• Title, Summary, Keyword: WiFi

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Channel Characteristic and Link Quality Assessment of ZigBee Under Wi-Fi Interference (Wi-Fi 간섭 환경에서 ZigBee 소자의 채널 특성 및 링크 품질 평가)

  • Ahn, Seong-Beom;Kim, Hyeon-Ho;Choi, Sang-Jin;Rho, Do-Hwan;Pan, Jae-Kyung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5479-5486
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    • 2012
  • In this paper, we have measured PRR, RSSI and LQI of ZigBee channels under Wi-Fi environment and have assessed channel characteristic and link quality. To confirm any relationship among RSSI, LQI values and PRR under Wi-Fi interference in overlapping and non-overlapping channels of Wi-Fi and ZigBee, the experiments were performed without Wi-Fi, with Wi-Fi and file download through Wi-Fi. Under Wi-Fi interference, We perfomed experiments to ensure channel characteristics and link quality by fixing Wi-Fi and ZigBee receiver and varying the distance between ZigBee receiver and transmitter. ZigBee transmitter sends packet of 256 bits every second to ZigBee receiver. PRR was measured from ZigBee with variance of distance between fixed Wi-Fi and ZigBee. RSSI, LQI, PRR were measured from ZigBee with fixed Wi-Fi, fixed ZigBee receiver and variance of distance of ZigBee transmitter. As a result, we confirmed decrease of PRR under Wi-Fi interference but RSSI, LQI values similar regardless of overlapped or non-overlapped channel and Wi-Fi interference. Therefore, PRR should be used for interference detection in ZigBee communication under Wi-Fi environment but RSSI and LQI are not appreciate.

A Study on the Channel Handover Method for Super Wi-Fi Service Continuity in TV White Spaces (Super Wi-Fi 환경에서 서비스 연속성을 위한 끊김없는 채널이동 방안 연구)

  • Kim, Myeongyu;Jeon, Youchan;Park, Sangwon;Park, Jinwoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37B no.11
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    • pp.1050-1057
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    • 2012
  • Super Wi-Fi is a newly emerging wireless Internet technology, which constitutes Wi-Fi networks using TV white space. A key technical challenge in the Super Wi-Fi applications is how to provide a seamless Internet service even when a Super WiFi user should give up the channel in use to the active incumbent user which is activated in the same service area, preventing from the service continuity in Super Wi-Fi. In this paper, we propose a channel handover method to support service continuity of Super Wi-Fi, in which an AP selects a new operational channel and provides the channel information for MSs. Therefore, the AP and the MSs can carry out seamless handover for Super Wi-Fi service. A performance evaluation shows that the proposed scheme is superior to the conventional Wi-Fi in channel mobility delay.

Implementation of WiFi-to-WiBro Access Point -WiMAX CPE (WiFi-to-WiBro Access Point 구현 -WiMAX CPE)

  • Park, Chun-Kwan;Song, Han-Young;Jeon, Byung-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.9 no.5
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    • pp.53-63
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    • 2009
  • This paper is to develop WiMAX CPE(wireless AP) that can provides Wi-Fi terminal with wireless Internet service by connecting to Wibro wireless network. This AP aims to support WiBro in upstream interface basically, and Wi-Fi and 100M Ethernet interface in downstream. So, we has developed the equipment for business that wireless ISP can provide many Internet customers with wireless Internet service by using Wi-Fi terminal in subway, car, ship, and so on, and the equipment for users that a user can purchase and then install in person. For the latter, multiple Wi-Fi terminals that be registered in WiBro service can be connected to Internet simultaneously.

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Implementation of HSDPA-to-WiFi Access Point -HSDPA CPE (HSDPA-to-WiFi Access Point 구현 -HSDPA CPE)

  • Park, Chun-Kwan
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.5
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    • pp.167-172
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    • 2010
  • This paper is to implement HSDPA-CPE that can provides WiFi terminal with wireless Internet service through the connection to HSDPA wireless network. This system aims to support HSDPA interface in upstream, and WiFi and 100Mbps Ethernet interface in downstream. So, this system can provide multiple Internet customers with wireless Internet service by using WiFi terminal in subway, car, ship, and so on, and WiFi terminals that be registered in HSDPA service can be connected to Internet.

