Calculation of an Optimum Mobile Sink Path in a Wireless Sensor Network

6 Feb

A wireless sensor network (WSN) is a collection of spatially distributed, resource-constrained sensor nodes, deployed within an application area, to monitor a specific event or set of events. These sensor nodes are standalone devices without access to a continuous energy source and are located either within or close to the phenomena they are observing. The nodes communicate with one or more central control point(s), generally called a sink or base station. A typical sensor node comprises a sensing unit, a small processing unit to perform simple computations, a transceiver unit to connect nodes to the network and a power unit. Some nodes are also equipped with a location finding system [1]. A WSN application contains hundreds to thousands of sensor nodes. These sensor nodes are designed for unattended operation and are generally stationary after deployment.

One of the main criteria in designing a WSN application is prolonging network lifetime and preventing connectivity degradation through aggressive energy management. There is a trade-off between a node’s energy, node range, size and cost. Due to the need to conserve battery lifetime, the sensor nodes operate with low duty cycles and communicate sporadically, over short distances with low data rates. In WSNs the flow of data is predominantly unidirectional, from nodes to sink [2]. The limited resources, non-renewable power supply and short radio propagation distances, (and hence large number required for deployment), of sensor nodes impose constraints on WSN applications not found in wired networks. A WSN differs from local area networks in the following key areas [3, 4]:

  • Each sensor node communicates with one or more base stations (sinks). Traffic is mainly between individual sensor nodes and a base station.

  • The network topology is a multi-hop star-tree that is either flat or hierarchical.

  • They are used in diverse applications which may have different requirements for QoS and reliability.

  • Most network applications require dense deployment and physical collocation of nodes.

  • Individual sensor nodes have limited resources in terms of processing capability, memory and power.

  • Power constraints result in small message sizes

  • The placement of nodes in a WSN is application dependent and may not be pre-determined.

PDF download: InTech-Calculation_of_an_optimum_mobile_sink_path_in_a_wireless_sensor_network




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