태그 데이터를 전송하는 형태가 주를 이루고 있으나 본 시스템은 현재 사용이 확산되고 있는 무선 LAN을 이용하여 AP(Access Point)가 있는 장소이면 어디에서나 인터넷에 접속하여 유비쿼터스 환경에서 수집된 다양한 데이터를 쉽게 전송할 수 있게 한다. 또한 무선LAN의 광대역 이점을 이용하여 대용량의 정보를 타깃시스템에 전송할 수 있으며 인가된 사용자가 타깃시스템의 웹서버에 용이하게 접속하여 각 태그 ID를 분석하고 그에 대한 각종 정보를 다양하게 획득할 수 있도록 구현된다.

• 대한전자공학회논문지TE
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• 제37권1호
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• pp.50-57
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• 2000

무선 통신 기술의 발전으로 기존 유선 전화 선로를 무선으로 대체하고자 하는 무선 가입자망 (WLL) 의 상용화가 가속화되고 있다. WLL(Wireless Local Loop) 기술을 적용함으로써 사업자는 유선 선로에 비해 설치 및 유지 보수등의 이점을 얻게 되고, 가입자는 전화 서비스외에 고속의 부가 서비스를 제공받을 수 있는 장점등의 이유로 많은 통신 업체와 사업자들의 큰 관심과 함께 개발과 적용이 늘고 있다. 본 논문에서는 WLL 시스템 구성중 기지국 제어기 시스템의 하드웨어(Hardware) 구현에 관한 것으로, 기지국 제어기의 시스템 하드웨어 구성과 기능 및 시스템 IPC(Inter Processor Communication) 구조등의 개발 내용을 기술하였다. 그리고 개발 시스템 검증은 IPC Backplane 버스를 통한 모듈간 통신 시험에 의해서 수행하였다. 모듈간의 반복적인 데이터 통신시험과 동시에 신호파형 측정으로 기본적인 시스템 통합시험을 완료하였다.

• ETRI Journal
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• 제41권2호
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• pp.224-234
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• 2019

This paper proposes a new spectrum forecasting (SF) model to estimate the spectrum demands for future mobile broadband (MBB) services. The model requires five main input metrics, that is, the current available spectrum, site number growth, mobile data traffic growth, average network utilization, and spectrum efficiency growth. Using the proposed SF model, the future MBB spectrum demand for Malaysia in 2020 is forecasted based on the input market data of four major mobile telecommunication operators represented by A-D, which account for approximately 95% of the local mobile market share. Statistical data to generate the five input metrics were obtained from prominent agencies, such as the Malaysian Communications and Multimedia Commission, OpenSignal, Analysys Mason, GSMA, and Huawei. Our forecasting results indicate that by 2020, Malaysia would require approximately 307 MHz of additional spectrum to fulfill the enormous increase in mobile broadband data demands.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권5호
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• pp.998-1013
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• 2013

Wireless wearable sensor networks have emerged as a promising technique for human motion tracking due to the flexibility and scalability. In such system several wireless sensor nodes being attached to human limb construct a wearable sensor network, where each sensor node including MEMS sensors (such as 3-axis accelerometer, 3-axis magnetometer and 3-axis gyroscope) monitors the limb orientation and transmits these information to the base station for reconstruction via low-power wireless communication technique. Due to the energy constraint, the high fidelity requirement for real time rendering of human motion and tiny operating system embedded in each sensor node adds more challenges for the system implementation. In this paper, we discuss such challenges and experiences in detail during the implementation of such system with wireless wearable sensor network which includes COTS wireless sensor nodes (Imote 2) and uses TinyOS 1.x in each sensor node. Since our system uses the COTS sensor nodes and popular tiny operating system, it might be helpful for further exploration in such field.

• 한국인터넷방송통신학회논문지
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• 제9권6호
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• pp.195-200
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• 2009

본 논문에서는 지방상수도에서 운영되고 있는 유선망을 무선랜방식의 Wi-Fi망으로 시범도입 하였고 현장 실증시험을 통해 신뢰성을 검증하였다. 도입된 무선통신망은 기존 유선통신망에 비해서 비용절감 및 고장점 감소를 통해 정성적 및 정량적으로 효과가 있음이 알 수 있었다. 이번 연구로 기존의 광역상수도와 현재 위 수탁 운영 중인 지방상수도 운영관리의 고도화를 위해 무선통신망이 도입 가능함을 입증할 수 있었다.

