• Title/Summary/Keyword: Source Node

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CPN Management Model and Network Access Flow/Congestion Control in ATM Network (CPN의 관리 모델과 망 엑세스 흐름/혼잡 제어)

  • 김양섭;권혁인;김영찬
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.8
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    • pp.2096-2105
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    • 1998
  • As there can be coincident bursts which may result in congetsion in a node of ATM network, reactive flow control schemes are required to guarantee user's Quality of Service. But, the high speed characteristics of ATM networks make it difficult to control source transmission rate in reacting to congestions in intermediate nodes. Therefore, flow control in Customer Premise Network may be more efficient than end-to-end flow control. In this paper, we propose a management model for flow ontrol in CPN and new Network Access Flow/Congestsion control scheme to utilize efficiently Virtual Path Connection.

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An Enhanced Cross-layer Geographic Forwarding Scheme for Wireless Sensor Networks (무선 센서 네트워크에서 향상된 교차 계층 방식의 위치기반 데이터 전달 기법)

  • Kim, Jae-Hyun;Kim, Seog-Gyu;Lee, Jai-Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.8B
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    • pp.712-721
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    • 2012
  • In this paper, we propose an Enhanced cross-layer Geographic Forwarding (EGF) protocol for wireless sensor networks (WSNs). EGF uses an optimal back-off time to make the packet forwarding decisions using only source and destination's location information and energy cost without information about neighbor nodes' location or the number of one hop neighbor nodes. EGF is also a cross-layer protocol by combining efficient asynchronous MAC and geographic routing protocol. The proposed protocol can find optimal next hop location quickly without broadcasting node's location update and with minimizing overhead. In our performance evaluation, EGF has better performance in terms of packet success ratio, energy efficiency and end-to-end delay in wireless sensor networks.

Comparison of Outage Probability Between Best-relay 2-hop Relaying and 3-hop Relaying (두 릴레이가 존재할 때 삼중 홉 중계와 베스트 릴레이 선택 후 이중 홉 중계 방식의 아웃티지 확률 비교)

  • Youn, You-Sun;Kim, Dong-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.1B
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    • pp.136-143
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    • 2010
  • In this paper, we investigate decode-and-forward (DF) relaying systems with a direct link between the source and the destination node. The objective of this paper is to determine the better relaying strategy between 3-hop DF relaying and dual-hop DF relaying with the best relay selection. Assuming Rayleigh fading channels, we present closed-form outage probability of the 3-hop relaying and the dual-hop relaying, respectively, and compare the performances by numerical investigation. Numerical results show that if the channel is poor, the outage performance of the 3-hop relaying is better than the dual-hop relaying.

Optimal Amplify-and-Forward Scheme for Parallel Relay Networks with Correlated Relay Noise

  • Liu, Binyue;Yang, Ye
    • ETRI Journal
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    • v.36 no.4
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    • pp.599-608
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    • 2014
  • This paper studies a parallel relay network where the relays employ an amplify-and-forward (AF) relaying scheme and are subjected to individual power constraints. We consider correlated effective relay noise arising from practical scenarios when the relays are exposed to common interferers. Assuming that the noise covariance and the full channel state information are available, we investigate the problem of finding the optimal AF scheme in terms of maximum end-to-end transmission rate. It is shown that the maximization problem can be equivalently transformed to a convex semi-definite program, which can be efficiently solved. Then an upper bound on the maximum achievable AF rate of this network is provided to further evaluate the performance of the optimal AF scheme. It is proved that the upper bound can be asymptotically achieved in two special regimes when the transmit power of the source node or the relays is sufficiently large. Finally, both theoretical and numerical results are given to show that, on average, noise correlation is beneficial to the transmission rate - whether the relays know the noise covariance matrix or not.

Design of Communication System for Intelligent Multi Agent Robot System (지능형 멀티 에이전트 로봇시스템을 위한 통신시스템의 설계)

  • Kim, Jun-Yeup;Park, Seung-Min;Ko, Kwang-Eun;Jang, In-Hun;Sim, Kwee-Bo
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.8
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    • pp.758-767
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    • 2012
  • In the ad-hoc wireless network environment, that the fixed sensor nodes and the sensor nodes to move are mixed, as the number of the sensor nodes with mobility are getting more, the costs to recover and maintain the whole network will increase more and more. This paper proposed the CDSR (Cost based Dynamic Source Routing) algorithm being motivated from the typical DSR algorithm, that is one of the reactive routing protocol. The cost function is defined through measuring the cost which any sensor node pays to participate in the whole network for communication. It is also showed in this paper that the proposed routing algorithm will increase the efficiency and life of whole sensor network through a series of experiments.

