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

2. 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
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.

3. What is ZigBee? ZigBee ZigBee Alliance
Technology that addresses the market needs for cost-effective wireless networking solutions based on IEEE standard
IEEE :
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 ( 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 standard.
Six promoters (Honeywell, Invensys, Mitsubishi, Motorola, Philips, and Samsung) and more than 80 participants
We can think of IEEE 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 standard and adds the logical network and application software

4. 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.

5. 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