 Tazzle iT (tazzleit.com). Broadband Telecommunications Technologies and Management ZigBee Networking ZigBee systems use the same CSMA-CA networking mechanism as that of Wireless LANs. The networking topology may be mesh, star or cluster tree as illustrated in Figure 12.12. In a star topology all ZigBee devices connect to a central device, called a coordinator, which may be connected to a network using a wireless or fixed link. Mesh topology allows all devices to communicate with each other and to a coordinator which again passes/receives data to/from a destination network. A cluster tree topology allows some nodes to act as a coordinator to sensors which have low activity factors or are remote. ZigBee has been successful in finding a niche in smart meters: electricity, water or gas utilities. These meters are connected to a coordinator which passes the usage data to a utility company using telephone lines or a mobile telecommunications standard such as GSM or W-CDMA. ZigBee Alliance is also active to promote usage of its technology in the sensor-based world of the Internet of Things (IoT). ZigBee technology competes with North America Europe Latin America Figure 12.11 ZigBee-enabled installed devices in several regions in the world 2012-2020, based on analysis by Navigant Research. Source: Ref. [14] Cluster tree Coordinator Full function device Reduced function device Figure 12.12 ZigBee networking topologies. Source: Ref. [15] Personal Wireless Communications Systems Table 12.6 A comparison of the different personal wireless communications standards Bluetooth Bluetooth 4.0 ZigBee Wi-Fi IEEE standard 802.15.1 802.15.1 802.15.4 802.11 (b, g, n) Frequency (GHz) 0.868, 0.915, 2.4 2.5 and 5 Maximum bit rate (Mbps) 0.250 11,54,600 Typical throughput 0.7-2.1 7, 25, 150 Maximum range outdoors (m) 10-100 10-100 100-250 Relative power consumption Medium Very low Very low Battery life Months to years Months to years Hours Network size Undefined 64 4000+ Bluetooth 4.0 in serving low power, low transmission rate, medium ran