1. How is a sensor network defined?

A sensor network is made up of two types of nodes: simple sensors and information collectors called sinks.

The sensor consists of a microcontroller and a radio circuit. The microcontroller is simple and easy to embed. Several manufacturers, such as Texas Instruments, Atmel, Freescale... produce them. This device must meet the requirement of low power consumption, while being able to execute simple operations and have a memory for storing information. The device must also be able to have an idle state, during which it consumes an infinitesimal amount of energy. These idle states can sometimes last a very long time. The sensor can wake up only to capture the physical quantity to be measured, and also to perform network operations such as communicating with neighboring sensors or relaying information from other sensors.

The radio circuit enables...