Overview

Sensor networks are used to closely monitor physical phenomena. Such networks are made up of nodes which have the ability to monitor one or more aspects of the physical world (e.g. light, heat, vibration). These nodes are also capable of communicating with one another and usually a central device which makes use of the gathered information. A number of applications for sensor networks are:

• Habitat monitoring to help protection of rare species[3,4]
• Battlefield surveillance for detection of enemy intrusions[5]
• Traffic surveillance and control[6]
• Early detection of forest fires, volcano eruptions, flooding and earthquakes.
• Observing dispersion of hazardous chemicals in event of an emergency(e.g. Oil tanker leakage, biochemical attack detection)
• Monitoring conditions of industrial instruments and sub-components (e.g. Monitoring rail track vibration levels with real time feedback)

Due to the nature of applications for sensor networks, nodes are usually required to be very small in size, have some processing capabilities and be cheap since a large number of them are to be incorporated in a network. Also as these networks are typically required to be highly versatile, the ability of nodes to communicate wirelessly adds substantially to the practicality element of such systems. All these features and requirements enforces certain limitations on these networks.