Dissertations / Theses: 'Wireless sensor networks energy-efficiency'

1

Prasad, Pratap Simha. "Energy efficiency in wireless sensor networks." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2007%20Spring%20Theses/PRASAD_PRATAP_30.pdf.

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2

Rault, Tifenn. "Energy-efficiency in wireless sensor networks." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2228/document.

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Dans cette thèse, nous avons proposé des solutions originales et performantes pour l’économie d’énergie dans les réseaux de capteurs sans fil (RCSF). Ces contributions s'organisent autour de deux grands axes : les réseaux de capteurs génériques et les réseaux de capteurs sans fil dédiés aux applications santé. Dans un premier temps, nous avons réalisé un état-de-l’art des mécanismes d'économie d’énergie pour les RCSF. Nous avons ensuite proposé deux solutions originales : la première optimise le déplacement d’une station de base, ainsi que la façon dont les données sont stockées dans les capteurs et routées vers le puit mobile ; la seconde optimise le déploiement de chargeurs mobiles, qui une fois dans le réseau permettent de satisfaire la demande en énergie des nœuds via la transmission d’énergie sans fil sur plusieurs sauts. Dans un second temps, nous nous sommes intéressés plus particulièrement aux applications des RCSF pour la supervision de patients à distance. Nous avons introduit une nouvelle classification des techniques économes en énergie adaptées à la spécificité de ces applications santé. Nous avons ensuite proposé une nouvelle architecture pour la supervision de patient à distance à l’aide de capteurs sans fil qui permet de prolonger la durée de vie des capteurs et de la station de base. Cette solution prend en compte l’environnement du patient et l’hétérogénéité des appareils. Nos résultats montrent que la durée de vie des réseaux de capteurs sans fil peut être étendue en utilisant les différentes stratégies proposées. L’efficacité de ces approches a été confirmée à l’aide de nombreuses expérimentations numériques et simulations In this thesis, we propose new strategies for energy conservation in wireless sensor networks, so that the operational time of these networks can be extended. The work can be divided into two main focus area, namely general wireless sensor networks, and healthcareoriented wearable sensor networks. In the first part of this thesis we provide a comprehensive survey of the existing energy-efficient mechanisms. Then, we propose two new solutions: the first one optimizes the displacement of a mobile base station as well as buffer usage and data routing at sensor nodes; the second one optimizes the deployment of wireless chargers in the network to satisfy the energy demand of the sensors. The second part of this thesis is dedicated to healthcare application where wearable sensors are used to remotely supervise a patient. We begin with a state-of-the-art of the energy-efficient techniques existing in the literature. We then introduce a new energy-efficient architecture that allows to optimize the lifetime of both the sensor and the base station. This is a context-aware solution that takes into consideration heterogeneous devices. Our results show that the lifetime of the sensor networks can be extended using the proposed strategies. All the results obtained are supported by numerical experiments and extensive simulations

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3

Zhu, Junhua. "Energy efficiency and reliability in wireless sensor networks /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CSED%202009%20ZHU.

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4

Busse, Marcel. "Algorithms for energy efficiency in wireless sensor networks." [S.l. : s.n.], 2007. http://madoc.bib.uni-mannheim.de/madoc/volltexte/2008/1809/.

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5

Cao, Hui. "Stabilization in wireless sensor networks." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1211079872.

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6

Vergara, Gallego Maria Isabel. "Smarter Radios for Energy efficiency in Wireless Sensor Networks." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENM020/document.

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Les contraintes présentes dans les réseaux de capteurs impliquent l'introduction de techniques d'optimisation à différents niveaux de conception : du matériel au logiciel et dans la pile de communication. En effet, le déploiement des réseaux de capteurs, à faible consommation énergétique, exige une conception conjointe du matériel et du logiciel adaptée à l'application visée. Étant donné la nature évènementielle et multitâche des applications dans les réseaux de capteurs, nous pourrions penser à rajouter différentes unités de traitement qui coopèrent pour gérer les évènements et les tâches de manière optimale. Ainsi, la complexité des tâches accomplies par le processeur principal peut être réduite, ce qui contribue à atteindre l'efficacité énergétique. Dans cette thèse nous étudions un ensemble de protocoles qui facilitent l'implémentation des smart radios. L'idée principale des smart radios est l'introduction de l'intelligence dans la puce radio de manière à ce qu'elle soit capable de prendre des décisions ainsi que d'exécuter plusieurs tâches de manière autonome et sans l'intervention du processeur principal. Cette dernière sera responsable du bootstrap du réseau et, après qu'un état stable est atteint, le processeur peut rester inactif la plupart du temps, alors que la puce radio continue à fournir un ensemble de services. Le protocole proposé est appelé Wake on Idle et il fournit la maintenance de voisinage intégrée avec une méthode d'accès au canal. Ces services sont basés sur des transmissions analogiques qui sont codées dans le temps. De cette manière, dès que le réseau entre dans l'état stable (c.à.d. la topologie est formée et les noeuds sont associés et synchronisés), le traitement numérique de trames n'est pas nécessaire. Puisque Wake on Idle est basé sur des informations de bas niveau, il peut être facilement intégré dans la puce radio et fonctionner comme un coprocesseur qui fournit des services de haut niveau au processeur principal, comme la maintenance du voisinage et l'accès au canal. Grâce à une analyse théorique et une implémentation préliminaire, nous démontrons la faisabilité du protocole et nous montrons plusieurs caractéristiques intéressantes qui aident à atteindre l'efficacité énergétique et de bonnes performances. Ensuite, nous exploitons la signalisation analogique afin d'optimiser le duty-cycle des protocoles d'accès au canal existants. Nous proposons également un mécanisme appelé Sleep on Idle qui est basé sur l'échange de signaux analogiques ou busy tones. Sleep on Idle peut être intégré dans la radio et il peut décider quand le processeur doit être réveillé. Enfin, nous avons intégré le mécanisme de notification dans le standard IEEE802.15.4 et nous avons évalué ce mécanisme par des simulations et expérimentations. Les résultats montrent un gain important en termes de consommation en énergie et de réactivité du réseau The constraints of Wireless Sensor Networks scenarios require the introduction of optimization techniques at different design levels: from the hardware to the software and communication protocol stack. In fact, the design of energy efficient WSNs involves an appropriate hardware/software co-design oriented to the concerned application. Given the event driven and multitasking nature of WSNs applications, one could think of adding different processing units that cooperate to manage events and tasks in an optimal way. Then, the complexity of tasks performed by the main processing unit can be reduced and energy efficiency can be achieved. In this PhD thesis we study protocols that leverage the implementation of smart radios. The idea of smart radios is introducing intelligence into the radio chip; in this way, it will be able to take decisions and perform several tasks in an autonomous way and without any intervention of the main processing unit. The processing unit will be in charge of bootstrapping the network and, after a stable state is reached, it can remain inactive most of the time while the radio chip provides a given set of services. The proposed protocol is called Wake on Idle and it provides integrated neighborhood maintenance and low duty-cycle medium access control. These services are provided based on analog transmissions that are time encoded; then, as soon as the network enters the stable state (i.e. the topology is formed and nodes are associated and synchronized) digital processing of frames is not needed. Since it relies on low-level information, Wake on Idle can be easily implemented on hardware and integrated into the radio chip; then, it works as a coprocessor that provides high-level services (i.e. neighborhood maintenance and medium access) to the main processing unit. Through theoretical analysis and a preliminary implementation we demonstrate the feasibility of the protocol and we show several interesting characteristics that help achieving energy efficiency and good performance. Then, we further exploit analog signaling to optimize duty cycle of existing medium access control protocols. We propose a mechanism called Sleep on Idle and it is based on the exchange of analog busy tones. Sleep on Idle can also be integrated into the smart radio to take decisions about whether the main processing unit has to be woken up. We apply the decision mechanism to the slotted ieee802.15.4 standard and validate it through simulations and experimentations. The results show an important gain in terms of energy consumption and network reactivity

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7

Ageev, Anton. "Time Synchronization and Energy Efficiency in Wireless Sensor Networks." Doctoral thesis, Università degli studi di Trento, 2010. https://hdl.handle.net/11572/367826.

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Time synchronization is of primary importance for the operation of wireless sensor networks (WSN): time measurements, coordinated actions and event ordering require common time on WSN nodes. Due to intrinsic energy limitations of wireless networks there is a need for new energy-efficient time synchronization solutions, different from the ones that have been developed for wired networks. In this work we investigated the trade-offs between time synchronization accuracy and energy saving in WSN. On the basis of that study we developed a power-efficient adaptive time synchronization strategy, that achieves a target synchronization accuracy at the expense of a negligible overhead. Also, we studied the energy benefits of periodic time synchronization in WSN employing synchronous wakeup schemes, and developed an algorithm that finds the optimal synchronization period to save energy. The proposed research improves state-of-the-art by exploring new ways to save energy while assuring high flexibility and reliable operation of WSN.

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8

Ageev, Anton. "Time Synchronization and Energy Efficiency in Wireless Sensor Networks." Doctoral thesis, University of Trento, 2010. http://eprints-phd.biblio.unitn.it/260/1/Ageev_PhD_Thesis.pdf.

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Time synchronization is of primary importance for the operation of wireless sensor networks (WSN): time measurements, coordinated actions and event ordering require common time on WSN nodes. Due to intrinsic energy limitations of wireless networks there is a need for new energy-efficient time synchronization solutions, different from the ones that have been developed for wired networks. In this work we investigated the trade-offs between time synchronization accuracy and energy saving in WSN. On the basis of that study we developed a power-efficient adaptive time synchronization strategy, that achieves a target synchronization accuracy at the expense of a negligible overhead. Also, we studied the energy benefits of periodic time synchronization in WSN employing synchronous wakeup schemes, and developed an algorithm that finds the optimal synchronization period to save energy. The proposed research improves state-of-the-art by exploring new ways to save energy while assuring high flexibility and reliable operation of WSN.

