A WSN [1–8] can be defined as a network of devices, denoted as nodes, which can sense the environment and communicate the information gathered from the monitored field (e.g., an area or volume) through wireless links [9]. The data is forwarded, possibly via multiple hopsxx, to a xsink (sometimes denoted as controller or monitor) that can use it locally or is connected to other networks (e.g., the Internet) through a gateway. The nodes can be stationary or moving. They can be aware of their locations or not. They can be homogeneous or not. Monitoring and communication are performed cooperatively by the nodes