• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1027-1034
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• 2005

IEEE802.15.4a, which is started to realize the PHY layer including high precision ranging/positioning and low data rate communication functions, requires a simple and low power consumable transceiver architecture. To satisfy this requirements, the simple noncoherent on-off keying (OOK) UWB transceiver with the parallel energy window banks (PEWB) giving high precision signal processing interface is proposed. The flexibility of the proposed system in multipath fading channel environments is acquired with the pulse and bit repetition method. To analyze the bit error rate (BER) performance of this proposed system, a noise model in receiver is derived with commonly used random variable distribution, chi-square. BER of $10^{-5}$ under the line-of-sight (LOS) residential channel is achieved with the integration time of 32 ns and signal to noise ratio (SNR) of 15.3 dB. For the non-line-of-sight (NLOS) outdoor channel, the integration time of 72 ns and SNR of 16.2 dB are needed. The integrated energy to total received energy (IRR) for the best BER performance is about $86\%$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.504-507
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• 2005

차세데 홈네트워크 환경하에서는 다양한 데이터 통신 무선기기들이 홈/오피스에서 공존할 것이다. 예를들어 무선랜, 블루투스(Bluetooth), 지그비(Zigbee), 무선 USB, UWB(Ultra Wideband) 등이 함께 주파수를 공유하게 될 것이며, 특히 ISM 대역은 서비스, 산업, 의료용 등으로 다양한 응용이 가느하기 때문에 전파 간섭이 예상된다. 본 논문에서는 IEEE 802.11b 무선랜(WLAN)과 IEEE 802.15.4 저전력 저속 무선팬(WPAN) 무선기기에 대하여 간섭실험을 하였으며 두 무선기기가 상호 공존할 수 있는 공유 조건에 대해 분석하였다. 무선랜(WLAN)과 무선팬(WPAN)의 주파수 대역이 완전히 오버랩된 경우 간섭 레벨과 무선팬의 패킷 전송 횟수를 변화 시켜 상호간의 간섭 영향 저도를 측정하고 상호 무선기기간의 간섭 결과를 바탕으로 상호 무선기기간의 주파수 공유 조건을 제시하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2021-2026
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• 2007

In the parer, we design a non-coherent UWB system by adopting the architecture of a simplified asynchronous transmission and the edge-triggered pulse transmission, which makes e system performance independent of the share of the transmitted waveform, robust to multipath channels. The designed non-coherent UWB transceiver architecture has an advantage of the simple realization since any mixer, high-speed correlator, and high-sampling A/D converter are not necessary at the cost of performance degradation of about 3dB. Further, the designed non-coherent UWB transceiver is actually implemented with the wireless CANVAS prototype testbed in short range indoor application environments such as a lecture room. The implemented prototype testbed is proven to offer the data rate of 115kbps on the conditions of Peer-to-Peer(P-to-P) in the indoor channel within the range of about 10m.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.688-695
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• 2014

In a small wireless environment, such as your home or office, a various network using WiMedia PHY can be mixed. Because these networks operate independently for each application, data conflict can occur between adjacent networks. To avoid data conflict, the resource in a different time zone can be utilized. However, if devices in a network increase, available resources in the network decrease, and then the lack of resources necessary to provide service can occur. To solve this problem, we propose collision avoidacne scheme for coexistence of various UWB systems. In this paper, we evaluate the performance of the proposed scheme through simulation.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1163-1166
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• 2009

전 세계적으로 유헬스 서비스에 대한 관심도가 증가함에 따라 유헬스의 핵심기술 가운데 하나인 무선통신기반의 생체신호 전송기술에 대한 연구 또한 활발히 진행되고 있다. 특히 2000년대부터 시작하여 이미 많은 연구가 진행되어 온 WPAN에서는 Zigbee, Bluetooth, UWB 등의 무선대역을 통하여 생체 신호를 전송하는 연구가 상당히 진행되어 왔으며, 최근에는 IEEE 802.15.6 WBAN에서 MICS, WMTS등과 같은 무선대역을 이용하여 생체신호를 전송하기 위한 연구를 새로이 진행하고 있다. 특히 WLAN이 무선통신기술에 있어 1세대라 하고, WPAN이 2세대라 한다면 WBAN은 3세대 무선통신기술이라고 할 만큼 새로운 시장을 형성할 것으로 예상된다. 따라서 본 고에서는 기존의 WPAN과 최근에 이슈가 되고 있는 WBAN의 무선기술을 통해 생체신호를 전송하기 위한 기술을 분석하고 향후 연구해야 할 내용에 대해 언급하기로 한다.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.53-59
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• 2007

