Localization in Wireless Sensor Networks

A Wireless Sensor Network (WSN) is a network of many small sensing and communicating devices called sensor nodes. Each node has a CPU, battery supply, limited number of sensors and a radio transceiver for communication. Interconnection between nodes is achieved via the transceiver. Typically, a WSN contains a node that connects the network to a more capable computer, and probably to a network of general purpose computers through it. Sensors attached to these nodes allow them to sense various phenomena within the environment. The typical purpose of a sensor network is to collect data via sensing interfaces and propagate those data to the central computer, allowing easy monitoring of an environment. Although a node is capable of dealing with a variety of jobs, it has many shortcomings as well. The majority of the nodes currently available in the market are battery-operated, and hence they have a limited life-time. Moreover, the memory capacity of a node is also limited. Lifetime, processing and storage restrictions directly affect the algorithms designed for sensor networks. As an example, a routing algorithm for WSNs must be energy and memory efficient. Since radio transmissions consume a significant amount of energy, researchers generally seek ways to reduce radio communication as much as possible. However, when more information is stored and more computation is done as to reduce the communication costs, energy consumption of the processor and memory components are becoming an important issue. Design choices have to be made, and these also depend on the intended application.