[LINK] Now 256 RFID tags at 20 feet simulaneously

[stephen at melbpc.org.au]

Advanced Technology Week in Review: May 16  

"Testbed streamlines RFID development" 

. RFID tags are used for everything from inventory management to toll 
collection to passport identification to tracking luggage. 

Most tags are passive, including a chip and an antenna that absorbs a 
radio signal to back-scatter its identity to a nearby reader. 

The biggest problem with RFID tags is the sheer volume -- warehouses and 
store shelves often contain hundreds of tags within range of a reader, 
many hidden behind other tags. 

When multiple tags are within range of a reader, the usual protocol is to 
interrogate the tag with the strongest signal, then put it to sleep and 
proceed on to the next strongest signal. That serial process can be time 
consuming. 

Instead, the Georgia Tech test bed uses an anti-collision system capable 
of transmitting multiple, unique signals. The system allows up to 256 tags 
to be interrogated simultaneously. 

Instead of requiring readers to be within about a foot of tags, the 
Georgia Tech testbed can communicate with RFID tags within 400 square feet 
of the tester.

<http://www.eetimes.com/galleries/slideShow.jhtml?galleryID=20&imageID=3>
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Cheers people
Stephen Loosley
Victoria, Australia