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9

Brownfield, Michael I. "Energy-efficient Wireless Sensor Network MAC Protocol." Diss., This resource online, 2006. http://scholar.lib.vt.edu/theses/available/etd-04102006-170423/.

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10

Barceló, Lladó Joan Enric. "Communications in Wireless Sensor Networks: Compression, Energy Efficiency and Secrecy." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/97359.

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Les xarxes de sensors sense fils (WSNs) han esdevingut un dels sistemes de comunicació amb més projecció d'aquesta dècada. Abasten una àmplia varietat d’aplicacions tals com la monitorització del medi ambient, la predicció de desastres naturals, en medicina, en transport, posicionament en interiors, i tasques militars. Els nodes que composen la xarxa, són típicament de baix cost, cosa que atorga una sèrie de limitacions en termes d’energia, velocitat de càlcul i d’ample de banda. Amb els avenços de les comunicacions sense fils i la creixent demanda de noves i més complexes aplicacions, les WSNs s’han d’optimitzar per tal de minimitzar aquestes limitacions. Aquesta tesi proposa un conjunt de tècniques que proporcionen a una WSN les següents característiques: 1. Implementació distribuïda sense necessitat de senyalització entre nodes sensors. 2. Comunicacions energèticament eficients. 3. Poca complexitat als nodes sensors. 4. Empra pocs recursos (temps, ample de banda, etc.) 5. Presenta un error quadràtic mig baix en reconstrucció al receptor. 6. Comunicacions secretes a capa física. Primer, s’estudia la transmissió seqüencial de mostreig reduït. Aquesta tècnica permet la disminució del nombre de transmissions i, per tant, reduir la despesa energètica associada a la comunicació a la xarxa. En particular, s’estudia el rendiment dels codificadors determinístics, probabilístics i condicionals de mostreig reduït per senyals autoregressius. S’obtenen expressions tancades de l’error quadràtic mig pel cas de mostreig reduït determinístic i probabilístic, mentre que pel cas condicional es deriven aproximacions ajustades. A continuació, s’analitza la compressió de la informació per WSNs grans. Pel cas on els paràmetres de correlació del senyal són desconeguts a priori, es proposen dos estimadors millorats: i) un per la predicció emprant el filtre de Wiener i ii) un per l’error quadràtic mig obtingut. Ambdós estimadors s’empren pels dos passos claus de l’algorisme de codificació distribuïda de canal. Aquests estimadors milloren notablement el rendiment de l’algorisme en comparació amb els estimadors de mostres clàssics, especialment quan la dimensió del vector d’observacions és comparable en magnitud amb el nombre de mostres usades a la fase d’entrenament de l’algorisme. Posteriorment, es proposa un esquema de comunicació distribuïda i energèticament eficient anomenat Amplify-and-Forward Compressed Sensing. Aquest esquema es basa en la tècnica de sensat comprimit i aprofita la correlació existent al senyal rebut per tal de reduir tant el nombre de recursos emprats com les despeses energètiques del sistema. Específicament, el sistema es dissenya seguint una funció de cost que controla el compromís existent entre error quadràtic i consum energètic de la xarxa. Per aconseguir aquest disseny, es deriva un model simple que aproxima el rendiment de l’esquema proposat en termes d’error quadràtic mig. A més, es contribueix a la teoria de sensat comprimit amb una nova i més ajustada relació entre el mínim nombre de mesures necessàries donades unes determinades propietats del senyal. Finalment, s’estudia l’esquema proposat Amplify-and-Forward Compressed Sensing des d’un punt de vista de secretisme a capa física. Es demostra que aquest esquema assoleix secretisme perfecte sota la presència d’un o d’un grup reduït d’espies, mentre que per un nombre més gran, és possible deteriorar notablement les seves capacitats d’espionatge gràcies a una tècnica proposta especialment dissenyada per introduir un extra d’incertesa solament a l’estimació dels espies. Wireless Sensor Networks (WSNs) have emerged as one of the most promising wireless communication systems in the last decade. They can be used in a wide variety of applications such as environmental monitoring, natural disaster prediction, healthcare, transportation, indoor positioning, and military tasks. The cost and the complexity of the nodes within a WSN are typically low, which results in constraints such as energy limitation, low computational speed, and reduced communication bandwidth. With the advances in wireless communications and the growing demand of new and more complex applications, WSNs must be optimized in order to overcome their intrinsic limitations in terms of complexity and power. In this dissertation, and according to these constraints, we propose a set of techniques that provide to a WSN the following interesting features: 1. Distributed operation without the need of signaling among sensing nodes. 2. Energy-efficient communications. 3. Low complexity at the sensing nodes. 4. Low resource (i.e., bandwidth, time, etc.) utilization. 5. Low distortion level at the receiver. 6. Secret communications at the physical layer. First, we study the zero-delay downsampling transmission. This technique allows the system to reduce the number of transmissions and hence decrease the total energy spent. In particular, we study the performance of deterministic, probabilistic and conditional downsampling encoding-decoding pairs for the case of the autoregressive signal model. We obtain closed form expressions for the quadratic error of the deterministic and probabilistic encoder-decoders, while accurate approximations are derived for the quadratic error of the conditional downsampling schemes. Second, we analyze data compression applied to large WSNs. For the realistic case where the correlation parameters are not known a priori, we obtain two enhanced correlation estimators: i) one for the linear Wiener filter vector and ii) one for the achieved mean square error. Both estimators are employed in the two key steps of the distributed source coding algorithm. These estimators notably improve the performance of the algorithm in comparison to the application of classical sample estimators, specially when the dimension of the observation vector is comparable in magnitude to the number of samples used in the training phase. Then, we propose a distributed and energy-efficient communication scheme named Amplify-and-Forward Compressed Sensing. This scheme is based on compressed sensing and exploits the correlation present in the signal in order to reduce both the resource utilization and the energy consumption. More specifically, the system is designed according to a cost function that controls the trade-off between the quadratic error in the reconstruction and the energy consumption of the network. In order to aid the system design, a simple model that accurately approximates the performance of the proposed scheme in terms of the quadratic error has been derived. Furthermore, we contribute to the compressed sensing theory with a tighter relationship between the minimum number of measurements that are required for a given network dimension and the sparsity level of the transmitted signal. Finally, the proposed Amplify-and-Forward Compressed Sensing scheme is also studied in terms of secrecy and wiretap distortion at the physical layer. It is shown that the proposed scheme is perfectly secret in the presence of one or even a small group of eavesdroppers whereas for a larger eavesdropping set, it is still possible to notably deteriorate its espionage capabilities thanks to a proposed technique specifically designed to introduce extra uncertainty only in the channel estimation of the eavesdroppers.

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11

Ali, Mahmood, and Kumar Ravula Sai. "Real-Time Support and Energy Efficiency In Wireless Sensor Networks." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1150.

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Wireless sensors nodes are made up of small electronic devices which are capable of sensing, computing and transmitting data from harsh physical environments like a surveillance field. These sensor nodes majorly depend on batteries for energy, which get depleted at a faster rate because of the computation and communication operations they have to perform. Communication protocols can be designed to make efficient utilization of energy resources of a sensor node and to obtain real time functionality. A set of previously reported routing and MAC (Medium Access Control) layer protocols has abilities to achieve energy efficiency and supports real-time functionality. A detailed study of these protocols has been carried out and comparison tables give an overview of the protocol’s performance on some factors like latency, scalability and energy awareness. Conclusions have been drawn using the comparison table parameters of how the protocol performs when utilized for a surveillance application and what kind of tradeoff they show. The conclusions and tabular information drawn here are from our theoretical analysis of protocols referred from journals; there is no simulation work done in this thesis.

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12

Zeng, Wenjie. "Topics in Energy Efficiency of Low-Power Wireless Sensor Networks." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354555977.

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13

Zhu, Yujie. "Energy-efficient Communication Strategies for Wireless Sensor Networks." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16157.

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Wireless sensor networks (WSNs) are characterized by limited amount of energy supply at sensor nodes. Hence, energy efficiency is an important issue in system design and operation of WSNs. In this work we focus on solving the energy efficiency problems of data gathering processes in WSNs. We first address this problem on a macroscopic level by investigating the efficiency of data gathering trees when data sent by different sensors are correlated. Such correlation aware data gathering strategies typically shift the aggregation structure from a default shortest-path tree (SPT) to a steiner minimum tree (SMT) in order to achieve the required efficiency. We study the energy efficiency of correlation aware data aggregation trees under various sensor network conditions and the tradeoffs involved in using them. Comprehensive simulation results as well as inferences and theoretical analysis of those results are presented in the thesis. Based on the insights gained through the investigation, we propose a simple, scalable and distributed correlation aware aggregation structure that achieves good energy performance across a wide range of sensor network configurations, and at the same time addresses the practical challenges of establishing a correlation aware data aggregation structure in resource-constrained WSNs. On a microscopic level, we propose a novel communication strategy called Communication through Silence (CtS) to achieve energy-efficient data gathering without significant degradation on overall throughput in WSNs. The proposed scheme primarily uses time, along with a minimal amount of energy to deliver information among sensors. CtS can be used to replace the conventional energy-based transmissions between each pair of sensor nodes during a data gathering process. We analyze in detail the primary energy-throughput tradeoff inherent in this approach as well as other challenges related to the realization of the proposed communication strategy. Finally, we propose a practical realization of CtS strategy that includes radio technology, MAC layer, and higher layer solutions. Performance evaluation results prove that this solution effectively realizes the CtS strategy in a WSN setting, at the same time achieves considerable energy savings compared to conventional communication strategies.

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14

Li, Jing. "Duty Cycling for Energy Efficiency in Wireless Sensor Networks and Applications." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1349110340.

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15

Khudhair, Ali Dheyaa. "A Simplified Routing Algorithm for Energy Efficiency in Wireless Sensor Networks." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1885751071&sid=8&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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16

Soua, Ridha. "Wireless sensor networks in industrial environment : energy efficiency, delay and scalability." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-00978887.

