• Title/Summary/Keyword: Multi-Beacon

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A Beacon Scheduling for Mesh Topology in Wireless Sensor Networks (무선 센서 네트워크에서 메쉬 토폴로지를 위한 비컨 스케줄링)

  • Kim, Min-Jeong;Shim, Jun-Ho
    • The Journal of Society for e-Business Studies
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    • v.15 no.4
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    • pp.49-58
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    • 2010
  • The wireless sensor network technology becomes one of core technologies to make it possible to implement various e-business applications. Energy efficiency is an important issue in wireless sensor networks. IEEE 802.15.4, a representative international standard for wireless sensor networks, provides the beacon enabled mode for energy-efficient communication. However, the beacons may conflict each other when the network is of multi-hop topology such as mesh or cluster-tree topology with beacon-enabled mode. The beacon conflict causes the failure of synchronization between sensor nodes, and affects other nodes in the network in that unsynchronized nodes cannot participate in communication. In this paper, we suggest an energy-efficient beacon scheduling for the wireless sensor networks. Nodes can save their energy duringperiod and prevent beacon conflict using beacon scheduling. We implement the scheduling using QualNet, and evaluate the performance under mesh topology networks. It turns out that the proposed scheduling may improve the energy efficiency in the networks.

Analysis of Power-Saving Protocols through Beacon Interval in Multi-hop Ad Hoc Networks based on IEEE 802.11 (IEEE 802.11기반 다중 홉 Ad Hoc 망에서 Beacon 간격에 따른 Power-Saving 프로토콜의 성능분석)

  • 김동일;김동현
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.10a
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    • pp.141-144
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    • 2003
  • The mobile radio networks can be divided into networks that has the base station or the infrastructures like AP(Access Point) and Ad Hoc network that hasn't any infrastructures. As there aren't any fixed infrastructures in Ad Hoc Networks, mobile nodes should transmit the data only among mobile nodes themselves. To supplement these weakpoints of the two networks, many studies about Ad Hocs based on the 802.11 are in progress. In this thesis, we try to propose the efficiency of the suggested protocols by comparing and analyzing power saving protocols according to the Beacon intervals in multi hop Ad Hoc Networks based on IEEE 802.11.

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Analysis of Power-Saving Protocols through Beacon Interval in Multi-hop Ad Hoc Networks based on IEEE 802.11 (IEEE 802.11기반 다중 홉 Ad Hoc 망에서 Beacon 간격에 따른 Power-Saving 프로토콜의 성능분석)

  • 김동일;김동현
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.7
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    • pp.1415-1420
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    • 2003
  • The mobile radio networks can be divided into networks that has the base station or the infrastructures like AP(Access Point) and Ad Hoc network that hasn't any infrastructures. As there aren't any fixed infrastructures in Ad Hoc Networks, mobile nodes should transmit the data oかy among mobile nodes themselves. To supplement these weakpoints of the two networks, many studies about Ad Hon based on the 802.11 are in progress. In this thesis, we try to propose the efficiency of the suggested protocols by comparing and analyzing power saving protocols according to the Beacon intervals in multi hop Ad Hoc Networks based on IEEE 802.11.

A Low-Delay MAC(LD-MAC) protocol in Multi-Hop Wireless Sensor Networks (멀티 홉 무선 센서 네트워크에서 저 지연을 지원하는 MAC 프로토콜)

  • Jeon, Jun-Heon;Kim, Seong-Cheol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.2
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    • pp.452-458
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    • 2014
  • In Wireless Sensor Networks the Medium access control (MAC) protocol has many challenges to solve such as reducing energy consumption, supporting QoS(quality of service) fairness, and reducing delivery delay. This paper proposed a low-delay supporting MAC protocol in multi-hop Wireless Sensor Networks. The proposed protocol uses the RB(rapid beacon) frame for reducing delivery delay. The RB frame is a modified IEEE 802.15.4 beacon frame. For sender adaptive-wakeup, the RB frame includes a seed number for determining of a receiver wakeup time. And for next hop receiver adaptive-wakeup, the RB frame includes the length of remaining data packet information. Results showed that our LD-MAC protocol outperformed other protocol in terms of data packet delivery delay.