Wimedia UWB(Ultra-Wideband) platform provides data rates up to 480Mbps in WPAN (Wireless Personal Area Network). Wimedia conformant devices access to the channels through superframe concept for communications. As the channel resource is limited, the optimal channel time required for each device needs to be estimated to share the resource efficiently among the devices. In this paper, we propose a scheme to estimate the required channel time in a super frame to satisfy the QoS of the application on a device. The channel time is estimated from the service rate which is computed from the TSPEC of the application. In the process of the estimation, we take the frame overhead for data transmission as well as the overhead due to the acknowledgement scheme, preamble, and MDSU size into consideration. We also analyze and compare the throughputs for different acknowledgement scheme, preamble, and MDSU size situations. The estimated channel time required for a given service rate is allocated in the unit of MAS(Medium Access Slot).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.53-65
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• 2012

Recently wireless intra-vehicle communication has received a great interest from the automotive industry and ultra wideband (UWB) technology is considered as one of the potential candidate for this system. Many research works have been done on the measurement and modeling of intra-vehicle communication channel. However, very little work has been reported for the performance analysis of various PHY layer methods under the intra-vehicle communication environment. This paper is to study IEEE 802.15.4a standard in intra-vehicle channel and to evaluate its performance. Channel model in chassis and engine compartment is considered for evaluation. Through simulation BER performance of system with different receiver structures is analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1324-1329
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• 2013

The WiMedia Alliance has specified a Distributed Medium Access Control (D-MAC) protocol based on UWB for high speed wireless home networks and WPANs. In this paper, firstly, the fair SoQ-based Distributed Reservation Protocol (DRP) for D-MAC is analyzed. And a novel SoQ-based relay transmission protocol is proposed to overcome DRP conflicts fast. In the proposed protocol, each device executes the Satisfaction of QoS (SoQ) time slot allocation algorithm independently. And, in order to give the loser device due to DRP conflicts another chance to maintain QoS resources, the proposed relay transmission protocol helps the device reserve another indirect link maintaining the required QoS resources via a relay node.

• Journal of Communications and Networks
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• v.11 no.4
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• pp.375-383
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• 2009

The WiMedia alliance has specified a distributed medium access control (WiMedia MAC) protocol based on ultra wideband (UWB) for high data rate WPANs (HR-WPANs). The merits of WiMedia MAC such as distributed nature and high data rate make it a favorite candidate in HR-WPAN. Although QoS parameters such as the range of service rates are provided to a traffic stream, the WiMedia MAC is not able to use the QoS parameters and to determine or adjust a service rate using the QoS parameters for the traffic stream. In this paper, we propose a fair and adaptive resource allocation method that allocates time slots to isochronous streams according to QoS parameters and the current traffic load condition in a fully distributed manner. Although the traffic load condition changes, each device independently recognizes the changes and calculates fair and maximum allowable service rates for traffic streams. From the numerical and simulation results, it is proved that the proposed method achieves high capacity of traffic streams and fair QoS provisioning under various traffic load condition.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.659-661
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• 2011

최근 WPAN 분야의 솔루션인 IEEE 802.15.4a는 저소비 전력으로 통신과 거리측정을 동시에 가능케 하는 PHY 제정을 목표로 하고 있다. 본 논문은 IEEE802.15.4a 물리계층에서 사용하는 UWB 신호를 대상으로 거리인식 시스템을 위한 Link Budget을 분석한다. 거리인식 시스템의 성능은 무선 채널의 다중경로 프로파일에도 관계된다. 따라서 본 연구에서는 IEEE 802.15.4a 채널 특성인 Residential 및 Office 환경을 고려하여 거리인식 시스템을 위한 Link Budget을 분석하였으며 연구된 내용은 다양한 거리추정 방식에 적용하여 거리추정 정밀도 향상에 기여할 수 있을 것이다.