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EP-4742126-A2 - MODIFIED RFID TAG INVENTORYING PROCESS

EP4742126A2EP 4742126 A2EP4742126 A2EP 4742126A2EP-4742126-A2

Abstract

A method for a radio frequency identification (RFID) integrated circuit (IC) storing an item identifier (II) in a memory and coupled to an antenna to respond in an inventory round, the method comprising: receiving an inventorying command initiating the inventory round for the IC, wherein the inventorying command includes a collision resolution (CR) value and a response-type value; and responding in the inventory round by sending: a CR code generated based on the CR value and including one or more of: a first portion of the stored II, and a stored cyclic-redundancy-check code based on the stored II; and based on the response-type value, one or more of a tag identifier (TID) portion, a second portion of the II different from the first II portion, and no additional reply.

Inventors

  • BREWSTER, MEGAN MARIE
  • COOPER, SCOTT, A.
  • DIORIO, CHRISTOPHER, J.
  • HYDE, JOHN, D.
  • MARTINEZ, RENE DOMINIC
  • ROBSHAW, MATTHEW

Assignees

  • IMPINJ, Inc.

Dates

Publication Date
20260513
Application Date
20220120

Claims (15)

  1. A method for a radio frequency identification (RFID) integrated circuit (IC) storing an item identifier (II) in a memory and coupled to an antenna to respond in an inventory round, the method comprising: receiving an inventorying command initiating the inventory round for the IC, wherein the inventorying command includes a collision resolution (CR) value and a response-type value; and responding in the inventory round by sending: a CR code generated based on the CR value and including one or more of: a first portion of the stored II, and a stored cyclic-redundancy-check code based on the stored II; and based on the response-type value, one or more of a tag identifier (TID) portion, a second portion of the II different from the first II portion, and no additional reply.
  2. The method of claim 1, wherein the first portion of the stored II is a trailing portion of the stored II.
  3. The method of claim 1, further comprising subsequently, in the inventory round, responding with the entire II regardless of the response-type value.
  4. The method of claim 1, further comprising sending the CR code and any response based on the response-type value in response to different commands in the inventory round.
  5. The method of claim 1, further comprising subsequently, in the inventory round, responding to an acknowledgement command with a cryptographic value computed based on a tag key.
  6. The method of claim 1, wherein the second portion of the II is the entire II excluding the first II portion.
  7. The method of claim 1, wherein the TID portion is the entire TID.
  8. The method of claim 1, further comprising determining that the inventorying command initiates the inventory round for the IC by: determining that the inventorying command specifies a mask value that corresponds to a chosen data in the memory.
  9. The method of claim 8, further comprising determining the chosen data by determining a chosen data start location and a chosen data length.
  10. The method of claim 9, wherein the chosen data length is specified in the inventorying command.
  11. The method of claim 9, wherein the chosen data start location is: preset in the IC prior to receiving the inventorying command and non-reconfigurable, or reconfigurable.
  12. The method of claim 9, wherein the chosen data start location is not specified by the inventorying command.
  13. The method of claim 9, wherein determining the chosen data start location comprises: if a memory configuration identifier in the memory has a first value, then selecting a first location in the memory as the chosen data start location; and if the memory configuration identifier has a second value, then selecting a second location in the memory as the chosen data start location.
  14. The method of claim 13, wherein the first and second locations in the memory are in a same memory bank of the memory.
  15. A radio frequency identification (RFID) integrated circuit (IC) configured to be coupled to an antenna, the IC comprising: a memory configured to store data; a transceiver configured to receive commands and send replies; and a processing block coupled to the memory and the transceiver, wherein the processing block is configured to perform the actions of one or more of claims 1 through 14.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/140,222 filed on January 21, 2021, and U.S. Provisional Patent Application Serial No. 63/143,166 filed on January 29, 2021. The disclosures of the above applications are hereby incorporated by reference for all purposes. BACKGROUND Radio-Frequency Identification (RFID) systems typically include RFID readers, also known as RFID reader/writers or RFID interrogators, and RFID tags. RFID systems can be used in many ways for locating and identifying objects to which the tags are attached. RFID systems are useful in product-related and service-related industries for tracking objects being processed, inventoried, or handled. In such cases, an RFID tag is usually attached to an individual item, or to its package. The RFID tag typically includes, or is, a radio-frequency (RF) integrated circuit (IC). In principle, RFID techniques entail using an RFID reader to inventory one or more RFID tags, where inventorying involves singulating a tag, receiving an identifier from a tag, and/or acknowledging a received identifier (e.g., by transmitting an acknowledge command). "Singulated" is defined as a reader singling-out one tag, potentially from among multiple tags, for a reader-tag dialog. "Identifier" is defined as a number identifying the tag or the item to which the tag is attached, such as a tag identifier (TID), electronic product code (EPC), etc. An "inventory round" is defined as a reader staging RFID tags for successive inventorying. The reader transmitting an RF wave performs the inventory. The RF wave is typically electromagnetic, at least in the far field. The RF wave can also be predominantly electric or magnetic in the near or transitional near field. The RF wave may encode one or more commands that instruct the tags to perform one or more actions. The operation of an RFID reader sending commands to an RFID tag is sometimes known as the reader "interrogating" the tag. In typical RFID systems, an RFID reader transmits a modulated RF inventory signal (a command), receives a tag reply, and transmits an RF acknowledgment signal responsive to the tag reply. A tag that replies to the interrogating RF wave does so by transmitting back another RF wave. The tag either generates the transmitted back RF wave originally, or by reflecting back a portion of the interrogating RF wave in a process known as backscatter. Backscatter may take place in a number of ways. The reflected-back RF wave may encode data stored in the tag, such as a number. The response is demodulated and decoded by the reader, which thereby identifies, counts, or otherwise interacts with the associated item. The decoded data can denote a serial number, a price, a date, a time, a destination, an encrypted message, an electronic signature, other attribute(s), any combination of attributes, and so on. Accordingly, when a reader receives tag data it can learn about the item that hosts the tag and/or about the tag itself. An RFID tag typically includes an antenna section, a radio section, a power-management section, and frequently a logical section, a memory, or both. In some RFID tags the power-management section includes an energy storage device such as a battery. RFID tags with an energy storage device are known as battery-assisted, semiactive, or active tags. Other RFID tags can be powered solely by the RF signal they receive. Such RFID tags do not include an energy storage device and are called passive tags. Of course, even passive tags typically include temporary energy- and data/flag-storage elements such as capacitors or inductors. BRIEF SUMMARY This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. Examples are directed to modifying RFID tag inventorying. In some examples, an inventorying command initiating an inventory round may include a collision resolution (CR) value and a response-type value. A tag receiving the inventorying command may generate a CR reply based on the CR value by identifying, based on the CR value, a CR code. The CR code may include a trailing item identifier (II) portion, a stored cyclic-redundancy-check code, or a pseudorandom number. The tag may then send the CR reply including the CR code to the reader. Upon receiving a first acknowledgment command in response to the CR reply, the tag may refrain from replying to the first acknowledgment command if the response-type value indicates that no acknowledgment reply is to be sent. Alternatively, the tag may reply by sending an acknowledgment code indicated by the response-type value. The acknowledgment code may include a tag identifier (TID) portion, another II portion, and the