• 한국구조물진단유지관리공학회 논문집
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• 제3권4호
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• pp.199-204
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• 1999

The continuing development of the sensors for the measurement of the safety of structures has been making a turning point in measuring and evaluating the larger civil structural system as well. However, there are still remaining problems to be solved for the extremely large structure because the natural damages of those structures are not so simple to be monitored for the reason of their locational and structural conditions. One of the most significant problems is that a number of cables which connect the measuring system to the analyzer are liable to distort actual data. This paper presents a new monitoring system for large structures by means of a local wireless communication technique which would eliminate the possibility of the distortion of data by noise in cables. This new monitoring system employs the wireless system and the software for data communication, along with the strain sensor and accelerometers which have been already used in the past. It makes it possible for the data, which have been chosen by the central controling system from the various sensors placed in the large civil structures, to be wirelessly delivered and then analyzed and evaluated by decision making system of the structures.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제22권8호
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• pp.381-386
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• 2016

최근 자기간섭제거 기술의 발전으로 무선 네트워크에서 전이중통신이 가능하게 되었다. 전이중통신은 같은 채널에서 동시에 송/수신을 할 수 있기 때문에 차세대 무선통신기술로 주목 받고 있다. 기존 MAC(Medium Access Control) 프로토콜들은 반이중통신을 기반으로 설계되었기 때문에 전이중통신에 적합하지 않다. 따라서 본 논문에서는 전이중 MAC 프로토콜을 설계할 때 고려해야 될 사항에 대해 논의하고, 이를 바탕으로 새로운 전이중 MAC 프로토콜을 제안한다. 시뮬레이션 결과를 통해 제안된 MAC 프로토콜과 기본 전이중통신을 비교하여 성능향상을 확인한다.

• 통합자연과학논문집
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• 제10권4호
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• pp.216-224
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• 2017

In the terrain of the Korean peninsula, mountainous and flat lands are complexly distributed in small areas. Therefore, local severe weather develops and disappears in a short time due to the influence of the terrain. Particularly in the case of local severe weather with heavy wind that has the greatest influence on aviation meteorology, the scale is very small, and it occurs and disappears in a short time, so it is impossible to predict with fragmentary data alone. So, we use weather radar to detect and predict local severe weather. However, due to the development of wireless communication services and the rapid increase of wireless devices, radio wave jamming and interference problems occur. In this research, we confirmed through the cases that when the radio interference echo which is one of the non-precipitation echoes that occur during the operation of the weather radar is displayed in the image, its form and shape are shown in a long bar shape, and have a strong dBZ. We also found the cause of the interference through the radio tracking process, and solved through the frequency channel negotiation and AP output minimizing. The more wireless devices increase as information communication technology develops in the future, the more emphasized the problem of radio wave interference will be, and we must make the radio interference eliminated through the development of the radio interference cancellation algorithm.

• Current Optics and Photonics
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• 제2권4호
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• pp.308-314
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• 2018

Visible light communication (VLC) is considered a strong future candidate for indoor wireless communication. However, its performance seems to be relatively unsatisfactory when compared to wireless local area network (WLAN) communication using millimeter waves. To improve the performance of VLC, numerous technologies have been proposed so far, in both electrical and optical domains. Among the proposals, optical beamforming (OB) is an optical-domain technology that can concentrate light in a specific direction or on a target spot. It can significantly improve VLC performance and can be widely used, because it does not depend on electrical modulation schemes. Therefore, this review discusses the concept, principle, and types of OB, the structure of a VLC system using OB, performance results of OB, and the combination of OB with electrical signal modulation in VLC. OB is expected to be one of the key techniques in future VLC implementations, similar to radio-frequency beamforming in millimeter-wave communication.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2005년도 제4회 추계학술대회 및 정기총회
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• pp.83-88
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• 2005

A transportation problem in Korea is a serious issue that has to be solved urgently in the motor era of 15 million vehicles. Recently ITS has been introduced to improve efficiency of the current roads because an excessive budget and a long term construction are needed to build new roads. Therefore the government enacted the law as of ITS and the in architecture. However, these ITS information services were oriented to mainly vehicles and drivers, not public entities such as bus driver, passengers and so on. Nowadays lots of local autonomous city introduced a public transportation information system (PTIS), and providing useful information for the public. For this PTIS, important design issues are to be focused on detecting and tracking technology of moving bus, and a wireless communication link to transmit the location information. This paper presents design models using several wireless communication methods, and an implementation case using a Wireless packet Data communication Network (WDN) to transmit bus location information at Seoul, Korea.