Search results for "Networks"
showing 10 items of 3260 documents
Wireless Sensor Networks for Condition Based Maintenance: Security and Reliability
2009
Masteroppgave i informasjons- og kommunikasjonsteknologi 2009 – Universitetet i Agder, Grimstad In this thesis we present the requirements needed for a Condition Based Main- tenance (CBM) solution by using Wireless Sensor Networks(WSN). The sensor network needs to be secure and reliable to be implemented in a CBM solution, hence we have chosen the popular ZigBee protocol to see how it fulfill the reliability requirements of transmission delay, lost packets and battery consumption. The security requirements is based on the CIA(confidentiality, integrity, availability) triad for security objectives, and in this thesis we will give a general overview of the security mechanisms used in ZigBee t…
Performance evaluation of robust header compression protocol for low data rate networks
2013
Masteroppgave i informasjons- og kommunikasjonsteknologi IKT590 2013 – Universitetet i Agder, Grimstad Mobile Ad hoc networks (MANETs) have limited capacity due to properties of the physical medium for tactical operations. Several traffic types are typical for tactical applications, i.e. transmit frequent short IP packets (e.g., VoIP and friendly force tracking message). The RTP, TCP/UDP and IP headers comprise a significant overhead for these traffic types. Therefore, robust header compression (ROHC) protocol can useful to save the bandwidth for such applications. This thesis work is divided into two tasks. First one is the technological background of the robust header compression (ROHC) p…
A dynamic parallel-rendezvous MAC mechanism in multi-rate cognitive radio networks: Mechanism design and performance evaluation
2009
Published version of an article published in the journal:Journal of Communications, © Academy Publisher Also available from publisher: http://dx.doi.org/10.4304/jcm.4.10.752-765 Parallel rendezvous multi-channel MAC mechanisms are regarded as an efficient method for media access control in cognitive radio networks since they do not need a control channel and use only one transceiver. However, existing parallel rendezvous MAC mechanisms assume that all channels have the same maximum capacity and channel availability for secondary users. In this paper, we propose a dynamic parallel rendezvous multi-channel MAC mechanism for synchronized multi-rate cognitive radio networks in which secondary u…
Energy Efficiency inWireless Sensor Networks: Transmission Protocols and Performance Evaluation
2016
Doktorgradsavhandling, Fakultet for teknologi og realfag, Universitetet i Agder, 2016 Energy efficiency is one of the major goals for achieving green wireless communications. The recent growth in ubiquitous wireless connections and multimedia applications demands higher energy efficiency for wireless communications. As a part of this picture, wireless sensor networks (WSNs) need to be more energy efficient since the battery capacity of nodes in such networks is limited in the absence of energy harvesting sources. In general, an energy efficient protocol should perform as few as possible operations when delivering user information successfully across the network. Energy efficient data transm…
A Single radio based channel datarate-aware parallel rendezvous MAC protocol for cognitive radio networks
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/LCN.2009.5355152 Channel hopping based parallel rendezvous multichannel MAC protocols have several advantages since they do not need a control channel, require only one transceiver, and produce higher system capacity. However, channel hopping sequences in existing parallel rendezvous MAC protocols…
Cooperative RTS/CTS MAC with relay selection in distributed wireless networks
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/ICUMT.2009.5345396 This paper proposes a cooperative multiple access protocol based on the distributed coordination function (DCF) request-to-send/clear-to-send (RTS/CTS) scheme for distributed wireless networks. It answers three key questions concerning cooperation from the network perspective, n…
Cooperative medium access control in wireless networks: The two-hop case
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE." Article also available from publisher: http://dx.doi.org/10.1109/WiMob.2009.13 Cooperative communication has been recently proposed as a powerful means to improve network performance in wireless networks. However, most existing work focuses solely on one-hop source-destination cooperation. In this paper, we propose a novel cooperative MAC mechanism that is spe…
Optimization of the relay selection scheme in cooperative retransmission networks
2011
Accepted version of a paper in the book: 2011 IEEE 73rd Vehicular Technology Conference (VTC Spring). Published version available from the IEEE:http://dx.doi.org/10.1109/VETECS.2011.5956485 Cooperative MAC protocol design has attracted much attention recently thanks to the development of relaying techniques. In single-relay C-ARQ, the relay selection scheme cannot work efficiently in a dense network, due to high collision probability among different contending relays. In this paper, the throughput performance impairment from the collision is analyzed in a typical network scenario. Thereby, we propose an optimized relay selection scheme aiming at maximizing system throughput by reducing coll…
An automatic cooperative retransmission MAC protocol in wireless local area networks
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/EW.2009.5357992 Existing solutions for cooperation in wireless networks either require simultaneous transmission of source and relay nodes or impose major modifications to original MAC protocols. In this paper, a new efficient retransmission MAC protocol is proposed for IEEE 802.11 based cooperati…
An optimal energy efficient cooperative retransmission MAC scheme in wireless networks
2011
Accepted version of a paper in the book: 2011 2nd Wireless Communication, Vehicular Technology, Information Theory and Aerospace & Electronic Systems Technology (Wireless VITAE). Published version available from the IEEE: http://dx.doi.org/10.1109/WIRELESSVITAE.2011.5940871 While the benefits of cooperative diversity have been well studied in the literature, cooperative MAC protocol design has also attracted much attention recently. In the single-relay Cooperative Automatic Repeat reQuest (C-ARQ) protocol, the best relay node is selected in a distributed manner by relays using different backoff time before packet retransmission. However, this relay selection scheme does not work efficiently…