• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.261-268
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• 2014

This paper presents a electrocardiogram(ECG), electromyogram(EMG), and Photoplethysmography(PPG) signal wireless monitoring system based on Bluetooth Low Energy (BLE). ECG and EMG sensor interface analog front-end circuits are designed by using off-the-shelf parts. Texas Instruments(TI)'s CC2540DK is used for BLE-based communication. Two CC2540DK modules are used as Peripheral and Central nodes. In peripheral device, vital signals are acquired by the analog front-ends and fed to ADC for analog-to-digital conversion. The peripheral transmitts the data through the air to the central device. The central device receive the data and sends them to PC using UART. GUI is designed using Labview for displaying the acquired vital signals. The developed system can be used for future ubiquitous wireless healthcare system based on bluetooth 4.0.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.132-135
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• 2002

In radio communication technology, SDR(Software Defined Radio) technology is emerging as a trendy technology for future. SDR is expected to change existing radio systems including central hardware. SDR is equipment that wireless parameters (frequency, modulation, additional service, power level, receive sensitivity, etc.) are controlled by software. In the world, equipments using the new technology are spreading. Not only equipments being imported but also local manufacturers are making this equipment, developing software and offering upgraded service. In the future, as SDR spreads and users choose the service, diverse equipments will be developed through competition and individual development. This diversity of equipment and services will introduce problems in compatibility and interoperation issues. So the government will have to make technical standard for SDR service and will have to make theses standards available to users and manufacturers alike. Therefore I am investigating the elements that can be used to establish these standards.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.858-861
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• 2011

In this paper, we present a RFID system by using a wireless sensor network. The proposed system is installed in glove for activity monitoring. The RFID reader, to send data by using sensor network platform and RFID tag are small size, the shape of quadrangle, and operate in the frequency of 13.56 MHz. The sensor node can read RFID tags on the various objects used in daily living such as furniture, medicines, and kitchenwares. The sensor node reads the data of RFID tags, it transmits wireless packets to the sink node. The sink node sends the received packet immediately to a server system. The data from each RFID system is collected into a database, and then the data are processed to visualize the measurement of daily living activities of users. We provide a web-based monitoring system, and can see the number of RFID tag readings per day as bar charts. The result of experiments demonstrates that the way we propose can help to check the situation of life for people who live alone.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.367-373
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• 2022

VANET (Vehicular Ad hoc NETwork) is one of the special cases of the ad hoc networks in which car nodes communicate with each other and/or with RSUs (Road Side Unit) in order for the drivers to receive nearby road traffic information as well as for the passengers to retrieve nearby gas price or hotel information. In case of constructing VANET over CCN, users do not need to specify a destination server address rather to input a key word such as nearby congestion in order to gather surrounding traffic congestion information. Furthermore, each car node caches its retrieved data for forwarding other nodes when requested. In addition, the data transmission is inherently multicast, which implies fast data propagation to the participating car nodes. This paper measures and evaluates the data transmission performance of the VCCN (VANET over CCN) in which nodes are equipped with diverse wireless communication channels. The simulation result indicates that 802.11a shows the best performance of the data transmission against other wireless channels. Moreover, it indicates that VCCN improves overall data transmission and provides benefit to the nodes that request the same traffic information by exploiting inherent multicast communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.356-368
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• 2011

While most of the public radio spectrum bands are allocated to licensed users, cognitive radio has been considered as a promising technology for the efficient spectrum utilization. In this new technology, secondary users opportunistically use the temporally underutilized licensed bands as long as they do not give the harmful interference to primary users. In this paper, we focus on the infra-structured network condition in which the cognitive radio network consists of a cognitive radio base station and multiple secondary users. Upon detecting a primary user, the entire cognitive radio network generally switches to another available channel, even if most of the on-going communications still does not interfere with the primary user. Moreover, the network re-entry process on a new channel causes the service disruption of the on-going communications. For this reason, in this paper, we propose a relaying scheme for efficient frequency usage, in which the secondary user out of the interference range of a primary user performs as a relaying node for the secondary user possibly interfering with a primary user. The entire spectrum switching is not required, and thus, we can avoid the service disruption of the on-going communications as much as possible.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.1-5
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• 2011

