• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.456-458
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• 2010

VoIP services are growing fast and WLAN VoIP phones are being used in widespread. Emergency services are very critical in WLAN VoIP as in other traditional networks. This paper summarize recent standards of IEEE 802.11 supporting emergency services in WLANs. Two standards are discussed. The 11u deals with the aspect of access in WLAN emergency services, and the 11v deals with the location services.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2062-2068
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• 2008

In a u-City project in Busan, public transportation which is one of ITS has been considered. RFID system embedded with PXA255 chip and middleware capable of communicating a server side was developed. To perform data communication link with traffic card, developed system consists of wireless modules that are wireless LAN (IEEE802.11a/b and IEEE802.16. Using developed RFID system and middleware, it is expected that this system becomes a basic infrastructure to support a service of u-Traffic for u-City construction.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1066-1070
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• 2010

In wireless network, energy efficiency is an important design consideration for continuous multimedia streaming service. This paper proposes a new streaming system, called BACASS (Buffer-Aware and Content-Aware Streaming System) that working on the 802.11e U-APSD (Unscheduled Automatic Power Save). The BACASS leads the DP (Doze Period) of U-APSD for improving energy efficiency by utilizing the PSNR based on content-aware and client buffer occupancy that is hinged on a network-aware streaming system using SVC. The simulation results demonstrate the effectiveness of the proposed streaming system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.117-124
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• 2009

In this paper, we have developed communication modules for ubiquitous transportation sensor network (u-TSN). The developed module can be used for intelligent transportation services. The developed systems are based on IEEE 802.11a and IEEE 802.11g technologies for vehicle and infrastructure systems, respectively. We have found that the throughput for the developed systems is at maximum around 15 Mbps. It is reduced to 10 Mbps at a long distance and high speed condition. The performance is enough to support traffic control services in dense traffic condition.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.216-217
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• 2010

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.459-462
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• 2008

By using RFID technology in order to manage public traffic management, RFID system and middleware software with PXA255 ARM chip is developed and is capable of operating the traffic card. The developed RFID system consists of 13.56MHz RFID R/W, wireless LAN (IEEE802.11.a/b), Wibro (IEEE802.16), TFT-LCD to display information, and embedded system to collect a charge information, etc. By applying developed system, basic infra-structure capable of supporting various service of u-Traffic can be effectively applied.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.416-422
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• 2006

In this paper, we have designed and favricated the high gain and wideband microstrip patch antenna including IEEE 802.11a. To widen the bandwidth of microstrip antenna, firstly we have used the microstrip line-coaxial probe feeding method and inserted a U-slot in the rectangular patch. Secondly, to improve the antenna gain, we have used a $2{\times}2$ array structure. From the measured results, wideband characteristics of 1 GHz bandwidth($5.110{\sim}6.142$ GHz) for VSWR<2 was obtained. The measured eain was 13 dBi in both the E-plane and H-plane at the frequency of 5.15 GHz, 5.35 GHz, 5.50 GHz, and 5.85 GHz.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.376-376
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• 2004

• KSCI Review
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• v.15 no.1
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• pp.225-228
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• 2007

컴퓨터 영상 화면을 아날로그 음성영상신호로 변환한 후 무선으로 송신하여 처리하기 때문에 해상도가 낮아 화질이 떨어진다. 또한 대형프로젝션TV에 보낼 영상화면의 단말기 RGB포트에 게이트웨이를 직접 연결해야 하는 불편이 따른다. 이러한 문제를 해결하기 위하여 이 논문에서는 IEEE802.11b/g 무선네트워크 기반에서 대용량 영상데이터를 최대 54Mbps의 속도로 송수신할 수 있는 무선통신시스템 개발과 이를 게이트웨이에 적용하여 영상데이터까지 무선으로 처리할 수 있도록 하는 장치를 개발하고, 대용량 영상데이터 송수신 처리 소프트웨어를 개발한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.175-181
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• 2015

In this paper, we develop a 2.4GHz ISM band wireless communication platform prototype based on embedded linux which support can be u-Hospital service. The developed system is available connecting between ARM920T processor board and FPGA board and linking IEEE 802.11b PHY board, AD/DA(10Bit) and RF(2.4GHz) board for wireless access. It is also can be utilized for the embedded system design with IEEE 802.11b/g Access Point(Option: IEEE 802.11a/b/g) test due to the Embedded Linux. Also, the developed system is possible to test and verify the radio access technology, Modem(OFDM etc) and IP(Intellectual Property) circuit. And make the most use of the system, we search for a expansion to that home and mobile healthcare, wellness service application.