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Some industrial applications require deterministic and bounded gathering delays. We focus on the joint time slots and channel assignment that minimizes the time of data collection and provides conflict-free schedules. This assignment allows nodes to sleep in any slot where they are not involved in transmissions. Hence, these schedules save the energy budjet of sensors. We calculate the minimum number of time slots needed to complete raw data convergecast for a sink equipped with multiple radio interfaces and heterogeneous nodes traffic. We also give optimal schedules that achieve the optimal bounds. We then propose MODESA, a centralized joint slots and channels assignment algorithm. We prove the optimality of MODESA in specific topologies. Through simulations, we show that MODESA is better than TMCP, a centralized subtree based scheduling algorithm. We improve MODESA with different strategies for channels allocation. In addition, we show that the use of a multi-path routing reduces the time of data collection .Nevertheless, the joint time slot and channels assignment must be able to adapt to changing traffic demands of the nodes ( alarms, additional requests for temporary traffic ) . We propose AMSA , an adaptive joint time slots and channel assignment based on incremental technical solution. To address the issue of scalability, we propose, WAVE, a distributed scheduling algorithm for convergecat that operates in centralized or distributed mode. We show the equivalence of schedules provided by the two modes.

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17

Soua, Ridha. "Wireless sensor networks in industrial environment : energy efficiency, delay and scalability." Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066029.

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Certaines applications industrielles nécessitent des délais de collecte déterministes et bornés, nous nous concentrons sur l'allocation conjointe de slots temporels et de canaux sans conflit qui minimisent la durée de collecte. Cette allocation permet aux noeuds de dormir dans n'importe quel slot où ils ne sont pas impliqués dans des transmissions. Nous calculons le nombre minimal de slots temporels nécessaire pour compléter la collecte de données brute pour un puits équipé de plusieurs interfaces radio et des demandes de trafic hétérogènes. Nous donnons également des ordonnancements optimaux qui permettent d'atteindre ces bornes optimales. Nous proposons ensuite MODESA, un algorithme centralisé d'allocation conjointe de slots et de canaux. Nous montrons l'optimalité de MODESA dans des topologies particulières. Par les simulations, nous montrons que MODESA surpasse TMCP , un ordonnancement centralisé à base de sous-arbre. Nous améliorons MODESA avec différentes stratégies d'allocation de canaux. En outre , nous montrons que le recours à un routage multi-chemins réduit le délai de collecte.Néanmoins, l'allocation conjointe de slot et de canaux doit être capable de s'adapter aux changements des demandes des noeuds (des alarmes, des demandes de trafic supplémentaires temporaires). Nous proposons AMSA , une solution d'assignation conjointe de slots et de canaux basée sur une technique incrémentale. Pour aborder la question du passage à l'échelle, nous proposons, WAVE , une solution d'allocation conjointe de slots et de canaux qui fonctionne en mode centralisé ou distribué. Nous montrons l'équivalence des ordonnancements fournis par les deux modes Some industrial applications require deterministic and bounded gathering delays. We focus on the joint time slots and channel assignment that minimizes the time of data collection and provides conflict-free schedules. This assignment allows nodes to sleep in any slot where they are not involved in transmissions. Hence, these schedules save the energy budjet of sensors. We calculate the minimum number of time slots needed to complete raw data convergecast for a sink equipped with multiple radio interfaces and heterogeneous nodes traffic. We also give optimal schedules that achieve the optimal bounds. We then propose MODESA, a centralized joint slots and channels assignment algorithm. We prove the optimality of MODESA in specific topologies. Through simulations, we show that MODESA is better than TMCP, a centralized subtree based scheduling algorithm. We improve MODESA with different strategies for channels allocation. In addition, we show that the use of a multi-path routing reduces the time of data collection .Nevertheless, the joint time slot and channels assignment must be able to adapt to changing traffic demands of the nodes (alarms, additional requests for temporary traffic) . We propose AMSA , an adaptive joint time slots and channel assignment based on incremental technical solution. To address the issue of scalability, we propose, WAVE, a distributed scheduling algorithm for convergecat that operates in centralized or distributed mode. We show the equivalence of schedules provided by the two modes

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18

Ogunlu, Bilal. "Lifetime Analysis For Wireless Sensor Networks." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605226/index.pdf.

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Sensor technologies are vital today in gathering information about certain environments and wireless sensor networks are getting more widespread use everyday. These networks are characterized by a number of sensor nodes deployed in the field for the observation of some phenomena. Due to the limited battery capacity in sensor nodes, energy efficiency is a major and challenging problem in such power-constrained networks. Some of the network design parameters have a direct impact on the network&rsquo s lifetime. These parameters have to be chosen in such a way that the network use its energy resources efficiently. This thesis studies these parameters that should be selected according to certain trade offs with respect to the network&rsquo s lifetime. In this work, these trade offs have been investigated and illustrated in detail in various combinations. To achieve this goal, a special simulation tool has been designed and implemented in this work that helps in analyzing the effects of the selected parameters on sensor network&rsquo s lifetime. OMNeT++, a discrete event simulator, provides the framework for the sensor network simulator&rsquo s development. Ultimately, results of extensive computational tests are presented, which may be helpful in guiding the sensor network designers in optimally selecting the network parameters for prolonged lifetime.

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19

Haapola, J. (Jussi). "Evaluating medium access control protocols for wireless sensor networks." Doctoral thesis, University of Oulu, 2010. http://urn.fi/urn:isbn:9789514261152.

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Abstract Wireless sensor networks (WSNs) offer us a potential for greater awareness of our surroundings, collecting, measuring, and aggregating parameters beyond our current abilities, and provide an opportunity to enrich our experience through context-awareness. As a typical sensor node is small with limited processing power, memory, and energy resources, in particular, these WSNs must be very energy-efficient for practical deployment. Medium access control (MAC) protocols are central to the energy-efficiency objective of WSNs, as they directly control the most energy consuming part of a sensor node: communications over the shared medium. This thesis focuses on evaluating MAC protocols within the WSN domain by, firstly, surveying a representative number of MAC protocols and their features. Secondly, three novel MAC protocols are proposed, one for layered contention-based access, one for layered scheduled access, and one for cross-layer contention-based access. Thirdly, a novel energy consumption model is proposed, and fourthly, a holistic MAC protocol evaluation model is proposed that takes into account application emphasis on performance metrics. The MAC protocols are evaluated analytically. In addition, the layered contention-based MAC protocol has been implemented and measured, and the cross-layer contention-based protocol operating over an impulse radio-ultra wideband (IR-UWB) physical layer has been verified by simulations with relevant physical layer characteristics. The energy consumption evaluation model proposed is straightforward to modify for evaluating delay, and it can reuse state transition probabilities derived from throughput analysis. The holistic application-driven MAC protocol evaluation model uses a novel single compound metric that represents a MAC protocol's relative performance in a given application scenario. The evaluations have revealed several significant flaws in sensor MAC protocols that are adapted to sensor networking from ad hoc networks. Furthermore, it has been shown that, when taking sufficient details into account, single hop communications can outperform multi-hop communications in the energy perspective within the feasible transmission ranges provided by sensor nodes. The impulse radio physical layer introduces characteristics to MAC protocols that invalidate traditional techniques which model the physical layer in terms of simple collisions. Hence, these physical layer characteristics have been modelled and included in the analysis, which improves the level of agreements with simulated results.

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20

Wu, Qiyue. "Energy-Efficient Mobile Device-Assisted Schemes In Wireless Sensor Networks." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40466.

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Recently, wireless sensor networks (WSNs), consisted of battery-powered sensor nodes, are widely adopted by various civilian/military applications for implementing real-time monitoring or long-term surveillance tasks. One of the critical issues of WSNs is energy efficiency. Due to the limited battery capacity, the network lifetime and performance of WSNs are constrained. Also, once the sensor is deployed into a risky/remote environment, the replacement of its battery is hard. Therefore, how to improve the energy efficiency of the WSN is a critical issue and has gained tremendous attention from researchers around the world. To address this problem, by taking advantage of the emerging high-mobility devices (e.g., unmanned aerial vehicle (UAV)), we propose energy-efficient mobile device-assisted schemes in different-scale WSNs. Thanks to the rapid development of wireless techniques, two emerging approaches, i.e., data gathering technique and wireless charging technique, are beneficial to balance the workloads among all sensors or replenish energy to achieve the semi-permanent WSN. First, we design data gathering schemes using the mobile data collector. In order to meet the performance requirements of systems with different scales, our algorithms have two working modes: single- and multiple-data-collector scenarios. For the small-scale system, a single data collector is adopted to access and collect data from the deployed node, and we propose single mobile data collector-assisted (SDCA) data collection schemes for small-scale WSNs. For the large-scale system, multiple data collectors are utilized to gather sensed data from deployed nodes, and two-mode multiple mobile data collector-assisted (MDCA) data collection scheme is designed for balancing between the system energy consumption and the data forwarding latency. Second, the joint data collection and energy charging scheme is developed by adopting mobile chargers (MCs) as mobile devices that are responsible for energy charging and data collection simultaneously. For facing the different performance requirements of systems, a two-mode MC scheduling algorithm is presented. To evaluate our works, extensive simulation experiments are conducted on the OMNeT++ simulator. The results demonstrate that the proposed algorithms achieve better performance than the control group regarding system-wide energy efficiency, network lifetime and average end-to-end delay.

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Huang, Zheng, Takaya Yamazato, and Masaaki Katayama. "Energy Efficiency of Cooperative MISO Technique in Multi-hop Wireless Sensor Networks." IEEE, 2008. http://hdl.handle.net/2237/12137.

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Karvonen, H. (Heikki). "Energy efficiency improvements for wireless sensor networks by using cross-layer analysis." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526207506.

