Book Title: ZigBee Network Protocols and Applications

In this chapter, the IEEE 802.15.4 MAC layer is modeled using a per-node Markov chain model. Using this model, expressions for various performance metrics including delay , throughput, power consumption, and efficiency, are derived and such expressions are subsequently validated against the corresponding values obtained via simulation. The simplifying assumptions required by the Markov-chain analysis are studied and their impact on the performance metrics is quantified. As already alluded to in previous chapters of this book, ZigBee is arguably the most prominent alliance dedicated to low-power embedded systems. It is a facilitator of applications pertaining to home and building automation, smart metering, health care, among many others. Its link and access protocols rely on the specifications of IEEE 802.15.4 [1], whereas higher layers are subject to the profile definition of the ZigBee special interest group (SIG). The internet engineering task force (IETF), however, has lately commenced standardizing networking protocols within their 6LoWPAN [2] and ROLL [3] which are assuming IEEE 802.15.4 link layer technology; ZigBee may thus adopt IETFs networking solution in the future. In short, ZigBee is gaining in importance and the underlying IEEE standard ensures that technology is available from multiple vendors. On the downside, true deployment success stories are fairly rare still which might be due to the fact that it operates in the highly interfered 2.4 GHz ISM band. Also, Zigbee is not alone and needs to compete with Wibree, a low-power solution based on Bluetooth; Wavenis, the only ultra low-power solution on the smart metering market today; Zwave, a short range solution backed by Intel and Cisco; IO-Homecontrol, an international alliance of worldwide leaders for building management solutions; Konnex/KNX, a European standard for home & building automation; Wireless HART, a SIG offering a interoperable wireless communication standards for process measurement and control applications; just to mention a few.