• Title/Summary/Keyword: IEEE 802 15.3

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A Robust Coherent IR-UWB Channel Estimation Method Against Imperfect Synchronization (동기식 IR-UWB 시스템에서 불완전 동기 환경에 강인한 채널 추정 기법)

  • Hwang, In-Jae;Kim, Jeong-Been;Oh, Wang-Rok;Ahn, Jae-Min
    • 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.

Design and Performance Analysis of Real-Time Hybrid Position Tracking Service System using IEEE 802.15.4/4a in the Multi-Floor Building (복합환경에서 IEEE 802.15.4/4a를 이용한 하이브리드 실시간 위치추적 서비스 시스템 설계 및 성능분석)

  • Kim, Myung-Hwan;Chung, Yeong-Jee
    • Journal of Information Technology Services
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    • v.10 no.1
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    • pp.105-116
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    • 2011
  • With recent spotlight on the, uniquitous computing technology, the need for object of indentification and location infrastructure has increased. Such GPS technolgy must utilize IEEE 802.15.4 Zigbee used for existing wireless sensor network infra as a basice element for user's context-awareness in a uniquitous environement, for effectiveness.Such real-time GPS service is provided in the internal environment where the user would actually are and most high-rise buildlings apply. Underthe assumption, the real-time GPS technology is seperated by each floor, and signals do not get transmitted to other floors, the application on one floor within the high-rise buildling was conducted. This study intends to suggest a floor detection algorithm using IEE 802.15.3/Zigbee's RSSI which supports the accuracy within a couple of meters for the user's the movement between the floors in high-rise buildings in a complex environment. It proposes an floor detection algorithm using IEEE 802.15.4/Zigbee's RSSI which provides accuracy within a radius of few meters for the users movement between the floors for real-time location tracking within high-rise building in a cmoplex environment. Furthermore, for more accurate real-time location tracking, it suggests an algorithm for real-time location tracking using IEEE 802.15.4a/Zigbee's CSS technology based on triangulation. Based on the suggested algorithm, it designs a hybrid real-time location tracking service system in a high-rise buildling and test its functions.

Performance Enhancement Directional CSMA/CA Algorithm in mmWave Bands (밀리미터파 대역에서 지향성 CSMA/CA의 성능 향상을 위한 알고리즘)

  • Kim, Mee-Joung;Lee, Woo-Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.1B
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    • pp.15-20
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    • 2012
  • In this paper, an algorithm that enhances the conventional directional CSMA/CA protocol in IEEE 802.15.3c is proposed under saturation environments. For the algorithm, a Markov chain model is presented and analyzed in no-ACK mode. The effects of directional antennas and the features of IEEE 802.15.3c MAC are considered in the model. The optimal sizes of contention window are derived from the numerical results. The numerical results show that the proposed directional CSMA/CA algorithm outperforms conventional one. The overall analysis is verified by simulation. The obtained results provide the criterion for selecting the optimal parameters and developing a MAC protocol that enhances the performance of mmWave WPANs.

An analysis of Optimal Design Conditions of Multi-mode LDPC Decoder for IEEE 802.11n WLAN System (IEEE 802.11n WLAN용 다중모드 LPDC 복호기의 최적 설계조건 분석)

  • Park, Hae-Won;Na, Young-Heon;Shin, Kyung-Wook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.2
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    • pp.432-438
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    • 2011
  • This paper describes an analysis of optimal design conditions of multi-mode LDPC(low density parity check) decoder which supports three block lengths (648, 1296, 1944) and four code rates (1/2, 2/3, 3/4, 5/6) for IEEE 802.11n WLAN system. A fixed-point model of LDPC decoder, which adopts min-sum algorithm and layered decoding scheme, is implemented using Matlab. From fixed-point simulation results for various bit-width parameters such as internal bit-width, integer/fractional part bit-widths, optimal design conditions and decoding performance of LDPC decoder are analyzed.