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Abstract This thesis proposes cross-layer approaches which enable to improve energy efficiency of wireless sensor networks and wireless body area networks (WSN & WBAN). The focus is on the physical (PHY) and medium access control (MAC) layers of communication protocol stack and exploiting their interdependencies. In the analysis of the PHY and MAC layers, their relevant characteristics are taken into account, and cross-layer models are developed to study the effect of these layers on energy efficiency. In addition, cross-layer analysis is applied at the network level by addressing hierarchical networks' energy efficiency. The objective is to improve energy efficiency by taking into account that substantial modifications to current standards and techniques are not required to take advantage of the proposed methods. The studied scenarios of WSN take advantage of the wake-up radio (WUR). A generic WUR-based MAC (GWR-MAC) protocol with objective to improve energy efficiency by avoiding idle listening is proposed. First, the proposed cross-layer model is developed at a general level and applied to study the forward error correction (FEC) code rate selection effect on the length of the transmission period and energy efficiency in a star topology network. Then an energy efficiency model for intelligent hierarchical architecture based on GWR-MAC is proposed and performance comparison with a duty-cycle radio (DCR) approach is performed. Interactions between different layers' devices are taken into account, and the WUR and DCR approaches are compared as a function of event frequency. The third cross-layer model focuses on the effect of the FEC code rate and data packet payload length on the energy efficiency of the IEEE Std 802.15.6-based WBANs using IR-UWB PHY. The results acquired by using analytical modelling and simulations with the Matlab software clearly illustrates the potential energy gains that can be achieved with the proposed cross-layer approaches. The developed WUR-based MAC protocol, analytical models and achieved results can be exploited by other researchers in the WSN and WBAN field. The contribution of this thesis is also to stimulate further research on these timely topics and foster development of short-range communication, which has a crucial role in future converging networks such as the Internet of Things Tiivistelmä Tässä väitöskirjassa ehdotetaan protokollakerrosten välistä tietoa hyödyntäviä (cross-layer) lähestymistapoja, jotka mahdollistavat energiatehokkuuden parantamisen langattomissa sensori- ja kehoverkoissa. Työ kohdistuu fyysisen- ja kanavanhallintakerroksen välisen vuorovaikutuksen tutkimiseen. Fyysisen- ja kanavanhallintakerrosten analyysissä huomioidaan niiden tärkeimmät ominaisuudet ja tutkitaan kerrosten yhteistä energiatehokkuutta. Lisäksi kerrosten välistä analyysiä sovelletaan verkkotasolle tutkimalla hierarkkisen verkon energiatehokkuutta. Tavoitteena on energiatehokkuuden parantamisen mahdollistaminen siten, että merkittäviä muutoksia nykyisiin standardeihin ja tekniikoihin ei tarvitse tehdä hyödyntääkseen ehdotettuja menetelmiä. Tutkitut sensoriverkkoskenaariot hyödyntävät heräteradiota. Väitöskirjassa ehdotetaan geneerinen heräteradiopohjainen kanavanhallintaprotokolla (GWR-MAC), jolla parannetaan energiatehokkuutta vähentämällä turhaa kanavan kuuntelua. Kerrosten välinen malli kehitetään ensin yleisellä tasolla ja sen avulla tutkitaan virheenkorjauskoodisuhteen valinnan vaikutusta lähetysperiodin pituuteen ja energiatehokkuuteen tähtitopologiaan pohjautuvissa sensoriverkoissa. Sitten väitöskirjassa ehdotetaan energiatehokkuusmalli älykkäälle GWR-MAC -protokollaan perustuvalle hierarkkiselle arkkitehtuurille ja sen suorituskykyä vertaillaan toimintajaksoperiaatteella toimivaan lähestymistapaan. Eri kerroksilla olevien laitteiden väliset vuorovaikutukset huomioidaan heräteradio- ja toimintajaksoperiaatteella toimivien verkkojen suorituskykyvertailussa tapahtumatiheyden funktiona. Kolmas malli kohdistuu virheenkorjauskoodisuhteen ja datapaketin hyötykuorman pituuden energiatehokkuusvaikutuksen tutkimiseen IEEE 802.15.6 -standardiin perustuvissa langattomissa kehoverkoissa. Analyyttinen mallinnus ja Matlab-ohjelmiston avulla tuotetut simulointitulokset osoittavat selvästi energiatehokkuushyödyt, jotka saavutetaan ehdotettuja menetelmiä käyttämällä. Kehitetty GWR-MAC -protokolla, analyyttiset mallit ja tulokset ovat hyödynnettävissä sensori- ja kehoverkkotutkijoiden toimesta. Tämän väitöskirjan tavoitteena on myös näiden ajankohtaisten aiheiden jatkotutkimuksen stimulointi sekä lyhyen kantaman viestinnän kehityksen vauhdittaminen, sillä niillä on erittäin merkittävä rooli tulevaisuuden yhteen liittyvissä verkoissa, kuten esineiden ja asioiden Internetissä

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Basich, Zoran Luka Josip. "MAC and physical layer energy efficiency for ad hoc wireless sensor networks." Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/14595.

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Includes bibliographical references (p. 102-103). The research work undertaken involves the design of a new, energy efficient Medium Access Control (MAC) layer for Ad Hoc Wireless Sensor Networks (AHWSN). MAC solutions are either contention based or non-contention based. Energy inefficiencies in contention based MAC protocols suffered from collisions, overhearing, control overhead and idle listening. Non-contention based MAC protocols introduced TDMA I CDMA I FDMA that did not suffer from those problematic issues. However, they suffered from other problems, such as energy inefficient hierarchies. The hierarchy uses cluster-heads to co-ordinate neighbours which is a continual requires that is energy inefficient. The proposal named Colour TDMA MAC is introduced, which does not have a hierarchy or cluster-head problems. It uses a single channel and simple transmitters. It also uses a distributed algorithm from colouring graph mathematics to ensure that the hidden terminal and exposed terminal problems of wireless data communication do not occur. Colour TDMA MAC also introduces the two concepts that allow nodes to sleep longer. The two are: * The Timed PicoRadio * The Mailbox. A node may sleep when it is not using the channel. Yet it may use one of the above concepts to receive a message destined for it. In the case of the timed PicoRadio, the node is awakened if it is sleeping. In the case of the mailbox, the radio signal is stored in memory and when the microprocessor awakens, it can deal with the message. A comparison of the central idea (Colour TDMA MAC) to a mainstream contention based MAC protocol (S-MAC) for AHWSN reveals that S-MAC suffers from collisions and idle listening (to a great extent) which is energy wasted. Its other energy inefficiencies are overhearing and control overhead. The two scheduling algorithms are compared via timing diagrams to see which delivers a message successfully in the shortest time. They are also placed head to head in some random tests to evaluate which is more energy efficient. Research work shows that the Colour TDMA MAC greatly improves energy savings. On the downside, it trades off energy for channel usage, thus messages take longer to reach their destination. Results also show that the Colour TDMA MAC is exceptionally good for unicast messaging where both the sender and the destination are known.

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Yilmaz, Mine. "Duty Cycle Control In Wireless Sensor Networks." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608856/index.pdf.

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Recent advances in wireless communication and micro-electro-mechanical systems (MEMS) have led to the development of implementation of low-cost, low power, multifunctional sensor nodes. These sensor node are small in size and communicate untethered in short distances. The nodes in sensor networks have limited battery power and it is not feasible or possible to recharge or replace the batteries, therefore power consumption should be minimized so that overall network lifetime will be increased. In order to minimize power consumed during idle listening, some nodes, which can be considered redundant, can be put to sleep. In this thesis study, basic routing algorithms and duty cycle control algorithms for WSNs in the literature are studied. One of the duty cycle control algorithms, Role Alternating, Coverage Preserving, and Coordinated Sleep algorithm (RACP) is examined and simulated using the ns2 simulation environment. A novel duty cycle control algorithm, Sink Initiated Path Formation (SIPF) is proposed and compared to RACP in terms of sleep sensor ratio and time averaged coverage.

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Koskela, P. (Pekka). "Energy-efficient solutions for wireless sensor networks." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526217611.

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Abstract Wireless sensors play a bigger and bigger role in our everyday life and they have become a part of our life in homes, vehicles, traffic, food production and healthcare, monitoring and controlling our activities. Low-cost and resource-efficient solutions are an essential part of this development. The aim of the study was to develop solutions, which improve the energy efficiency of wireless sensor networks yet still fulfil the requirements of monitoring applications. In the study, five new solutions were developed to save energy in wireless sensor networks and all the solutions were studied and verified with test bed implementations. The developed solutions are: 1. Energy-efficient medium access control (MAC), namely revive MAC (R-MAC) for duty-cycling networks with a long sampling interval (many minutes) 2. Wake-up radio solution for on-demand sampling networks, which uses the main radio as the wake-up transmitter 3. Energy-efficient internet of things (IoT) routing solution for wake-up routing with a routing protocol for low-Power and lossy networks (RPL) 4. Energy-efficient IoT compression solution: robust header compression (ROHC) compression with constrained application protocol (CoAP) 5. Data analysis solution based on an energy-efficient sensor node, where filter clogging is forecast from analysis of the vibration data at the node. All the developed solutions were promising and can be utilized in many domain areas. The solutions can be considered as proofs of concept, which need to be developed further for use in final products Tiivistelmä Langattomat sensoreilla on yhä suurempi osuus jokapäiväisessä arjessa, jossa langattomat sensorit ovat tulleet osaksi kodin, autojen, ruuantuotannon sekä terveyden valvonta- ja seurantajärjestelmiä. Oleellisena osana tätä kehitystä ovat sekä edulliset että energia- ja resurssitehokkaat ratkaisut. Työn päämääränä oli kehittää ratkaisuja, jotka parantavat langattoman sensoriverkon energia tehokkuutta niin, että edelleen täytetään monitorointi sovellutusten asettamat vaatimukset. Työssä kehitettiin viisi uutta ratkaisua säästää energiaa langattomissa sensoriverkoissa ja kaikki ratkaisut tutkittiin ja varmennetiin työssä tehdyillä testi alustoilla. Kehitetyt ratkaisut ovat: 1. Energiatehokas alempi siirtoyhteyskerroksen protokolla (medium access control, MAC), nimittäin heräävä MAC (Revive MAC, R-MAC) jaksoittain toimiville (duty-cycling) verkoille, joissa on pitkät mittausvälit (useita minuutteja). 2. Heräteradioratkaisu (wake-up) pyynnöstä toimiville (on-demand) verkoille, joissa pääradiota käytetään heräte signaalin lähettämiseen. 3. Energiatehokas esineiden internetin (Internet of Things, IoT) reititysratkaisu herätereititykseen käyttäen matalatehoisille ja häviöllisille verkoille suunniteltua reititysprotokollaa (Routing protocol for low-Power and Lossy networks, RPL). 4. Energiatehokas IoT-pakkausratkaisu: varmatoiminen otsakkeen pakkausprotokolla (Robust Header Compression, ROHC) yhdessä rajoitettujen sovellusten protokollan (Constrained Application Protocol, CoAP) kanssa. 5. Energiatehokas sensorilaite perusteinen data prosessointi ratkaisu suodattimen tukkeutumisen ennustamiseen värähtelymittauksia käyttäen. Kaikki kehitetyt ratkaisut olivat lupaavia ja niitä voidaan käyttää useilla sovellutusalueilla. Ratkaisut ovat soveltuvuusselvityksiä (proof of concept), joita pitää kehittää edelleen loppu tuotteiden käyttöön

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Raghuwanshi, Srajan Singh. "An Energy Efficient Cross Layer Design Scheme for Wireless Sensor Networks." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/35385.

