RFID-based item presence detection
AssigneeImpinj, Inc.
InventorsBalaji Shyamkumar, Kurt Sundstrom, Scott Cooper, Jayasuryan Iyer, Sandesh Doddameti
Life of this patent
Estimating the term…
Abstract
An RFID-based item tracking system may use statistical methods to determine whether a tag or tagged item that does not respond when inventoried is present in a particular zone or reader antenna field-of-view. In one embodiment, the item tracking system may determine an observability of an item based on one or more initial trials. Upon not detecting the item in one or more subsequent trials, the item tracking system may estimate whether the item is still present based on the observability.
Claims20
A method for estimating whether an item is in a zone, the method comprising:
- in at least one initial trial:
- transmitting at least a first RF wave into the zone;
- querying, by modulating the first RF wave, the item in the zone;
- receiving an identifier from the item;
- and
- determining, based on the at least one received identifier, an observability of the item in the zone;
- and
- in at least one first subsequent trial:
- transmitting at least a second RF wave into the zone;
- querying, by modulating the second RF wave, the item in the zone;
- and
- upon not receiving the identifier, estimating whether the item is still in the zone based on the observability and an observability threshold.
A Radio Frequency Identification (RFID) system configured to estimate item presence in a zone, the system comprising:
- an RFID reader system configured to:
- in at least one initial trial:
- transmit at least a first RF wave into the zone;
- query, by modulating the first RF wave, the item in the zone;
- and
- receive an identifier from the item;
- and
- in at least one first subsequent trial:
- transmit at least a second RF wave into the zone;
- and
- query, by modulating the second RF wave, the item in the zone;
- and
- a processor block configured to:
- determine, based on the at least one initial trial, an observability of the item in the zone;
- and
- upon determining that the identifier was not received in the at least one first subsequent trial, estimate whether the item is still in the zone based on the observability and an observability threshold.
A Radio Frequency Identification (RFID) system configured to estimate the presence of an item, the system comprising:
- a synthesized-beam reader (SBR) system configured to:
- generate a first SBR beam corresponding to a first zone;
- in at least one initial trial:
- query the item by modulating the first SBR beam;
- and
- receive an identifier from the item;
- and
- in at least one subsequent trial, query the item by again modulating the first SBR beam;
- and
- a processor block configured to:
- determine, based on the at least one initial trial, an observability of the item;
- and
- upon determining that the identifier was not received in the at least one subsequent trial, estimate a presence of the item based on the observability and an observability threshold.
Dependencies are inferred from the claim text.