Low Power Wireless Networks are sometimes called “Wireless Sensors Networks” (WSNs). WSN technology addresses several requirements; the cost has to be low and the devices small, the power consumption has to be low and it requires an unlicensed radio band. WSN also must support a large number of nodes and be flexible in regards to simple deployment and network extension. Low data rate is sufficient and it needs data and network security support. Among existing wireless technologies, WSN is the only one that targets simple communication with low data rates and low power consumption.