Circuit Sage Tools
RFSim99 is a free linear S-parameter based circuit simulator offering schematic capture, simulation, 1 port and 2 port S-parameter display and file support, tolerance analysis, stability circles, and much more.
Nathan Iyer's Cascade:
Windows program calculates NF, Gain, IIP3 of cascaded components in a receiver.
TI Zigbee presentation:
Very good overview of Zigbee applications and protocols
Palo Wireless' Zigbee page:
Great resource for learning includes tutorials, news, articles
Quick comparison between Zigbee and other short range standards:
Zigbee compared to Bluettoth and other protocols
Detailed data sheet of Zigbee transceiver:
134-page application note of TI's Zigbee transceiver
TI's Zigbee/low-power RF site:
Tools and application notes for Zigbee
Great wireless sensor networks article by The Economist:
Fun read, very informative
WSN's presentation at Paderborn University in Germany:
Provides supplementary material for the book Protocols and Architectures for Wireless Sensor Networks.
Zigbee Wireless Networking by D. Gislason:
from description: "...this book is written for engineers who plan to develop ZigBee applications and networks, to understand how they work, and to evaluate this technology to see if it is appropriate to a particular project..."
ZigBee Wireless Networks and Transceivers by S. Farahani:
from description:...This book will explain the ZigBee protocol, discuss the design of ZigBee hardware, and describe how to design and implement ZigBee networks. The book has a dedicated website for the latest technical updates, ZigBee networking calculators, and additional materials. Dr. Farahani is a ZigBee system engineer for Freescale semiconductors Inc...."
Protocols and Architectures for Wireless Sensor Networks by H. Karl and A. Willig:
From description:"... * Covers architecture and communications protocols in detail with practical implementation examples and case studies. * Provides an understanding of mutual relationships and dependencies between different protocols and architectural decisions. * Offers an in-depth investigation of relevant protocol mechanisms. * Shows which protocols are suitable for which tasks within a wireless sensor network and in which circumstances they perform efficiently. * Features an extensive website with the bibliography, PowerPoint slides, additional exercises and worked solutions. ..."