Numerical Simulations of Added Resistance and Motions of KCS in Regular Head Waves (선수 규칙파 중 KCS의 부가저항 및 운동성능 수치해석)

  • Seo, Seonguk;Park, Sunho
    • Journal of the Society of Naval Architects of Korea
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    • v.54 no.2
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    • pp.132-142
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    • 2017
  • As the International Maritime Organization (IMO) recently introduced the Energy Efficiency Design Index (EEDI) for new ships building and the Energy Efficiency Operational Indicator (EEOI) for ship operation, thus an accurate estimation of added resistance of ships advancing in waves has become necessary. In the present study, OpenFOAM, computational fluid dynamics libraries of which source codes are opened to the public, was used to calculate the added resistance and motions of the KCS. Unstructured grid using a hanging-node and cut-cell method was used to generate dense grid around a wave and KCS. A dynamic deformation mesh method was used to consider the motions of the KCS. Five wavelengths from a short wavelength (${\lambda}/LPP=0.65$) to a long wavelength (${\lambda}/LPP=1.95$) were considered. The added resistance and the heave & pitch motions calculated for various waves were compared with the results of model experiments.

Coding-based Storage Design for Continuous Data Collection in Wireless Sensor Networks

  • Zhan, Cheng;Xiao, Fuyuan
    • Journal of Communications and Networks
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    • v.18 no.3
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    • pp.493-501
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    • 2016
  • In-network storage is an effective technique for avoiding network congestion and reducing power consumption in continuous data collection in wireless sensor networks. In recent years, network coding based storage design has been proposed as a means to achieving ubiquitous access that permits any query to be satisfied by a few random (nearby) storage nodes. To maintain data consistency in continuous data collection applications, the readings of a sensor over time must be sent to the same set of storage nodes. In this paper, we present an efficient approach to updating data at storage nodes to maintain data consistency at the storage nodes without decoding out the old data and re-encoding with new data. We studied a transmission strategy that identifies a set of storage nodes for each source sensor that minimizes the transmission cost and achieves ubiquitous access by transmitting sparsely using the sparse matrix theory. We demonstrate that the problem of minimizing the cost of transmission with coding is NP-hard. We present an approximation algorithm based on regarding every storage node with memory size B as B tiny nodes that can store only one packet. We analyzed the approximation ratio of the proposed approximation solution, and compared the performance of the proposed coding approach with other coding schemes presented in the literature. The simulation results confirm that significant performance improvement can be achieved with the proposed transmission strategy.

Differentiated Packet Transmission Methods for Underwater Sensor Communication Using SON Technique (SON (Self Organizing Network) 기술을 이용한 해양 수중 센서 간 통신에 있어서 데이터 중요도에 따른 패킷 차별화 전송 기법)

  • Park, Kyung-Min;Kim, Young-Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.4B
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    • pp.399-404
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    • 2011
  • For the underwater wireless sensor networks, we propose the packet transmission method which distinguishes more important packet than others. Because the ocean underwater transmission environments are extremely unstable, we use SON(Self Organizing Network) techniques to adapt to the constantly varying underwater acoustic communication channels and randomly deployed sensor nodes. Especially we suppose two kinds of packets which have different priorities, and through the simulations we show that high priority packets arrive at the source node faster than lower priority packets with a proposed scheme.

The effect of 1/f Noise Caused by Random Telegraph Signals on The Phase Noise and The Jitter of CMOS Ring Oscillator (Random Telegraph Signal에 의한 1/f 잡음이 CMOS Ring Oscillator의 Phase Noise와 Jitter에 미치는 영향)

  • 박세훈;박세현;이정환;노석호
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2004.05b
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    • pp.682-684
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    • 2004
  • The effect of 1/f noise by the random telegraph signal(RTS) on the phase noise and the jitter of CMOS ring Oscillator is investigated. 10 parallel piece-wise-linear current sources connected to each node model the RTS signals. The In, the power spectral density and the jitter of output of the ring oscillator are simulated as functions of the amplitude and time constant of RTS current source. It is confirmed that the increase of amplitude of RTS is directly related to the increase of the width of phase noise md the value of jitter. The shorter the time constant is, the wider width of FET peak and the larger value of cycle to cycle jitter are.

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Constructing κ-redundant Data Delivery Structure for Multicast in a Military Hybrid Network (군 하이브리드 네트워크에서 생존성 향상을 위한 다중 경로 멀티캐스팅)

  • Bang, June-Ho;Cho, Young-Jong;Kang, Kyungran
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.6
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    • pp.770-778
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    • 2012
  • In this paper, we propose a multi-path construction scheme to improve the survivability of a multicast session in military hybrid networks. A military hybrid network consists of a static backbone network and multiple mobile stub networks where some nodes are frequently susceptible to be disconnected due to link failure and node mobility. To improve the survivability of multicast sessions, we propose a construction scheme of ${\kappa}$ redundant multi-paths to each receiver. In order to take account of different characteristics of static and mobile networks, we propose quite different multi-path setup approaches for the backbone and stub networks, respectively, and combine them at the boundary point called gateway. We prove that our proposed scheme ensures that each receiver of a multicast session has ${\kappa}$ redundant paths to the common source. Through simulations, we evaluate the performance of the proposed schemes from three aspects : network survivability, recovery cost, and end-to-end delay.