For measuring quad-band module system using WiBro network, frequency converter was developed. The size of the fabricated frequency converter is $3.1cm{\times}3.1cm{\times}0.4cm$. Noise figure of the receiver part of the frequency converter was 2.62 ~ 3.45 dB, EVM of that is -37.5 dB ~ -34.5 dB. And EVM of the transmission part was -42.5 ~ -35.5 dB. Quad-band module was fabricated with the developed frequency converter. Testing the quad-band module in 2.3 GHz WiBro network results the excellent internet connection for 2.5 GHz, 3.5 GHz and 5.5 GHz band.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11A
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• pp.876-882
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• 2003

The future wireless communication systems will use spatial multiplexing with Multiple Input Multiple Output(MIMO) system to take advantage of large channel capacity gains. In such systems it will be desirable to select a sub-set of available transmit or receive antennas to reduce cost and complexity. In this paper we propose a novel antenna selection schemes for MIMO systems be suitable for multipath environment. Also, we analyze the capacity and define the outage probability for a novel antenna selection schemes for MIMO systems in multipath environment.

• Journal of Korea Spatial Information System Society
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• v.5 no.1 s.9
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• pp.75-81
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• 2003

In spite of widely deploying information broadcasting services based on Internet, there are some limitations to use them due to the bound of Internet protocol. In this paper, a new Internet broadcasting technology for access network and Location Based Services are proposed by employing IP address translation function in base station. There are some advantages such as, no need to allocate IP address to receiver no need to know web site address, and reduction of traffic for server and network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.398-402
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• 1998

본 논문에서는 유ㆍ무선 통신 채널을 통한 데이터 전송시 발생하는 비선형 왜곡을 적응 필터를 이용하여 보상하였다. 특히 통신채널에서는 심볼간 간섭(ISI)이 발생하는데 이러한 간섭을 비선형 필터를 이용하여 제거하였다. 비선형 채널을 모델링하는 방법에는 볼테라급수를 이용하는 방법과 쌍선형 방법이 있다. 쌍선형 방법은 볼테라 방법에 비하여 계산량이 적은 장점을 지니고 있다. 따라서 쌍선형 필터에 적응 알고리듬을 적용하여 신호의 왜곡을 보상하였다. 적응 알고리듬에는 LMS 계열과 LS 계열 알고리듬이 있으나 통신 채널에서는 알고리듬의 안정도가 중요하므로 LMS 계열 알고리듬을 적용하였다. 또한 적응 알고리듬은 입력 데이터의 상관성과 데이터 수에 의존하여 수렴속도와 안정도가 결정된다. 알고리듬의 수렴속도를 증가시키기 위하여 입력신호를 신호파형으로부터 다량의 데이터를 검출하는 방법을 적용하였다. 이러한 방법을 입증하기 위하여 입력신호는 2진 랜덤 가우시안 데이터를 이용하였고, 통신채널에서 채널간 간섭을 발생시켰으며 화이트 가우시안 잡음을 부가 시켰다. 이러한 신호를 수신한 수신기에 적응 등화기를 설계하여 대량의 데이터를 생성시키고, 적응 알고리듬을 적용하여 채널의 왜곡을 빠른 속도로 보상하였다.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.247-249
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• 2002

본 PowerMeter-Modem은 시스템 서버의 전단 통신 장치부의 무선모뎀과 IS-95B 망을 통해 서킷 접속을 하며 검침수행 관련정보를 수신하여 전자식 전력량계와 RS232 시리얼통신을 이용하여 전자식 전력량계의 전력량의 데이터를 취득 후 가공하여 서킷 방식이나 TCP/IP 프로토콜을 이용 패킷형태로 검침데이타를 IS-95B 망과 시스템간 프로토콜 변환장치를 거쳐 전단 통신 처리장치로 송출하는 역할을 한다.