Wireless sensor networks looking to Zigbee Alliance By Bryon Gloden, Murat Senel, and Waseem Sheikh

What is a sensor? Small, autonomous computers, containing: sensors that allow data acquisition “computer’’ that allows data processing radio that allows data communication Battery operated Ability to self-organize into ad hoc networks Programmable, running TinyOS http://www.tinyos.net Example: PicoRadio, 2 AA bateries, 40 Kbps RFM TR 100, Detachable sensor boards: temperature, photo, microphone, Applications include civil and military Imagine a golf course that can sense rainfall, and adjust the automatic sprinkler system to delay a scheduled watering session or focus on parts of the course that didn't get as much rain as others. Or a hotel that can detect when a room is vacant, and turn off the heating or cooling systems in that room to save energy.

What is ZigBee? ZigBee ZigBee Alliance Technology that addresses the market needs for cost-effective wireless networking solutions based on IEEE 802.15.4 standard IEEE 802.15.4: Wireless MAC and PHY specifications for low-rate wireless personal area networks (LR-WPANs) Ultra-low complexity, ultra-low cost, ultra-low power consumption, and low data rate (20-250 kb/s) wireless connectivity among inexpensive devices Lower power, lower cost than other WPANs (e.g. Bluetooth) ZigBee Alliance Non-profit industry consortium defining a global specification for reliable, cost-effective, low power wireless applications based on the IEEE 802.15.4 standard. Six promoters (Honeywell, Invensys, Mitsubishi, Motorola, Philips, and Samsung) and more than 80 participants We can think of IEEE 802.15.4 as the physical radio and ZigBee as the logical network and application software. ZigBee takes full advantage of the physical radio specified by the IEEE 802.15.4 standard and adds the logical network and application software

Article Summary Planned certification program to assure sensors meet specifications, interoperability and manageability. RTM fourth quarter of 2004. Low cost of sensors will likely make them a more favorable option over other WPAN technologies.

Article Strengths and weaknesses Strong Points Interoperation compatibility Gives practical applications of sensor networks Advantages of Zigbee over Wi-Fi and Bluetooth Real-time data analysis Advantages of Zigbee tags over passive RFID Scalability issues Weak Points Lack of specifications, such as, modulation scheme, power level, medium access Security issues Cost of Zigbee chipset Passive/active RFIDs