• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.97-104
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• 2008

Location-based services provide customized information or services according to the user's location. The existing localization schemes for outdoor environment are not applicable to the indoor localization system which requires higher accuracy of location estimation than that of the outdoor localization system. In this paper, we employ the received signal strength(RSS) to approximate the distance between a moving target and a reference point and use the triangulation method to estimate the location of the moving target for the indoor localization system in IEEE 802.15.4 wireless PAN(personal area network). For the indoor localization system, we propose a scheme which selects the best reference points to enhance the localization accuracy and adaptively reflects the changes in propagation environments of a moving target to the distance approximation. Through the implementation of the localization system, we have verified the performance of the proposed scheme in terms of the estimation accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1066-1074
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• 2008

In this paper, we proposed an efficient algorithm using pulse signal based on group-node-contention in LR-WPAN. The purpose of IEEE 802.15.4 is low speed, low cost and low power consumption. Recently, as applications of LR-WPAN have been extended, there is a strong probability of collision as well and almost collision occurs because of hidden node problem. Moreover, if the collision continuously occurs due to hidden node collision, network performance could be decreased. Nowadays, although several papers focus on the hidden node collision, algorithms waste the channel resource if continuous collisions frequently occur. In this paper, we assume that PAN has been already formed groups, and by using pulse signal, coordinator allocates channel and orders, and then, nodes in the allocated group can compete each other. Hence, contention nodes are reduced significantly, channel wastage caused by collision is decreased, and data transmission rate is improving. Finally, this algorithm can protect the network from disruption caused by frequent collisions. Simulation shows that this algorithm can improve the performance.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.137-138
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• 2006

NEMO(Network MObility) is a complex model of mobile network which refers to a forming of Nested Mobile Network by a moving transportation like vessel, bus, or a train which then moves a Mobile Node, or by a movement of a PAN(Personal Area Network). In a Nested NEMO, pinball routing is the primary obstacle as exemplified by the IPv6 environment. This paper will focus on improving such models as RRH, RBU+ and MANET Approach, that attempted to solve pinball routing by route optimization.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.271-273
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• 2001

최근들어 블루투스 기술은 정보 기기간의 케이블 통신을 대체하는 저가격의 무선 통신 기술로서 많은 관심을 끌고 있으며 블루투스 칩, 프로토콜 스택 및 응용 제품 개발이 활발히 진행되고 있다. 특히 블루투스는 1개의 마스터와 최대 7개의 슬레이브로 구성되는 피코넷과 다수의 피코넷으로 구성되는 스캐터넷의 형성이 가능하여 이를 이용한 ad hoc PAN 네트워킹에 대한 연구가 시작되고 있다. 블루투스 ad hoc PAN 연구를 위해서는 시뮬레이터의 이용이 필수적이다. 본 논문은 블루투스 피코넷에서의 ad hoc 네트워킹을 위한 Glomosim 기반 시뮬레이터의 설계 및 구현에 관한 내용이다. 이 시뮬레이터는 Glomosim 시뮬레이터의 MAC 계층 모듈에 블루투스 baseband 및 LM 래이어를 추가하여 ad hoc IP 라우팅이 가능하도록 설계되어 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8A
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• pp.656-663
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• 2005

This paper presents a multi-channel enhancement scheme for the MAC protocol of IEEE 802.15.3 High-rate WPAN (Wireless Personal Area Network). The current MAC protocol of the IEEE 802.15.3 High-rate WPAN is designed for sharing a single channel among DEVs of a piconet; that is, within a single piconet, PNC prevents interference through MAC layer assignment of time slots to other DEVs using time-division multiple access. When the number of DEVs that communicate with each other frequently, is increased in a single WPAN, the size of the superframe becomes inevitably large, and this may result in a significant throughput drop or a failure to provide QoS guarantee. A multi-channel enhancement scheme for the MAC protocol of IEEE 802.15.3 High-rate WPAN is proposed to significantly increase the aguegate throughput and more reliably provide the QoS guarantees in a piconet

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.9-14
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• 2008

