In recent years, wireless sensor networks have achieved an attention on a world level. These consist of small sensors with limited power and limited resources. Wireless sensor standards developed with the special requirement for consuming low power. Some of these standards are WirelessHART, IETF 6LoWPAN, ISA100.11, IEEE 802.15.3, Wibree, IEEE 802.15.4 and ZigBee. IEEE 802.15.4 has been developed to focus on low cost of deployment, low complexity and low power consumption. IEEE devices are designed to support the physical and data link layer protocols and ZigBee defines the higher layer communication protocols built on IEEE 802.15.4 standards.