Implementation of Bistatic Backscatter Wireless Communication System Using Ambient Wi-Fi Signals

  • Kim, Young-Han;Ahn, Hyun-Seok;Yoon, Changseok;Lim, Yongseok;Lim, Seung-ok;Yoon, Myung-Hyun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.2
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    • pp.1250-1264
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    • 2017
  • This paper presents the architecture design, implement, experimental validation of a bistatic backscatter wireless communication system in Wi-Fi network. The operating principle is to communicate a tag's data by detecting the power level of the power modulated Wi-Fi packets to be reflected or absorbed by backscatter tag, in interconnecting with Wi-Fi device and Wi-Fi AP. This system is able to provide the identification and sensor data of tag on the internet connectivity without requiring extra device for reading data, because this uses an existing Wi-Fi AP infrastructure. The backscatter tag consists of Wi-Fi energy harvesting part and a backscatter transmitter/a power-detecting receiver part. This tag can operate by harvesting and generating energy from Wi-Fi signal power. Wi-Fi device decodes information of the tag data by recognizing the power level of the backscattered Wi-Fi packets. Wi-Fi device receives the backscattered Wi-Fi packets and generates the tag's data pattern in the time-series of channel state information (CSI) values. We believe that this system can be achieved wireless connectivity for ultra- low-power IoT and wearable device.

Design and Implementation of a WiFi Trashcan based on Arduino (아두이노 기반 WiT(WiFi Trashcan)의 설계 및 구현)

  • Yoo, Jong-Yeol;Kim, Hyun-Il;Lee, Jang-Ho;Yang, Dong-Min
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.270-273
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    • 2016
  • Recently due to development of IT technology, ideas and technology that blends with environment has evolved. In this paper, we propose WiT(WiFI Trash-Can) which takes advantage of the IT technology fusion and environmental factors at the same time to create a more pleasant environment. WiT provides a free WiFi when disposing trash in the trash can. WiT which is synthetic name for WiFi and Trash-Can is a system that is provides free WiFi when people dispose litter to detect whether user had access and determined the volume of the trash disposed. WiT uses Arduino and Raspberry Pi to detect the amount of trash and provide WiFi output on the display to show the ability to design and implement the remaining amount of time available.

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Design and Implementation of a WiFi Trashcan based on Arduino (아두이노 기반 WiT(WiFi Trashcan)의 설계 및 구현)

  • Yoo, Jong-Yeol;Kim, Hyun-Il;Lee, Jang-Ho;Yang, Dong-Min
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.11
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    • pp.2143-2148
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    • 2016
  • Recently due to development of IT technology, ideas and technology that blend with environment have evolved. This technology can help people's living environment and in the future it is an essential component of the connected society. In this paper, we propose WiT(WiFI Trashcan) which takes advantage of the IT technology fusion and environmental factors at the same time to create a more pleasant environment. WiT provides a free WiFi when trash is disposed in the trash can. WiT detects whether a user disposes trash, determines the volume of the trash and provides free WiFi. To detect trash we use ultrasonic sensor and trash weight is measured by using weight sensor. Also by using Phython programming the measured sensor value is transmitted to Raspberry Pie and WiFi delivery time is determined. We used Arduino and Raspberry Pi to design and implement WiT.

Handover Scheme between WiFi and Mobile WiMax (WiFi와 mobile WiMax간 핸드오버 방안)