A Study on PKI Mechanisms with distributed CA for IEEE 802.15.3 High Rate WPAN (IEEE 802.15.3 High Rate WPAN을 위한 분산된 인종기관을 가지는 PKI 메커니즘 연구)

  • 박정우;양대헌;송주석
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.14 no.3
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    • pp.125-135
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    • 2004
  • IEEE 802.15.3 High Rate WPAN is a mechanism for wireless home network such as PDAs, digital video camcoder, etc. While symmetric keys are used for MAC layer security, the process of establishing a secure membership or a secure relationship is outside of the scope of the standard. In addition, to prepare for ubiquitous environment in the near future, it is important to study the process of establishing a secure relationship between DEVs in different dependent piconets. This paper propose a secure model and a process of establishing a secure relationship using PKI without a ousted certificate authority.

Performance Analysis of Directional CSMA/CA for IEEE 802.15.3c under Saturation Environments

  • Kim, Mee-Joung;Kim, Yong-Sang;Lee, Woo-Yong
    • ETRI Journal
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    • v.34 no.1
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    • pp.24-34
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    • 2012
  • In this paper, the directional carrier sense multiple access/collision avoidance (CSMA/CA) protocol in the immediate acknowledgement mode for IEEE 802.15.3c is analyzed under saturation environments. For the analysis, a sensing region and an exclusive region with a directional antenna are computed probabilistically and a Markov chain model in which the features of IEEE 802.15.3c and the effects of using directional antennas are incorporated is analyzed. An algorithm to find the maximal number of concurrently transmittable frames is proposed. The system throughput and the average transmission delay are obtained in closed forms. The numerical results show the impact of directional antennas on the CSMA/CA media access control (MAC) protocol. For instance, the throughput with a small beamwidth of antenna is more than ten times larger than that for an omnidirectional antenna. The overall analysis is verified by a simulation. The obtained results will be helpful in developing an MAC protocol for enhancing the performance of mmWave wireless personal area networks.

Data Transmission Rate Improvement Scheme Using Multicast ACK in IEEE 802.15.3 (IEEE 802.15.3에서 Multicast ACK를 이용한 전송률 향상 기법)

  • Jeong, Pil-Seong;Kim, Hwa-Sung;Oh, Young-Hwan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.10
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    • pp.35-42
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    • 2011
  • WPAN(Wireless Personal Area Network) have many advantages such as using low power and cheap price, small size. So it is recently increasing application range such as personal portable device, home network and sensor network so and on. IEEE 802.15.3 basically has the point to point or peer to peer UM(Usage Model). But using devises that need data transmission is increasing in the house and office. Therefor UM of point to multipoint is proposed. In this paper, I proposed Multicast ACK mechanism on the point to multipoint UM. So it is able to transfer data to multiple devices as this Multicast transfer method at a time. Thus, throughput performance is improved. But the problem that increases data transfer delay is appeared because of adding Multicast ACK traffic. We compared the performance between standard and proposed mechanism through a numerical analysis.

A Locating Scheme for Moving Objects Based on IEEE 802.15.4a (IEEE 802.15.4a에 기반한 이동체 위치 인식 기술)

  • Han, Young-Kou;Park, Jun-Seok;Seong, Yeong-Rak;Oh, Ha-Ryoung
    • Journal of The Institute of Information and Telecommunication Facilities Engineering
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    • v.8 no.3
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    • pp.132-137
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    • 2009
  • In this paper, a position recognition system is designed, implemented, and tested using IEEE 802.15.4a PHY (CSS) hardware and Tiny OS environment. The system is designed with extensibility and flexibility. The system consists of five kinds of nodes which have different functions from each other. Three communication channels are used for collision avoidance. In each cell, an arbiter node is used to minimize message collisions. The proposed arbitration protocol is designed to support mobility of arbitrary target nodes. Target nodes calculates their locations with communications to four location reference nodes which are placed on the comers of each cell.

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