Glossary: Multi-tag reading

Multi-tag reading (anti-collision)

With the basic electronics for interrogation, only one tag may be in the interrogation zone at a time, or responses will overlap, confusing the reader. Schemes which allow for multiple tags in the interrogation zone have been demonstrated. They can all be read in a very short time without confusion - sometimes up to 1000 at a time. This is "anti-collision software". Standardised methodologies are emerging for all chip tags, - an advantage over chipless tags, where anti-collision capability is primitive or non-existent. Anti-collision capability can reside in hardware rather than software in certain cases.

For applications demanding many tags, tags will need to be read quickly, and if billions of tags are being used every year it must be assumed that there will be more than one tag within the interrogatory zone of a reader at some time in most of these applications. It must distinguish and read tags from multiple suppliers, and be clever enough to 'ignore' tags within the interrogatory zone that should not be there. This technology is readily available today.