4 research outputs found
Planeación y despliegue de la red de sensores inalámbricos requerida para la medición inteligente de energía eléctrica usando restricciones de capacidad y cobertura
The electrical energy measurement (EEM), seeks to provide quality services without neglecting the reliability of the system. Therefore, a quality service must be closely linked to the wireless communication technologies, to technify the EEM, not only reading, but also cuts, reconnections, and other additional services that the intelligent measurement infrastructure provides through wireless technologies Such as cell or WiFi, increasingly common because of the reliability they provide in real-time data transmission. Wireless infrastructures allow us to provide coverage to the fixed terminals, determined by the electric meter, and in turn manage and plan the optimal deployment of wireless sensors (SI) in finite areas, whether urban, rural or suburban. This article proposes an optimal model for planning and deploying SI for the EEM in order to guarantee reliable wireless communication links at the lowest implementation cost. Therefore, the proposed algorithm gives global solutions within a finite scenario, making this a scalable model in time able to manage the use of available links. The SIs for the EEM are inserted into the Neighborhood Area Networks (NANs) covered by the mobile communications network.La medición de energía eléctrica (MEE), busca proporcionar servicios de calidad sin descuidar la confiabilidad del sistema. Por lo tanto, un servicio de calidad debe ir estrechamente ligada a las tecnologías de comunicación inalámbrica, para tecnificar la MEE, no solo lectura, sino también cortes, reconexiones, y otros servicios adicionales que la infraestructura de medición inteligente provee a través de tecnologías inalámbricas como celular o WiFi, cada vez más comunes debido a la confiabilidad que estas brindan en la transmisión de datos en tiempo real [1]. Las infraestructuras inalámbricas nos permiten brindar cobertura a los terminales fijos, determinados por el medidor eléctrico, y a su vez gestionar y planificar el óptimo despliegue de sensores inalámbricos (SI) en áreas finitas, ya sean, urbanas, rurales o suburbanas. Este artículo propone un modelo óptimo de planeación y despliegue de SI para la MEE con la finalidad de garantizar enlaces de comunicación inalámbricos confiables al menor costo de implementación. Por lo tanto, el algoritmo propuesto da soluciones globales dentro de un escenario finito, haciendo de este un modelo escalable en el tiempo capaz de gestionar el uso de enlaces disponibles. Los SI para la MEE, son insertados en las Redes de Área Vecindaria (NAN) cubiertas por la red de comunicaciones móviles
Localized and Configurable Topology Control in Lossy Wireless Sensor Networks
Recent empirical studies revealed that multi-hop wireless networks like wireless sensor networks and 802.11 mesh networks are inherently lossy. This finding introduces important new challenges for topology control. Existing topology control schemes often aim at maintaining network connectivity that cannot guarantee satisfactory path quality and communication performance when underlying links are lossy. In this paper, we present a localized algorithm, called Configurable Topology Control (CTC), that can configure a network topology to different provable quality levels (quantified by worst-case dilation bounds in terms of expected total number of transmisssions) required by applications. Each node running CTC computes its transmission power solely based on the link quality information collected within its local neighborhood and does not assume that the neighbor locations or communication ranges are known. Our simulations based on a realistic radio model of Mica2 motes show that CTC yields configurable communication performance and outperforms existing topology control algorithms that do not account for lossy links
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Graph-theoretic channel modeling and topology control protocols for wireless sensor networks
This report addresses two different research problems: (i) It presents a wireless channel model that reduces the complexity associated with high order Markov chains; and (ii) presents energy efficient topology control protocols which provide reliability while maintaining the topology in an energy efficient manner. For the above problems, real wireless sensor network traces were collected and extensive simulations were performed for evaluating the proposed protocols.
Accurate simulation and analysis of wireless networks are inherently dependent on accurate models which are able to provide real-time channel characterization. High-order Markov chains are typically used to model errors and losses over wireless channels. However, complexity (i.e., the number of states) of a high-order Markov model increases exponentially with the memory-length of the underlying channel.
In this report, a novel graph-theoretic methodology that uses Hamiltonian circuits to reduce the complexity of a high-order Markov model to a desired state budget is presented. The implication of unused states in complexity reduction of higher order Markov model is also explained. The trace-driven performance evaluations for real wireless local area network (WLAN) and wireless sensor network (WSN) channels demonstrate that the proposed Hamiltonian Model, while providing orders of magnitude reduction in complexity, renders an accuracy that is comparable to the Markov model and better than the existing reduced state models.
Furthermore, a methodology to preserve energy is presented to increase the network lifetime by reducing the node degree forming an active backbone while considering network connectivity. However, in energy stringent wireless sensor networks, it is of utmost importance to construct the reduced topology with the minimal control overhead. Moreover, most wireless links in practice are lossy links with connectivity probability which desires that a routing protocol provides routing flexibility and reliability at a minimum energy consumption cost. For this purpose, distributed and semi-distributed novel graph-theoretic topology construction protocols are presented that exploit cliques and polygons in a WSN to achieve energy efficiency and reliability. The proposed protocols also facilitate load rotation under topology maintenance, thereby extending the network lifetime. In addition to the above, the report also evaluates why the backbone construction using connected dominating set (CDS) in certain cases remains unable to provide connected sensing coverage in the area covered. For this purpose, a novel protocol that reduces the topology while considering sensing area coverage is presented
Distributed algorithms for extending the functional lifetime of wireless sensor networks
The functional lifetime of a wireless sensor network (WSN) is among its most important features and serves as an essential metric in the evaluation of its energy-conserving policies. Approaches for extending the lifetime of a wireless sensor node include using an on/off strategy on the sensor nodes and using a topology control algorithm on each node to regulate its transmission power. However, the need to keep the network functional imposes certain additional constraints on strategies for energy conservation. A sensing constraint imposes that the sensing tasks essential to the functionality of the WSN are not compromised. A communication constraint similarly imposes that communications essential to an application on the network remain possible even as battery resources deplete on the nodes. This dissertation presents new distributed algorithms for energy conservation under these two classes of constraints: sensing constraints and communication constraints.
One sensing constraint, called the representation constraint in this dissertation, is the requirement that active (on) sensor nodes are evenly distributed in the region of interest covered by the sensor network. This dissertation develops two essential metrics which together allow a rigorous quantitative assessment of the quality of representation achieved by a WSN and presents analytical results which bound these metrics in the common scenario of a planar region of arbitrary shape covered by a sensor network deployment. The dissertation further proposes a new distributed algorithm for energy conservation under the representation constraint. Simulation results show that the proposed algorithm is able to significantly improve the quality of representation compared to other related distributed algorithms. It also shows that improved spatial uniformity has the welcome side-effect of a significant increase in the functional lifetime of a WSN.
One communication constraint, called the connectivity constraint, imposes that the network remains connected during its functional life. The connectivity required may be weak (allowing unidirectional communication between nodes) or strong (requiring bidirectional link layer communication between each pair of communicating nodes). This dissertation develops new distributed topology control algorithms for energy conservation under both the strong and the weak connectivity constraint. The proposed algorithm for the more ideal scenario of the weak connectivity constraint uses a game-theoretic approach. The dissertation proves the existence of a Nash equilibrium for the game and computes the associated price of anarchy. Simulation results show that the algorithms extend the network lifetime beyond those achieved by previously known algorithms.Ph.D., Computer engineering -- Drexel University, 201