Multi-Hop Clock Synchronization Based on Robust Reference Node Selection for Ship Ad-Hoc Network

  • Su, Xin;Hui, Bing;Chang, KyungHi
    • Journal of Communications and Networks
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    • v.18 no.1
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    • pp.65-74
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    • 2016
  • Ship ad-hoc network (SANET) extends the coverage of the maritime communication among ships with the reduced cost. To fulfill the growing demands of real-time services, the SANET requires an efficient clock time synchronization algorithm which has not been carefully investigated under the ad-hoc maritime environment. This is mainly because the conventional algorithms only suggest to decrease the beacon collision probability that diminishes the clock drift among the units. However, the SANET is a very large-scale network in terms of geographic scope, e.g., with 100 km coverage. The key factor to affect the synchronization performance is the signal propagation delay, which has not being carefully considered in the existing algorithms. Therefore, it requires a robust multi-hop synchronization algorithm to support the communication among hundreds of the ships under the maritime environment. The proposed algorithm has to face and overcome several challenges, i.e., physical clock, e.g., coordinated universal time (UTC)/global positioning system (GPS) unavailable due to the atrocious weather, network link stability, and large propagation delay in the SANET. In this paper, we propose a logical clock synchronization algorithm with multi-hop function for the SANET, namely multi-hop clock synchronization for SANET (MCSS). It works in an ad-hoc manner in case of no UTC/GPS being available, and the multi-hop function makes sure the link stability of the network. For the proposed MCSS, the synchronization time reference nodes (STRNs) are efficiently selected by considering the propagation delay, and the beacon collision can be decreased by the combination of adaptive timing synchronization procedure (ATSP) with the proposed STRN selection procedure. Based on the simulation results, we finalize the multi-hop frame structure of the SANET by considering the clock synchronization, where the physical layer parameters are contrived to meet the requirements of target applications.

BLE Signals-based Machine Learning for Determining Indoor Presence (BLE 신호 기반 기계학습을 이용한 재실 여부 결정 방법)

  • Kim, Seong-Chang;Kim, Jin-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.12
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    • pp.1855-1862
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    • 2022
  • Various indoor location-based services can be provided through indoor presence determination and indoor positioning technology using Beacon. However, since the BLE signal advertised by the beacon has an unstable RSSI due to problems such as multi-path fading, it is difficult to guarantee the accuracy of indoor presence determination. In this paper, data were collected while the classroom door was open to ensure accuracy in various situations. Based on the collected data, we propose an indoor presence determination method considering the characteristics of the signal. The proposed method uses support vector machine, showed about 10% accuracy improvement compared to the results using raw RSSI only. This method has the advantage of being able to accurately determine indoor presence with only one receiver. It is expected that the proposed method can implement a low-cost system for determining indoor presence with high accuracy.

Beacon Geolocation Scheme of COSPAS-SARSAT System for Heavy Disaster Environment (다중 재난 상황에 적합한 COSPAS-SARSAT 탐색구조 비컨 위치추정 기법)

  • Kim, Jaehyun;Lee, Sanguk;Sin, Cheonsig;Ahn, Woo-Geun
    • Journal of Satellite, Information and Communications
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    • v.10 no.4
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    • pp.146-150
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    • 2015
  • The COSPAS-SARSAT committee decides MEOSAR (Medium-Earth Orbit for search and rescue) service development for installing 406MHz SAR instruments on their respective MEO navigation satellite system of the United States, EU, and Russia, since 2000. The transmitted beacon signal is separately arrived by satellites with different FOA (Frequency of Arrival) and TOA (Time of Arrival). It is directly transferred to MEOLUT. In MEOLUT, a LUT track at least 3 or 4 satellites simultaneously and estimate location of beacon using time difference of arrival (TDOA) and frequency difference arrival (FDOA). But the transmitted distress signals may be overlapped each other because the distress beacons transmit signal on mean interval of 50 seconds in arbitrary time. It's difficult that simultaneously estimate location of beacon by current scheme for several overlapped distress signal. So we use cross ambiguity function (CAF) Map algorithm and present Multi-CAF MAP scheme in order to satisfy performance requirement of system. The performance is analyzed for COSAPS-SARSAT MEOSAR.