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Wireless Sensor Networks (WSNs) are wireless networks that have recently drawn significant research attention since they offer unique benefits and versatility with respect to sensing, allowing low-power and low-cost rapid deployment for many applications that do not need human supervision. WSNs are self-created and self-organized by the collection of a large number of sensor nodes interconnected by multi-hop wireless paths. The sensor nodes are network embedded systems with Integrated Chips (ICs) to allow signal processing and micro-sensing. Each wireless sensor node is a micro-electro-mechanical device and can only be equipped with a limited power reserve. While energy consumption occurs in sensing, data processing and communications, care should be exercised to make the most of the expendable power source for the node. Though considerable research is being done in the area of energy saving techniques for WSNs, most of the proposed techniques have focused on energy awareness at different network layers in WSNs. Furthermore, most of the proposed techniques are based on protocols for mobile ad hoc networks that do not look into the possibility of a cross-layer design strategy that can exploit the unique features of WSNs. There still exists the need for a universal protocol that can be applied to such networks in general. In this thesis, we focus such a research on optimizing the energy consumption by suggesting a novel cross-layer architecture at the network/data-link layer for sensor networks. We have developed a scheme for better and improved energy efficiency in WSNs by combining the ideas of energy-efficient cluster formation and medium access together. Our cross-layer scheme provides good performance in terms of WSN-lifetime, scalability and minimizing network-wide energy consumption. The scheme is based on a collaborative approach supported by formation of dynamic clusters functioning with a traffic aware MAC (medium access control) scheme. Our MAC scheme incorporates a self-learning, traffic adaptive algorithm for varying traffic conditions inherent to the WSNs. The design methodology and results in this thesis aim at producing a reliable and scalable energy-aware sensing network, in spite of node failures, minimizing energy consumption at the same time. Master of Science

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Liu, Sha. "ENERGY EFFICIENT MAC LAYER DESIGN FOR WIRELESS SENSOR NETWORKS." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211909954.

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Vincent, Patrick J. "Energy conservation in wireless sensor networks." Monterey, California. Naval Postgraduate School, 2007, 2007. http://hdl.handle.net/10945/10228.

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This dissertation presents a system-level approach for minimizing the power expended in achieving communication between a ground-based sensor network and an overhead Unmanned Aerial Vehicle (UAV). A subset of sensor nodes, termed a transmit cluster, aggregates data gathered by the network and forms a distributed antenna array, concentrating the radiated transmission into a beam aimed towards the UAV. We present a method for more uniformly distributing the energy burden across the sensor network, specifying the time that should elapse between reassignments of the transmit cluster and the number of hops that should be placed between successive transmit clusters. We analyze the performance of two strategies for reconfiguring the communication burden between the sensor network and the UAV in order to bring the UAV and the sensor network's beam into alignment quickly, while minimizing the energy expenditure. We analyze the optimal number of nodes that should participate in a beamforming process in order to minimize the energy expended by the network, and we provide a framework to analyze the minimum energy expended in a simple beamforming algorithm. Finally, we analyze the probability that an arbitrarily selected sensor node is connected to a specified number of other nodes and we present an algorithm for the formation of near-linear arrays given random placement of nodes.

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Persson, Erik. "Energy Harvesting in Wireless Sensor Networks." Thesis, Uppsala universitet, Signaler och System, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388006.

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Over the past few years, the interest of remote wireless sensor networks has increased with the growth of Internet of Things technology. The wireless sensor network applications vary from tracking animal movement to controlling small electrical devices. Wireless sensors deployed in remote areas where the grid is unavailable are normally powered by batteries, inducing a limited lifespan for the sensor. This thesis work presents a solution to implement solar energy harvesting to a wireless sensor network. By gathering energy from the environment and using it in conjunction with an energy storage, the lifetime of a sensor node can be extended while at the same time reducing maintenance costs. To make sensor nodes in a network energy efficient, an adaptive controller of the nodes energy consumption can be used. A network consisting of a client node and a server node was created. The client node was powered by a small solar cell in conjunction with a capacitor. A linear-quadratic tracking algorithm was implemented to adaptively change the transmission rate for a node based on its current and previous battery level and the energy harvesting model. The implementation was done using only integers. To evaluate the system for extended run-times, the battery level was simulated using MATLAB. The system was simulated for different weather conditions. The simulation results show that the system is viable for both cloudy and sunny weather conditions. The integer linear-quadratic algorithm responds to change very abruptly in comparison to a floating point-version.

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Li, Wei, and Zhiyuan Guo. "On Forward Error Correction in IEEE 802.15.4 Wireless Sensor Networks." Thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-16614.

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Wireless Sensor Networks (WSN) are used in many applications, for example industrial applications, automatic control applications, monitoring applications, to name but a few. Although WSN can employ different standards in order to achieve short range wireless communication, the mainstream of the market is toadopt the low-power, low-rate IEEE 802.15.4 standard. However, this standard does not specify any block codes on the Physical layer (PHY) and the MAC sublayer. Reliability and energy efficiency are two important metrics used to evaluate the WSN performance. In order to enhance the reliability of the WSN performance, schemes such as Forward Error Correction (FEC) and HybridAutomatic Repeat-reQuest (HARQ) can be introduced on the PHY and MACsublayer when transmitting signals. However, this will reduce the energy efficiency of the WSN. In order to investigate what does affect the reliability and energy efficiency, this thesis has been conducted with the assistance of Matlab simulations, which simulate different transmission schemes proposed by the authors. Based on the simulations, both the reliability and energy efficiency can be evaluated and the results are illustrated for both metrics. The objective of this thesis is to determine a scheme that is able to meet these metric requirements.

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WANG, XIAODONG. "QoS ISSUES AND QoS CONSTRAINED DESIGN OF WIRELESS SENSOR NETWORKS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1144634884.

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ANTONY, SAJI M. "DESIGN OF ENERGY EFFICIENT TRANSCEIVER BLOCKS FOR WIRELESS SENSOR NODES." Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2020. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18771.

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Sensor networks have been recognised as one of the most advanced technologies of the 21st century with vast practical applications. The life of a sensor network is mainly determined by its energy consumption. Commercially available sensor nodes are battery driven devices. As most sensor nodes are deployed widely scattered and in isolated areas, replacing battery is not an option. This dissertation focuses on extending the lifespan of sensor networks by reducing energy consumption in design and operation of sensor nodes. The study goes in depth to analyse the state of art technology to achieve energy efficiency in sensor nodes and identify scope for further research in this field. In the architecture of sensor nodes, multipliers are the main blocks for designing an energy efficient processor. Vedic Mathematics provides principles of high speed multiplication. The main reason for power dissipation in multiplier circuit is due to power dissipation of full adder circuit. Low power multipliers have been designed by using low power adders. Motivated by this, a high speed Vedic multiplier has been designed using multiplexer based adder. When compared with existing Vedic multipliers, proposed designs showed significant improvement in reduction of delay and energy consumption. Sensor nodes consume maximum power during data communication. So processing data locally at each node in a sensor network is important for minimizing power consumption. High processing speed and low area designs are in ever growing demand. In order to predict outcomes, based on previous inputs, ALU can be designed with neurons. Processing speed of ALU can be improved by replacing conventional multipliers with Vedic multipliers. This research work suggests implementation of high speed ALU using Vedic neurons. The analysis of the results shows that the proposed design leads to x reduction in the delay and reduction in LUT count (an indicator of area) of the ALU. Use of energy efficient power amplifiers is an essential requirement for sensor nodes, as power amplifiers are responsible for the main power consumption in the transceivers of sensor nodes. Again, wider band width is another important requirement for power amplifiers used in sensor transceivers especially in wireless visual sensor networks and wireless multimedia sensor networks. Reliability of a power amplifier can be increased by designing it at smaller supply voltage. This thesis suggests improvements in design of power amplifier in class E configuration, for transceivers in wireless sensor nodes. In order to achieve wider band width, cascade of common drain followed by common source in class E configuration has been designed; and for more reliable operation with higher efficiency, class E in double cascoded has been implemented. The proposed designs, when simulated in SPICE, higher efficiencies and band widths have been achieved. This research also explored to design a robust solar energy harvesting system to enhance life time of sensor nodes. Proposed solar energy supply system mainly consists of a solar panel, rechargeable battery and a control circuit. To obtain sufficient voltage to charge battery, electrical energy generated through panel is boosted by boost converter. Different sensor nodes are supplied with energy from this system. An inverter is also designed for AC applications. Experimental results show that this compact, self-sufficient system enables outdoor based wireless sensor network nodes to operate successfully for longer periods.

