The IEEE 802.15.4 MAC UnreliabilityProblem: Issues and Solutions - A Survey

Wireless sensor networks are becoming increasingly common due to the proliferation of very small, integrated lowpowered sensors and mobile devices capable of gathering critical, real-time information for remote surveillance, continual monitoring, distributed target tracking etc. Studies have shown that, the deployment of such sensor networks has increased in recent years and will improve dramatically in the near future due to the advent of two standards by IEEE and ZigBee Alliance, named as IEEE 802.15.4 standard and ZigBee standard respectively. ZigBee is the only standard uniquely designed for low-power, a low-cost, low-data rate based wireless technology network, that provides network security, and application support services operating on top of the IEEE 802.15.4 Medium Access Control (MAC) and Physical (PHY) Layer wireless standard. The survey report of performance analysis of IEEE 802.15.4/ZigBee sensor networks shows that the unreliability is the major limitation of such networks, which is also termed as MAC unreliability problem. The studies highlighted that, this unreliability problem is due to the default MAC parameter settings suggested by the standard itself. Different solutions have come up to improve the reliability problem, such as setting a pre-defined value for parameters which is suitable only for static conditions, an adaptive technique for dynamic conditions based on mathematical model etc. This paper surveys a comprehensive review of causes and its available solutions to the MAC unreliability problem for IEEE 802.15.4/ZigBee sensor networks