Session flag control for RFID tags
AssigneeNXP B.V.
InventorRoland Brandl
Life of this patent
Estimating the term…
Abstract
Various exemplary embodiments relate to an integrated circuit (IC) including: an inventoried flag configured to indicate whether the integrated circuit has been inventoried in a current inventory round; and an event detector configured to detect a tag event at the integrated circuit and reset the inventoried flag based on the tag event. In various embodiments, the IC further includes a timer circuit configured to measure a predetermined time since the inventoried flag was set and to prevent the reset of the inventoried flag until the predetermined time has expired.
Claims20
An integrated circuit (IC) comprising:
- an inventoried flag configured to indicate whether the integrated circuit has been inventoried in a current inventory round;
- and
- an event detector configured to detect a tag event at the integrated circuit, the tag event comprising an external event at the location of the tag that is detected by the tag, and reset the inventoried flag based on the tag event.
A method performed by a radio frequency identification (RFID) tag, the method comprising:
- setting an inventoried flag to indicate that the RFID tag has been inventoried in a current inventory round;
- detecting a tag event at the RFID tag, the tag event comprising an external event at the location of the tag that is detected by the tag;
- and
- resetting the inventoried flag in response to detecting the tag event to indicate that the RFID tag has not been inventoried in the current inventory round.
A method performed by a radio frequency identification (RFID) reader, the method comprising:
- conducting a first inventory round of RFID tags within a field of the RFID reader that have an inventoried flag set to a first value;
- changing the inventoried flag of tags that respond to a second value;
- storing an identifier of each RFID tag that responds to the first inventory round;
- conducting a second inventory round of RFID tags within the field of the RFID reader that have an inventoried flag set to the first value;
- determining whether an identifier of a tag that responds to the second inventory round was stored for the first inventory round;
- and
- if the identifier of a tag that responds to the second inventory round was stored, determining that a tag event has occurred at the RFID tag.
Dependencies are inferred from the claim text.