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Angelopoulos, Georgios Ph D. Massachusetts Institute of Technology. "Improving the energy efficiency and reliability of wireless sensor networks using coding techniques." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103716.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016. Cataloged from PDF version of thesis. Includes bibliographical references (pages 129-145). Wireless sensor networks (WSNs) are rapidly being adopted in a wide range of applications, from continuous health monitoring to automated industrial infrastructures, and soon will have a major environmental, financial and societal impact. Some of the main technical challenges in designing and deploying WSNs are meeting their communications reliability and energy consumption requirements. In order to address these two challenges, this thesis proposes new coding schemes and communication protocols, a novel paradigm for information acquisition, and the design and implementation of specific, circuits architectures. The reliability and energy efficiency trade-offs of splitting the inserted redundancy in multiple layers of the network stack are investigated through analysis and over-the-air experiments. Not only appropriate and efficient coding schemes for each layer are examined, but their interaction and synergistic functioning are explored. The energy benefits of each approach are quantified by designing a low-power custom transmitter using a 65nm TSMC process, integrating the first hardware implementation of a multi-rate forward error correction (FEC) and random linear network coding (RLNC) accelerator. In addition, a physical layer (PHY) independent partial packet reception (PPR) scheme is proposed for asymmetric networks, i.e. WSNs with a star topology, called packetized rateless algebraic consistency (PRAC). PRAC reduces the number of retransmissions by harnessing information contained in partial packets. Experiments with off-the-shelf transceivers validate our analysis results on the data reliability and energy consumption benefits of the proposed scheme. Apart from communicating information, acquiring the signals of interest can account for a significant fraction of the power consumption of a sensor node. For this reason, the thesis proposes a nonuniform sampling scheme in order to exploit the inherent compressibility and sparse structure of typical signals encountered in many WSNs. Simulations results with real datasets and an energy comparison against the state-of-the-art sampling schemes demonstrate its rate and energy efficiency advantages. Finally, the thesis studies the joint fundamental performance bounds of acquiring and transmitting sparse signals through noisy channels. An integrated source representation-to-transmission scheme, called AdaptCast, is proposed and, using rate distortion analysis, its asymptotically optimal performance is proved. Based on simulation results in the context of a health monitoring application, AdaptCast's performance benefits are demonstrated against other coding schemes and PHY architectures in terms of the provided data reliability and reconstruction distortion. by Georgios Angelopoulos. Ph. D.

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Amdouni, Ichrak. "Wireless Self-adaptive Ad hoc and Sensor Networks : Energy Efficiency and Spatial Reuse." Paris 6, 2013. http://www.theses.fr/2013PA066003.

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La nécessité de maximiser la durée de vie du réseau sans fil dans les réseaux ad hoc et en particulier dans les réseaux de capteurs sans fil nécessite l'utilisation d'algorithmes d'efficacité énergétique. Motivée par le fait qu'un noeud consomme le moins d'énergie lorsqu’il est en veille, nous réalisons l'efficacité énergétique vi des algorithmes d'ordonnancement des activités des noeuds. Les noeuds reçoivent des slots temporels durant lesquels ils peuvent transmettre et ils peuvent éteindre leur radio quand ils ne sont ni en train de transmettre, ni en train de recevoir. Par rapport au TDMA classique, l’utilisation de la bande passante est optimisée: deux noeuds interférents ne partagent pas les mêmes slots. Dans notre travail sur l’ordonnancement, deux cas sont étudiés. Tout d'abord, lorsque les nœuds nécessitent le même temps d’accès au canal, nous utilisons le coloriage des nœuds. Deuxièmement, lorsque les nœuds requièrent des débits hétérogènes, nous utilisons une allocation de slots « traffic aware ». Contrairement à la majorité des travaux antérieurs, nous généralisons la définition du coloriage des noeuds et les problèmes d'attribution des slots. En effet, nous considérons que la distance maximale entre deux nœuds interférents est un paramètre de ces problèmes. Nous prouvons qu'ils sont NP-complets, ce qui rend inévitable l’utilisation des heuristiques dans la pratique. Une directive centrale de cette thèse est de concevoir des solutions auto-adaptatives. Cette adaptabilité concerne de nombreux aspects tels que la mission confiée par l'application, l'hétérogénéité des demandes de trafic de nœuds, la densité du réseau, de la régularité de la topologie du réseau, et la non fiabilité des liens sans fil The need to maximize network lifetime in wireless ad hoc networks and especially in wireless sensor networks requires the use of energy efficient algorithms and protocols. Motivated by the fact that a node consumes the least energy when its radio is in sleep state, we achieveenergy efficiency by scheduling nodes activity. Nodes are assigned time slots during which they can transmit and they can turn off their radio when they are neither transmitting nor receiving. Compared to classical TDMA-based medium access scheme, spatial bandwidth use is optimized: non interfering nodes are able to share the same time slots, collisions are avoided and overhearing and interferences are reduced. In our work about time slots assignment, two cases are studied. First, when nodes require equal channel access, we use node coloring. Second, when nodes have heterogeneous traffic demands, we designed the traffic aware time slot assignment algorithm TRASA. Unlike the majority of previous works, we generalize the definition of node coloring and slot allocation problems. Indeed, we set the maximum distance between two interfering nodes as a parameter of these problems. We prove that they are NP-complete, making heuristic approaches inevitable in practice. A central directive of this thesis is to design self-adaptive solutions. This adaptivity concerns many aspects such as the mission given by the application, the heterogeneity of nnode traffic demands, the network density, the regularity of network topology, and the failure of wirelesslinks

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Jayachandran, Krishna K. "STBC-encoded cooperative asynchronous transmissions for transmission energy efficiency." Diss., Online access via UMI:, 2005.

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Hansen, Ewa. "Centralized Routing for Prolonged Network Lifetime in Wireless Sensor Networks." Licentiate thesis, Västerås : School of Innovation, Design and Engineering, Mälardalen University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-486.

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Tönsing, Christoph Erik. "Energy -efficient MAC protocol for wireless sensor networks." Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-09042008-143948/.

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JAWAD, ALI SYED, and PARTHA ROY. "Energy Saving Methods in Wireless Sensor Networks." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1437.

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To predict the lifetime of wireless sensor networks before their installation is an important concern. The IEEE 802.15.4 standard is specifically meant to support long battery life time; still there are some precautions to be taken by which a sensor network system application based on the standard can be made to run for longer time periods.This thesis defines a holistic approach to the problem of energy consumption in sensornetworks and suggests a choice of node architecture, network structure and routingalgorithm to support energy saving in the network. The idea and thrust of the thesis is that stand-alone measures such as selecting a low-power microcontroller with embedded transceiver will not alone be sufficient to achieve energy saving over the entire network. A comprehensive design study with energy saving as a primary task must be made. Focus given on the design objectives needs to look at different aspects – application code, network configuration code, routing algorithms etc to come up with an energy efficient network.

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Srivastava, Rahul. "Efficient Energy Management in Wireless Sensor Networks." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1290622805.

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40

Didioui, Amine. "Energy-aware transceiver for energy harvesting wireless sensor networks." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S056/document.

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Les progrès technologiques accomplis durant ces dernières décennies dans les domaines des microsystèmes et des radiocommunications nous permettent de réaliser des composants communicants miniaturisés à faible coût afin de constituer des réseaux de capteurs sans fil. Typiquement, chacun de ces composants intègre une ou plusieurs unités de mesures (capteur), une unité de traitement de données, une unité de communication radio et une batterie. De ce fait, un nouveau domaine de recherche s’est créé pour étudier le déploiement de ces réseaux afin d’offrir des solutions de surveillance et de contrôle à distance, notamment dans des environnements complexes ou inaccessibles. Les domaines d’application de ces capteurs sont très variés, allant de la domotique au militaire en passant par le médical et les infrastructures civiles. Souvent, ces applications impliquent des contraintes sévères en terme d’autonomie qui idéalement devrait atteindre plusieurs dizaines d’années. Pour atteindre cet objectif, il est à la fois nécessaire de réduire la consommation énergétique du nœud capteur et de trouver d’autres solutions d’alimentation en énergie pour le nœud. Pour adresser ce deuxième point, la récupération d’énergie à partir de l’environnement (solaire, vibratoire, thermique, etc.) semble représenter une solution idéale pour alimenter un nœud capteur, bien que celui-ci doive s’adapter aux faibles quantités d’énergie récupérées par ces systèmes, ainsi qu’à leurs variations et intermittences. Ces travaux de thèse s’intéressent donc à la problématique de la simulation et de la réduction de la consommation des nœuds de capteurs sans-fil et autonomes en énergie. Dans un premier temps, nous avons développé la plateforme HarvWSNet, un environnement de co-simulation alliant le simulateur de réseaux WSNet et Matlab permettant ainsi la modélisation précise et la simulation hétérogène des protocoles de communication (typiquement à événements discrets) et des systèmes de récupération d’énergie (qui possèdent typiquement un comportement à temps continu). Nous avons démontré que cette plateforme permet de réaliser très rapidement des études de pré-prototypage de scénarios applicatifs de déploiement et ainsi réduire le temps de conception de ces nouvelles technologies. Grâce à la modélisation précise des éléments du système de récupération d’énergie (batterie, supercapacité, etc.) permise par cette plateforme, nous avons étudié et évalué la durée de vie de déploiements à large échelle de réseaux de capteurs alimentés par des systèmes de récupération d’énergie (solaire et éolien). La deuxième contribution de cette thèse concerne l’étude et l’implémentation de stratégies de reconfiguration dans l’interface de communication radio, qui est souvent la principale source de consommation d’énergie d’un capteur, afin de permettre au nœud et/ou au réseau de minimiser sa consommation lorsque le bilan de liaison RF est favorable. A cette fin, nous avons proposé une approche originale grâce au développement d’un simulateur de réseau dédié, EnvAdapt (basé sur WSNet). Dans cette nouvelle plateforme, des modèles de consommation des différents blocs du transceiver radio et des algorithmes de reconﬁguration ont été implémentés aﬁn d’étudier l’impact de la reconﬁguration des performances de la radio sur la qualité de service et l’autonomie d’un réseau de capteurs Technological advances achieved over the past decade in the fields of microsystems and wireless communications have enabled the development of small size and low cost sensor nodes equipped with wireless communication capabilities able to establish a wireless sensor network (WSN). Each sensor node is typically equipped with one or several sensing unit, a data processing unit, a wireless communication interface and a battery. The challenges raised by WSNs has lead to the emergence of a new research domain which focuses on the study and deployment of such a networks in order to offer the required remote monitoring and control solutions for complex and unreachable environment. WSNs have found application in a wide range of different domains, including home and structural health monitoring, military surveillance, and biomedical health monitoring. These applications usually impose stringent constraints on the WSN lifetime which is expected to last several years. To reach this objective, it is necessary to reduce the overall energy consumption of the sensor node and to find an additional source of energy as well. To address the last point, energy harvesting from the environment seems to be a an efficient approach to sustain WSNs operations. However, energy harvesting devices, which must also be small, are usually unable to ensure a continuous operation of sensor nodes. Thus, it is necessary to adapt the WSN consumption and activity to the low and unpredictable energy scavenged. The work presented in this thesis focuses on the issue of simulation and power consumption of autonomous sensor nodes. We have first developed, HarvWSNet, a co-simulation framework combining WSNet and Matlab that provides adequate tools to accurately simulate heterogenous protocols (based on discrete-time events) and energy harvesting systems (based on continuous-time events). We have demonstrated that HarvWSNet allows a rapid evaluation of energy-harvesting WSNs deployment scenarios that may accelerate the time-to-market for these systems. Thanks to the accurate energy models (battery, supercapacitor, etc.) implemented in this platform, we have studied and evaluated a large scale deployment of solar and wind energy-harvesting WSNs. Our second contribution focuses on the implementation of energy-aware reconfiguration strategies in the radio transceiver which is usually considered as the most energy hungry component in a sensor node. These strategies are intended to reduce the excessive power consumption of the radio transceiver when the channel conditions are favorable. To this end, we have a new simulation framework called EnvAdapt (based also on WSNet) dedicated to the evaluation of reconfigurable radio transceivers for WSNs. In EnvAdapt, we have implemented the required radio transceiver behavioral and power consumption models that allows the evaluation of the impact of radio transceiver reconfiguration on the communication performance and lifetime of WSNs

