ACM TechNews

A Network That Builds Itself

Technology Review (09/03/08) Fitzgerald, Michael

The National Institute of Standards and Technology (NIST) has developed two experimental ad hoc wireless networks that instruct emergency workers how to deploy transmitters to ensure a good signal. The NIST prototypes, which have been under development for more than three years, use algorithms to monitor the signal-to-noise ratio of transmissions and automatically warn when a new node should be deployed. NIST's Nader Moayeri says the prototypes aim to avoid fixed rules because situations change depending on the area. The methods also need to be adaptable because deploying too many nodes can lead to excessive costs and communication delays. Initially, NIST considered sending short messages between nodes to see how data packets were lost in transit, except that the people deploying the network would not detect a weak connection immediately. Using an algorithm to measure the signal-to-noise ratio avoids this problem and provides a clearer picture of connection strength. NIST built two prototypes using off-the-shelf hardware, one that operates at 900 megaherz and uses motes to transmit radio signals, and one based on a Wi-Fi network operating at 2.4 gigahertz. The mote-based system has LED lights that automatically change from green to red when a new node needs to be deployed, and the Wi-Fi system issues alerts through a handheld or tablet computer connected to the network.

http://www.technologyreview.com/Infotech/21327/?a=f

---

© Copyright 2008 Information, Inc. This service may be reproduced for internal distribution.