ANN-based Adaptive Distance Measurement Using Beacon (비콘을 사용한 ANN기반 적응형 거리 측정)

  • Noh, Jiwoo;Kim, Taeyeong;Kim, Suntae;Lee, Jeong-Hyu;Yoo, Hee-Kyung;Kang, Yungu
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.5
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    • pp.147-153
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    • 2018
  • Beacon enables one to measure distance indoors based on low-power Bluetooth low energy (BLE) technology, while GPS (Global Positioning System) only can be used outdoors. In measuring indoor distance using Beacon, RSSI (Received Signal Strength Indication) is considered as the one of the key factors, however, it is influenced by various environmental factors so that it causes the huge gap between the estimated distance and the real. In order to handle this issue, we propose the adaptive ANN (Artificial Neural Network) based approach to measuring the exact distance using Beacon. First, we has carried out the preprocessing of the RSSI signals by applying the extended Kalman filter and the signal stabilization filter into decreasing the noise. Then, we suggest the multi-layered ANNs, each of which layer is learned by specific training data sets. The results showed an average error of 0.67m, a precision of 0.78.

Design and Implementation of Beacon based Wireless Sensor Network for Realtime Safety Monitoring in Subway Stations (지하철 역사에서 실시간 안전 모니터링 위한 비컨 기반의 무선 센서 네트워크 설계 및 구현)

  • Kim, Young-Duk;Kang, Won-Seok;An, Jin-Ung;Lee, Dong-Ha;Yu, Jae-Hwang
    • Journal of the Korean Society for Railway
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    • v.11 no.4
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    • pp.364-370
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    • 2008
  • In this paper, we proposed new sensor network architecture with autonomous robots based on beacon mode and implemented real time monitoring system in real test-bed environment. The proposed scheme offers beacon based real-time scheduling for reliable association process with parent nodes and dynamically assigns network address by using NAA (Next Address Assignment) mechanism. For the large scale multi-sensor processing, our real-time monitoring system accomplished the intelligent database processing, which can generate not only the alert messages to the civilians but also process various sensing data such as fire, air, temperature and etc. Moreover, we also developed mobile robot which can support network mobility. Though the performance evaluation by using real test-bed system, we illustrate that our proposed system demonstrates promising performance for emergence monitoring systems.

The Study of Microwave Propagation Model for the Active ETC System (능동방식 ETC 시스템을 위한 마이크로파 전파 모델 연구)

  • 배창호;정희창;김영주;장호성
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 1999.11a
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    • pp.101-105
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    • 1999
  • Electronic Toll Collection(ETC) System makes the telecommunication possible between the Beacon and the On Board Unit(OBU) in vehicle at the highway. In this paper, the propagation path of microwave is modelled and the induced voltage of receiving antenna is analyzed numerically according to multi-path fading effort. In this modelling, we consider the weather condition, polarization and antenna radiation pattern. Also, we suggest the diversity technique in order to re duce the fading effect. In the result, the lading effort is reduced significantly in case of the vertical polarization at the rain condition. The circular polarization is the most desirable in this application. The antenna which has the high directivity, is also desirable. Using the space diversity technique at the Beaten, the fading effect is reduced as the distance increases between the Beacon and OBU. These results are presented at the graphs whose axes are related to the magnitude of received voltage(dB) and the distance of the beacon and a vehicle.

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