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41

Raza, Usman. "From Energy Efficient to Energy Neutral Wireless Sensor Networks." Doctoral thesis, Università degli studi di Trento, 2015. https://hdl.handle.net/11572/368652.

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Energy autonomy for Wireless Sensor Networks (WSNs) is a key to involve industry stakeholders willing to spend billions on the Internet of Things. By offering the lifetime of only a few years, traditional battery powered WSNs are neither practical nor profitable due to their high maintenance cost. Powering WSNs with energy harvesters can overcome this limitation and increase mean time-to-maintenance to tens of years. However, the primary challenge in realizing an energy neutral operation is to reduce the consumed energy drastically to match with the harvested energy. This dissertation proposes techniques to minimize the overhead of two main activities: communication and sampling. It does so by making a key observation: a plethora of applications can accept low accuracy of sensed phenomenon without sacrificing the application requirements. This fact enables us to reduce consumed energy by radically revising the network stack design, all the way from the application layer to underlying hardware. At the application layer, the relaxed requirements make it possible to propose techniques to reduce the data exchanges among the nodes, the most power hungry operation in WSNs. For example, we propose a simple yet efficient prediction based data collection technique called Derivative-Based Prediction (DBP) that enables data suppression up to 99%. With the remaining ultra-low application data rate, a full system-wide evaluation reveals that the dominating overhead of the lower layers greatly limits the gains enabled by DBP. A cross-layer optimization of the network stack is then designed specifically to strip off the unnecessary overhead to gain one order of magnitude longer lifetime. Although a huge saving in relative terms, the resulting power consumption is still much higher than tens of microwatts, the power usually achievable from a reasonably sized harvester deployed in an indoor environment. Therefore, we consider a novel combination of hardware components to further reduce power consumption. Our work demonstrates that using wake-up receivers along with DBP results in long idle periods with only rare occurrences of power hungry states such as radio transmissions and receptions. Low power modes, provided by various components of the underlying hardware platform, are adopted in the idle periods to conserve energy. In concrete real-world case studies, the lifetime is estimated to improve by two orders of magnitude. Thanks to the software and hardware features proposed above, the overall power consumption is reduced to a point where the sampling cost constitutes a significant portion of it. To reduce the cost of sampling, we introduce the concept of Model-based Sensing in which we push prediction based data collection as close as possible to the hardware sensing elements. This hardware-software co-design results in a system that consumes only a few microwatts, a point where even harvesters deployed in challenging indoor conditions can sustain the operation of nodes. This dissertation advances the state of art on energy efficient WSNs in several dimensions. First, it bridges the gap between theory and practice by providing the first ever system-wide evaluation of prediction based data collection in real-world WSNs. Second, new software based optimizations and novel hardware components are proposed that can deliver three orders of magnitude reduction in power consumption. Third, it provides tools to estimate the harvestable energy in real WSNs. By using these tools, the work highlights that the energy consumed by the proposed mechanisms is indeed lower than the energy harvested. By closing the gap between supply and demand of energy, the dissertation takes a concrete step in the direction of achieving completely energy neutral WSNs.

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42

Raza, Usman. "From Energy Efficient to Energy Neutral Wireless Sensor Networks." Doctoral thesis, University of Trento, 2015. http://eprints-phd.biblio.unitn.it/1533/1/PhD-Thesis.pdf.

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Energy autonomy for Wireless Sensor Networks (WSNs) is a key to involve industry stakeholders willing to spend billions on the Internet of Things. By offering the lifetime of only a few years, traditional battery powered WSNs are neither practical nor profitable due to their high maintenance cost. Powering WSNs with energy harvesters can overcome this limitation and increase mean time-to-maintenance to tens of years. However, the primary challenge in realizing an energy neutral operation is to reduce the consumed energy drastically to match with the harvested energy. This dissertation proposes techniques to minimize the overhead of two main activities: communication and sampling. It does so by making a key observation: a plethora of applications can accept low accuracy of sensed phenomenon without sacrificing the application requirements. This fact enables us to reduce consumed energy by radically revising the network stack design, all the way from the application layer to underlying hardware. At the application layer, the relaxed requirements make it possible to propose techniques to reduce the data exchanges among the nodes, the most power hungry operation in WSNs. For example, we propose a simple yet efficient prediction based data collection technique called Derivative-Based Prediction (DBP) that enables data suppression up to 99%. With the remaining ultra-low application data rate, a full system-wide evaluation reveals that the dominating overhead of the lower layers greatly limits the gains enabled by DBP. A cross-layer optimization of the network stack is then designed specifically to strip off the unnecessary overhead to gain one order of magnitude longer lifetime. Although a huge saving in relative terms, the resulting power consumption is still much higher than tens of microwatts, the power usually achievable from a reasonably sized harvester deployed in an indoor environment. Therefore, we consider a novel combination of hardware components to further reduce power consumption. Our work demonstrates that using wake-up receivers along with DBP results in long idle periods with only rare occurrences of power hungry states such as radio transmissions and receptions. Low power modes, provided by various components of the underlying hardware platform, are adopted in the idle periods to conserve energy. In concrete real-world case studies, the lifetime is estimated to improve by two orders of magnitude. Thanks to the software and hardware features proposed above, the overall power consumption is reduced to a point where the sampling cost constitutes a significant portion of it. To reduce the cost of sampling, we introduce the concept of Model-based Sensing in which we push prediction based data collection as close as possible to the hardware sensing elements. This hardware-software co-design results in a system that consumes only a few microwatts, a point where even harvesters deployed in challenging indoor conditions can sustain the operation of nodes. This dissertation advances the state of art on energy efficient WSNs in several dimensions. First, it bridges the gap between theory and practice by providing the first ever system-wide evaluation of prediction based data collection in real-world WSNs. Second, new software based optimizations and novel hardware components are proposed that can deliver three orders of magnitude reduction in power consumption. Third, it provides tools to estimate the harvestable energy in real WSNs. By using these tools, the work highlights that the energy consumed by the proposed mechanisms is indeed lower than the energy harvested. By closing the gap between supply and demand of energy, the dissertation takes a concrete step in the direction of achieving completely energy neutral WSNs.

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Rimer, Suvendi Chinnappen. "Energy efficient communication models in wireless sensor and actor networks." Thesis, University of Pretoria, 2012. http://hdl.handle.net/2263/23253.

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Sensor nodes in a wireless sensor network (WSN) have a small, non-rechargeable power supply. Each message transmission or reception depletes a sensor node’s energy. Many WSN applications are ad-hoc deployments where a sensor node is only aware of its immediate neighbours. The lack of a predefined route path and the need to restrict the amount of communication that occurs within the application area impose constraints on WSNs not prevalent in other types of networks. An area of active research has been how to notify the central sink (or monitoring hub) about an event in real-time by utilising the minimum number of messages to route a message from a source node to the destination sink node. In this thesis, strategies to limit communication within a WSN application area, while ensuring that events are reported on and responded to in real-time, is presented. A solution based on modelling a WSN as a small world network and then transmitting an initialisation message (IM) on network start-up to create multiple route paths from any sensor node to one or more sinks is proposed. The reason for modelling a WSN as a small world network is to reduce the number of nodes required to re-transmit a message from a source sensor node to a sink. The purpose of sending an IM at network start-up is to ensure that communication within the WSN is minimised. When routing a message to a static sink, the nodes closest to the static sink receive a disproportionate number of messages, resulting in their energy being consumed earlier. The use of mobile sinks has been proposed but to our knowledge no studies have been undertaken on the paths these mobile sinks should follow. An algorithm to determine the optimum path for mobile sinks to follow in a WSN application area is described. The purpose of an optimum path is to allow more equitable usage of all nodes to transfer an event message to a mobile sink. The idea of using multiple static sinks placed at specific points in the small world model is broadened to include using multiple mobile sinks called actors to move within a WSN application area and respond to an event in real-time. Current coordination solutions to determine which actor(s) must respond to the event result in excessive message communication and limit the real-time response to an event. An info gap decision theory (IGDT) model to coordinate which actor or set of actors should respond to the event is described. A comparison of the small world routing (SWR) model against routing using flooding and gossiping shows that the SWR model significantly reduces the number of messages transmitted within the network. An analysis of the number of IMs transmitted and received at individual node level shows that prudent selection of the hop count (number of additional nodes required to route a message to sink) to a sink node will result in a reduced number of messages transmitted and received per node within the network. The use of the IGDT model results in a robust decision on the actor(s) chosen to respond to an event even when uncertainty about the location and available energy of other actor(s) exists. Thesis (PhD(Eng))--University of Pretoria, 2012. Electrical, Electronic and Computer Engineering unrestricted

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Vedantham, Ramanuja. "Energy-Efficient Network Protocols for Wireless Sensor and Actor Networks." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13959.