  • Park, Seung-Kyun
    • The Journal of the Korea Contents Association
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    • v.11 no.1
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    • pp.34-41
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    • 2011
  • At present wireless internet access service is available through the 3G network, mobile WiMAX and WiFi anytime and anywhere. In this environment where there are various networks, users should be able to select specific networks depending on different situations. And it is necessary to provide mobility support between homogeneous and between heterogenous networks. Given this situation, the many proposals have been presented to link 3G, which has the largest service area among various networks, with mobile WiMAX(IEEE 802.16e), or with WiFi(IEEE 802.11). But, recently, with the increasing volume of wireless internet use and wireless internet data, due to the advents of net-book, e-book and smart phone, the service area of WiFi and mobile WiMAX has rapidly expanded. Especially, the availability of real-time application such as internet phone has led to the relative shrinking of the proportion of 3G mobile communication network giving conventional voice service, and enlargement of those of wireless internet access networks like WiFi and mobile WiMAX. This paper suggests a handover scheme based on PMIPv6, whitch support mobility between WiFi and mobile WiMAX, and minimizes handover delay. In this scheme, the mobile node has a dual stack structure composed of two interfaces-WiFi and mobile WiMAX. Since WiFi dose not support mobility, it is suggested that the mobile node have the capacity to deal with handover signaling between gateway in case of handover between homogeneous networks. This handover scheme, suggested comparing with current handovers between homogeneous networks, has proved, in its analytic evaluation, to be able to reduce handover, transmission, and signaling overhead.

A Study on the Security Regulatory Issues in WiFi Network (WiFi의 보안문제와 개선방안 연구)

  • Kim, Sung Chul;MIn, Dae Hong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.678-681
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    • 2009
  • WiFi는 무선인터넷 접속(Wireless LAN) 방식의 하나로서 이동성, 설치용이성, 유연성 등으로 인하여 널리 사용되고 있다. 더욱이 기존 다양한 디지털 기기들이 WiFi 기반의 application을 탑재하여 각종 온라인 콘텐츠를 이용할 수 있게 하면서 점차 보편적인 인터넷 접속수단으로서 변모하고 있는 상황이다. WiFi의 편리성으로 인하여 기업, 공공기관, 교육기관 등에서 네트워크 구축에 WiFi를 사용하는데 그 추세가 개인부문에서 기업부문으로 확산되고 있다. 하지만 유선인터넷이 케이블이라는 매체를 통해 연결되어 외부와 차폐된데 비해 WiFi는 주파수를 매개로하기 때문에 네트워크 접근이 용이하며 이로인해 보안이 취약해 질 수 있다는 것이다. 이로 인하여 일명 워드라이빙(war driving)이라 불리는 서비스의 무단사용뿐만 아니라 악의를 가진 네트워크 침입이 가능해져 개인정보나 사유재산이 침해 가능성이 높다고 할 수 있다. 이에 본 연구에서는 해외의 WiFi의 보안관련 법제도를 살펴보고 이로부터 국내 WiFi보안을 위한 대안을 제시하고자 한다.

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Understanding Wi-Fi P2P Technical Specification (Wi-Fi P2P 기술 분석)

  • Ma, J.S.;Lee, J.H.
    • Electronics and Telecommunications Trends
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    • v.26 no.5
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    • pp.74-82
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    • 2011
  • 최근 Wi-Fi Alliance는 Wi-Fi 기반의 Peer-to-Peer(P2P) 규격인 Wi-Fi Direct 기술의 발표와 함께 인증을 진행하고 있다. Wi-Fi Direct 기술은 TV, 노트북, 프린터, 카메라와 같은 휴대기기 및 모바일 단말 등에 탑재되어 Access Point(AP) 또는 라우터와 같은 별도의 장비 없이도 단말 간 직접 통신을 통하여 기기 간 콘텐츠 및 서비스를 사용할 수 있는 기반을 제공하는 기술이다. Wi-Fi Direct 기술은 빠른 전송속도와 전송거리를 제공함으로써 향후 일부 영역에서 블루투스 기술을 대체할 수 있을 것으로 기대된다. 또한 향후 Wi-Fi Direct 규격의 전체 기능을 구현한 스마트폰이 출시된다면 사용자 경험(UX)을 극대화 시킬 수 있는 혁신적인 모바일 서비스를 제공할 수 있을 것으로 기대된다. 본 고에서는 Wi-Fi Direct의 업계 동향과 Wi-Fi Direct의 동작 원리를 표준 기술 규격서를 통해 분석하여 요약 정리한다.

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