RFID Glossary

RFID Glossary : RFID Tag Collision

2020-04-08 18:08:50 M&W SmartCard 33

Tag collision in RFID systems happens when multiple tags are energized by the RFID tag reader simultaneously, and reflect their respective signals back to the reader at the same time. This problem is often seen whenever a large volume of tags must be read together in the same RF field.The reader is unable to differentiate these signals; tag collision confuses the reader.

Different systems have been invented to isolate individual tags; the system used may vary by vendor. For example, when the reader recognizes that tag collision has taken place, it sends a special signal (a "gap pulse"). Upon receiving this signal, each tag consults a random number counter to determine the interval to wait before sending its data. Since each tag gets a unique number interval, the tags send their data at different times. 

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Index of related articles:

Active Tag (Active RFID Tag)
Amplitude Modulation (AM)
Antenna (RFID Tag Antenna)
Back scatter (RFID back scatter)
Contactless smart card
Chipless RFID tag
Contactless Credit Cards
Closed Systems (or Closed Loop Systems)
Code plate (RFID code plate)
Continuous Wave (CM)
Electromagnetic Interference (EMI)
Electronic Article Surveillance (EAS)
Electronic Product Code (EPC)
Error Correcting Code (ECC)
Error Correcting Mode
Error Correcting Protocol
Factory Programming
Field Programming
Frequency Modulation (FM)
Frequency Shift Keyed Modulation (FSKM)
Frequency Hopping
Inductive Coupling
Passive RFID Tag (or Passive Tag)
Phase Modulation (PM)
Pulse Duration
RF Fibers
RFID Reader
RFID Tag Collision
RFID tag
Smart label (RFID Smart Label)
RFID Reader Collision
Smart cards
Transponder for RFID

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