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Wireless sensor networks (WSNs) have a wide variety of applications in civilian, medical and military applications. However, the nodes in such a network are limited to one type of action: sensing the environment. With increasing requirements for intelligent interaction with the environment, there is a need to not only perceive but also control the monitored environment. This has led to the emergence of a new class of networks, referred to as wireless sensor and actor networks (WSANs), capable of performing both sensing and acting tasks on the environment. The evolution from WSNs, which can be thought of as performing only read operations, to WSANs, which can perform both read and write operations, introduces unique and new challenges that need to be addressed. In this research, the fundamental challenges required for effective operation of WSANs are analyzed from the following three different perspectives: (i) operation correctness, (ii) resource optimality, and (iii) operation performance. The solutions proposed to address the challenges are evaluated with the optimal solution and other competing approaches through analytical and simulation results. The feasibility of the proposed solutions is demonstrated through a testbed implementation.

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Ghneimat, Ahmed A. H. "Adaptive technique for energy management in wireless sensor networks. Development, simulation and evaluation of adaptive techniques for energy efficient routing protocols applied to cluster based wireless sensor networks." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5751.

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Recently, wireless sensor networks have become one of the most exciting areas for research and development. However, sensor nodes are battery operated, thus the sensor¿s ability to perform its assigned tasks is limited by its battery capacity; therefore, energy efficiency is considered to be a key issue in designing WSN applications. Clustering has emerged as a useful mechanism for trade-off between certain design goal conflicts; the network life time, and the amount of data obtained. However, different sources of energy waste still exist. Furthermore, in such dynamic environments, different data rate requirements emerge due to the current network status, thus adapting a response to the changing network is essential, rather than following the same principle during the network¿s lifespan. This thesis presents dynamic techniques to adapt to network changes, through which the limited critical energy source can be wisely managed so that the WSN application can achieve its intended design goals. Two approaches have been taken to decreasing the energy use. The first approach is to develop two dynamic round time controllers, called the minimum round time controller MIN-RC and the variable round time controller VAR-RC, whereas the second approach improves intra-cluster communication using a Co-Cluster head; both approaches show better energy utilisation compared to traditional protocols. A third approach has been to develop a general hybrid protocol H-RC that can adapt different applications requirements; it can also tolerate different data rate requirements for the same application during the system¿s lifetime.

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Biswas, Kamanashis. "Energy Efficient Secure Routing in Wireless Sensor Networks." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/365658.

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Wireless Sensor Networks (WSNs) can contain thousands of small, inexpensive sensors that are randomly deployed in open and harsh environments to collect data. The short lifespan of the battery-operated sensors and the hostile environments necessitate the development of energy ecient and secure protocols in sensor networks. Among the wide variety of network protocols, routing plays the most signicant role in energy consumption since 70% of the total energy is consumed for data transmission in WSNs. Therefore, it is necessary to design energy ecient routing schemes to conserve energy and prolong the network lifetime. However, resource limited sensors, lack of a global addressing scheme, and application-specic design of WSNs make routing a challenge. Furthermore, security is another critical issue in WSNs since sensors are generally deployed in unprotected environments and vulnerable to security attacks. The security algorithms have to be integrated with routing protocols to provide authenticity, condentiality, and integrity of transmitted data. Most of the existing routing protocols implement dierent security mechanisms to achieve the security goals. Any conflict among these measures may create vulnerabilities in the network. Therefore, to ensure energy eciency and minimisation of the implementation gap, energy ecient secure routing protocols have to be designed using a common security framework. Thesis (PhD Doctorate) Doctor of Philosophy (PhD) School of Information and Communication Technology Science, Environment, Engineering and Technology Full Text

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Yan, Shuo. "Energy-efficient Data Aggregation Using Realistic Delay Model in Wireless Sensor Networks." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20180.

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Data aggregation is an important technique in wireless sensor networks. The data are gathered together by data fusion routines along the routing path, which is called data-centralized routing. We propose a localized, Delay-bounded and Energy-efficient Data Aggregation framework(DEDA) based on the novel concept of DEsired Progress (DEP). This framework works under request-driven networks with realistic MAC layer protocols. It is based on localized minimal spanning tree (LMST) which is an energy-efficient structure. Besides the energy consideration, delay reliability is also considered by means of the DEP. A node’s DEP reflects its desired progress in LMST which should be largely satisfied. Hence, the LMST edges might be replaced by unit disk graph (UDG) edges which can progress further in LMST. The DEP metric is rooted on realistic degree-based delay model so that DEDA increases the delay reliability to a large extent compared to other hop-based algorithms. We also combine our DEDA framework with area coverage and localized connected dominating set algorithms to achieve two more resilient DEDA implementations: A-DEDA and AC-DEDA. The simulation results confirm that our original DEDA and its two enhanced variants save more energy and attain a higher delay reliability ratio than existing protocols.

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Ghneimat, Ahmed Ali Hassan. "Adaptive technique for energy management in wireless sensor networks : development, simulation and evaluation of adaptive techniques for energy efficient routing protocols applied to cluster based wireless sensor networks." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5751.

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Recently, wireless sensor networks have become one of the most exciting areas for research and development. However, sensor nodes are battery operated, thus the sensor's ability to perform its assigned tasks is limited by its battery capacity; therefore, energy efficiency is considered to be a key issue in designing WSN applications. Clustering has emerged as a useful mechanism for trade-off between certain design goal conflicts; the network life time, and the amount of data obtained. However, different sources of energy waste still exist. Furthermore, in such dynamic environments, different data rate requirements emerge due to the current network status, thus adapting a response to the changing network is essential, rather than following the same principle during the network's lifespan. This thesis presents dynamic techniques to adapt to network changes, through which the limited critical energy source can be wisely managed so that the WSN application can achieve its intended design goals. Two approaches have been taken to decreasing the energy use. The first approach is to develop two dynamic round time controllers, called the minimum round time controller MIN-RC and the variable round time controller VAR-RC, whereas the second approach improves intra-cluster communication using a Co-Cluster head; both approaches show better energy utilisation compared to traditional protocols. A third approach has been to develop a general hybrid protocol H-RC that can adapt different applications requirements; it can also tolerate different data rate requirements for the same application during the system's lifetime.

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Clark, Geoffrey Stuart Williamson. "Improving the energy efficiency and transmission reliability of battery-powered sensor nodes at the edges of a mains-powered wireless network." Thesis, University of Canterbury. Computer Science and Software Engineering, 2012. http://hdl.handle.net/10092/10033.

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A masters thesis focussing on achieving improvements in transmission reliability and energy efficiency for a battery-powered wireless sensor node on the edge of an industrial heterogeneous wireless network that consists predominantly of mains-powered nodes. A router-switching technique is proposed to allow the sensor node to make gains in transmission reliability and energy efficiency by taking advantage of the scenario where multiple wireless routers are in range and switching between them, instead of only being able to transmit to one router. The research involves simulation of a number of network scenarios where the router-switching technique is enabled and disabled, to measure the advantage gained for the sensor in terms of its functional lifetime. The simulation is based on an abstract model that focusses on the edge of the mains-powered area of the network, where the battery-powered sensor is located. The simulation results show that for many cases, router-switching provides a higher level of transmission reliability and lower levels of energy consumption than the scenario where router-switching is disabled, as well as improvements in data loss rates.

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Gong, P. "Energy efficient and secure wireless communications for wireless sensor networks." Thesis, City, University of London, 2017. http://openaccess.city.ac.uk/18026/.

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This dissertation considers wireless sensor networks (WSNs) operating in severe environments where energy efficiency and security are important factors. This main aim of this research is to improve routing protocols in WSNs to ensure efficient energy usage and protect against attacks (especially energy draining attacks) targeting WSNs. An enhancement of the existing AODV (Ad hoc On-Demand Distance Vector) routing protocol for energy efficiency, called AODV-Energy Harvesting Aware (AODVEHA), is proposed and evaluated. It not only inherits the advantages of AODV which are well suited to ad hoc networks, but also makes use of the energy harvesting capability of sensor nodes in the network. In addition to the investigation of energy efficiency, another routing protocol called Secure and Energy Aware Routing Protocol (ETARP) designed for energy efficiency and security of WSNs is presented. The key part of the ETARP is route selection based on utility theory, which is a novel approach to simultaneously factor energy efficiency and trustworthiness of routes in the routing protocol. Finally, this dissertation proposes a routing protocol to protect against a specific type of resource depletion attack called Vampire attacks. The proposed resource-conserving protection against energy draining (RCPED) protocol is independent of cryptographic methods, which brings advantage of less energy cost and hardware requirement. RCPED collaborates with existing routing protocols, detects abnormal sign of Vampire attacks and determines the possible attackers. Then routes are discovered and selected on the basis of maximum priority, where the priority that reflects the energy efficiency and safety level of route is calculated by means of Analytic Hierarchy Process (AHP). The proposed analytic model for the aforementioned routing solutions are verified by simulations. Simulations results validate the improvements of proposed routing approaches in terms of better energy efficiency and guarantee of security.

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