Mobility Models for Next Generation Wireless Networks

Chapter 14

Wireless Sensor Networks

14.1 Wireless Sensor Networks: State of the Art

Wireless sensor networks are a class of short-range wireless networks composed of a number of sensor nodes and one or more base stations (also called sinks) communicating with each other through a wireless transceiver.

A sensor node is typically composed of several parts: a wireless transceiver for communication, one or more sensors (e.g., temperature, pressure, humidity, accelerometer, etc.), a microcontroller unit, and an energy source, typically a battery. In some cases, sensor nodes are also equipped with actuators allowing the node to undertake some action (e.g., reducing illumination) in response to specific environmental conditions (e.g., a too high illumination level). If a network is composed of nodes, some of which also include actuators, it is called a wireless sensor and actuator network. The size, complexity, and cost of a sensor node vary widely depending on the specific application scenario: there can be sensor nodes as small as a coin costing a few dollars, as well as sensor nodes as large as a shoebox costing hundreds of dollars.

Sink nodes are relatively more powerful nodes, which typically are not equipped with sensors/actuators, but they have a more powerful processing unit, a possibly more powerful wireless transceiver, and other network interfaces usually allowing connection to the Internet. Furthermore, sink nodes are typically power-plugged, so energy consumption, which is ...