In this paper, we propose the channel sounding scheme which is made for ideal communication between some application as well as the short distance of high speed data transmission in MIMO-OFDM system for Wireless PAN. This method is able to perceive the duration of the impulse response through the delaying of power delay profile, modeled a power delay profile which has an attenuate characteristic, and obtained the coefficient of channel response by ML (maximum likelihood). Through the amplitudes, phases and delays associated with each multipath component which were acquired from this channel sounding scheme, we can describe the wave propagation characteristics of channels between the transmitter and receiver so that the receiver could enhance not only the reliability but also the ability of communication link.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.787-790
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• 2015

Recently, M2M (Machine to Machine) communication is possible the development of MTC (Machine Type Communication) devices becomes active. MCT devices in the form of home appliances have a low power consumption, low cost, short-range wireless communication in wireless home network. For purpose, MTC devices based on IEEE 802.15.4/Zigbee are composed in the form of cluster-tree topology, which consists of one PAN (Personal Area Network), one or other router and end of nodes. It happens that transmission delay, packet drop, and lacking data resulted from collision originated by a competition for allocating channels among MTC devices that greatly increased. At last performance of entire network can be degradated. This paper proposes that the beacon frame-based grouping algorithm using multiple channels in a MTC devices in the presence of wireless home network interference. The proposed algorithm decreases the transmission delay, dropped packet and throughput is more increase, so the proposal algorithm is more efficient than the IEEE 802.15.4/ Zigbee standard.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9A
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• pp.712-718
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• 2009

This paper proposes the optimal transmission parameter selection method for an energy efficient Wireless Personal Area Network (WPAN) system which is applicable to the Maritime Telematics targeting for various ship models. Since the transmission parameter selection is an important factor for WPAN system to decide its energy efficiency, we propose an energy consumption model for ship area network (SAN) employing IEEE 802.15.3 based TDMA HR-WPAN model and analyzes the effect of transmission parameter selection on the performance of energy consumption. In particular, the main performance decision parameter of the SAN applying HR-WPAN is path loss, since it is very varied according to the material of shipbuilding such as steel (large ship), FRP (medium size ship) and compound wood (small ship). Thus, we analyzed and demonstrated that the proper transmission parameter selection among transmit power, PHY data rate and fragment size for each ship model guarantee the energy efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10A
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• pp.769-775
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• 2009

This paper proposes the optimal transmission parameter selection method for an energy efficient Wireless Personal Area Network (WPAN) system which is applicable to the Maritime Telematics targeting for various ship models. Since the transmission parameter selection is an important factor for WPAN system to decide its energy efficiency, we propose an energy consumption model for ship area network (SAN) employing IEEE 802.15.3 based TDMA HR-WPAN model and analyzes the effect of transmission parameter selection on the performance of energy consumption. In particular, the main performance decision parameter of the SAN applying HR-WPAN is path loss, since it is very varied according to the material of shipbuilding such as steel (large ship), FRP (medium size ship) and compound wood (small ship). Thus, we analyzed and demonstrated that the proper transmission parameter selection among transmit power, PHY data rate and fragment size for each ship model guarantee the energy efficiency.

• Journal of information and communication convergence engineering
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• v.11 no.1
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• pp.7-11
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• 2013

Wearable computer systems use the wireless universal serial bus (WUSB), which refers to USB technology that is merged with WiMedia physical layer and medium access control layer (PHY/MAC) technical specifications. WUSB can be applied to wireless personal area network (WPAN) applications as well as wired USB applications such as PAN. WUSB specifications have defined high-speed connections between a WUSB host and WUSB devices for compatibility with USB 2.0 specifications. In this paper, we focus on an integrated system with a WUSB over an IEEE 802.15.6 wireless body area network (WBAN) for wireless wearable computer systems. Due to the portable and wearable nature of wearable computer systems, the WUSB over IEEE 802.15.6 hierarchical medium access control (MAC) protocol has to support power saving operations and integrate WUSB transactions with WBAN traffic efficiently. In this paper, we propose a low-power hibernation technique (LHT) for WUSB over IEEE 802.15.6 hierarchical MAC to improve its energy efficiency. Simulation results show that the LHT also integrates WUSB transactions and WBAN traffic efficiently while it achieves high energy efficiency.