• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1558-1562
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• 2005

This paper describes the design and implementation of a wireless home network system using Home Network Control Protocol (HNCP) called the wireless HNCP home network system. For wireless interfaces of HNCP, IEEE 802.11b and IEEE 802.15.4 standard protocols are considered. With the implementation of the wireless HNCP home network system, a simple analysis about coexistence between IEEE 802.11b and IEEE 802.15.4 is achieved. Through the implemented wireless HNCP home network system and the analytical results about the coexistence between both two different wireless protocols, the feasibility of the wireless HNCP home network system is shown.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.892-896
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• 2011

This paper proposes a two-stage synchronization scheme using a serial search non-coherent correlator appropriate for the IEEE 802.15.4a system. The proposed method improved the synchronization performance by using multi-pulse signals unlike the conventional method using single-pulse signals. It also compensated for the degradation of performance at low SNR resulting from the use of fixed threshold by applying the adaptive threshold technique. The proposed method showed a detection probability that is higher by approximately 0.2-0.3 compared with the conventional method in the IEEE 802.15.4a channel model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3A
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• pp.205-212
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• 2009

A novel channel estimation scheme is proposed for coherent Impulse Radio Ultra Wideband (IR-UWB) system based on IEEE 802.15.4a specification. By extracting and utilizing the information on the frequency synchronization, the proposed channel estimation algorithm improves the receiver performance even under the restricted number of preamble symbols in IEEE 802.15.4a signal format. Simulation results over the IEEE 802.15.4a channel models show the performance gain with the proposed algorithm compared to ordinary channel estimation method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.4
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• pp.26-33
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• 2012

Please WBAN(Wireless Body Area Networks) is wireless communication of within 3 m radius from inside and outside of the body. WBAN is many uses IEEE 802.15.4 MAC protocol for WBAN MAC protocol requirements. IEEE 802.15.4 MAC protocol applies GTS(Guaranteed Time Slot) allocation scheme for guarantee packet delivery of application which requests QoS(Quality of Service). However, GTS allocation scheme of IEEE 802.15.4 MAC protocol uses FIFS(First In First Service) queueing. So it reduces data transmission reliability and has many problems. Therefore, IEEE 802.15.4 applies not WBAN MAC protocol for emergency data transmission. In this paper, we proposes a priority based MAC protocol for emergency data transmission in wireless body area networks. the proposal MAC protocol sets priority the data. So GTS reqeuest throughput of emergency data increasing and GTS allocation delay of emergency data decreasing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12C
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• pp.1184-1191
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• 2009

We aim at frequency offset estimation for IEEE 802.15.4a ranging systems, where an impulse-radio ultra-wideband (IR-UWB) signal is exploited, By incorporating the property of the ternary code in the preamble, we derive a simplified maximum-likelihood (ML) estimation of the frequency offset. In addition, a closed form estimator for implementation is investigated. Simulation results and theoretical analysis verify our estimators in IEEE 802.15.4a IR-UWB packet-based ranging systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1954-1959
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• 2006

In this paper, we proposed TH UWB-IR medical image transmission system using the IEEE an. 802.15.4a specification in WPAN environment. Also, we analyzed reception performance of wireless medical image transmission system in indoor multi-path fading environment using ITU-R M.1225 channel model. As a results, the proposed scheme can solve the problem of interference from the medical equipment in same frequency band, and minimize the loss due to the indoor multi-path fading environment. Therefore, the transmission with low power usage is possible.

• Journal of Communications and Networks
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• v.15 no.1
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• pp.87-101
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• 2013

In industrial applications, sensor networks have to satisfy specified time requirements of exchanged messages. IEEE 802.15.4 defines the communication protocol of the physical and medium access control layers for wireless sensor networks, which support real-time transmission through guaranteed time slots (GTSs). In order to improve the performance of IEEE 802.15.4 in industrial applications, this paper proposes a new traffic scheduling algorithm for GTS. This algorithm concentrates on time-critical industrial periodic messages and determines the values of network and node parameters for GTS. It guarantees real-time requirements of periodic messages for industrial automation systems up to the order of tens to hundreds of milliseconds depending on the traffic condition of the network system. A series of simulation results are obtained to examine the validity of the scheduling algorithm proposed in this study. The simulation results show that this scheduling algorithm not only guarantees real-time requirements for periodic message but also improves the scalability, bandwidth utilization, and energy efficiency of the network with a slight modification of the existing IEEE 802.15.4 protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.669-677
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• 2011

Superframe in IEEE 802.15.4 Standard is subdivided into an active period and an inactive period to reduce energy consumption. But communication nodes use same data transmission range in an active period, thus communication nodes spend a lot of energy to send data another nodes. In this paper, we proposed reduce energy consumption algorithm that nodes use different transmission power. Cordinator split transmission area into four group and transmit becon message to nodes. Nodes adjust transmission power according to becon message and wates lowe energy than normal nodes. We proposed energy-efficient cross layer protocol that have different PAN (Personal Area Network) by four range group.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.181-182
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• 2009

본 논문에서는 IEEE 802.15.4a 근거리 무선 네트워크를 이용하여 다중 이동 로봇을 사용자 휴대 단말을 이용하여 실시간으로 편리하게 제어하기 위한 플랫폼을 설계하고 그 기본기능을 검증한다. 제안한 원격제어 플랫폼은 IEEE 802.15.4a 기반의 최초의 원격제어 플랫폼으로서 그 의의를 가지며, 자동 스페이싱(auto-spacing)을 기반한 다중 로봇 그룹이동과 IEEE 802.15.4a의 거리측정 기능과 초음파 및 자이로센서를 이용한 상대각측정 기능을 이용한 협동위치인식(cooperative localization) 기능을 제공하는데 기존 기법들과의 차별성이 존재한다.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.4
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• pp.148-155
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• 2009

Precise localization heavily relies on the accuracy of its underlying ranging technique. It has been known that the Chirp Spread Spectrum (CSS) defined in the IEEE 802.15.4a provides more dependable ranging accuracy than the Received Signal Strength Indicator (RSSI) in the IEEE 802.15.4. This paper examines the accuracy of the CSS-based ranging technique in the indoor/outdoor environments and discovers its consistent inaccuracy in different environments. Next, it proposes an error-correction architecture for the CSS-based ranging technique that exploits the per-environment consistent inaccuracy information and user visiting patterns (represented by weights for each environment).