INTRODUCTION
The IEEE 802.15.4 has recently been adopted as a communication standard for low data rate, low power consumption and low cost Wireless Personal Area Networks. This protocol is quite flexible for a wide range of applications if appropriate tuning of its parameters is carried out. Importantly, the protocol also provides real-time guarantees by using the Guaranteed Time Slot (GTS) mechanism. Indeed, the GTS mechanism is quite attractive for time-sensitive Wireless Sensor Network (WSN) applications, particularly when supported by cluster-tree network topologies, such as defined in the ZigBee standard. It is primarily designed for the wide ranging automation applications and to replace the existing non-standard technologies. It currently operates in the 868MHz band at a data rate of 20Kbps in Europe, 914MHz band at 40Kbps in the USA, and the 2.4GHz ISM bands Worldwide at a maximum data-rate of 250Kbps.
Some of its primary features being:
• Standards–based wireless technology
• Interoperability and worldwide usability
• Low data–rates
• Ultra low power consumption
• Very small protocol stack
• Support for small to excessively large networks
• Simple design
• Security, and
• Reliability
