Method, system, and apparatus for communications in a RFID system

• US 7,928,843 B2
• Filed: 11/14/2005
• Issued: 04/19/2011
• Est. Priority Date: 02/12/2001
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Arneson, Michael R., Bandy, William R., Powell, Kevin J., Shanks, Wayne E.
• Primary Examiner(s): Lee; Benjamin C
• Assistant Examiner(s): Pham; Lam P
• Application Number:
  US11/272,135
• Publication Number:
  US 20060061474A1
• Time in Patent Office: 1,982 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.7, 340/10.1, 340/10.31, 340/10.32, 340/10.42, 340/10.5, 235/375, 235/385
• US Class Current: 340/572.1
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 19/0713 the arrangement including a power charge pump
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: G06K 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: G06K 7/10108 interrogating only those RFIDs that fulfill a predetermined requirement, e.g. selecting all RFIDs having the same speed and moving in a cloud like fashion, e.g. on the same train; interrogating only RFIDs having a certain predetermined temperature, e.g. in the same fridge, another possibility being the active ignoring of a group of tags that fulfill a predetermined requirement, equivalent to the Boolean NOT operation
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G08B 13/2485 Simultaneous detection of multiple EAS tags
• CPC Class Codes: G11C 5/142 Contactless power supplies, e.g. RF, induction, or IR
• CPC Class Codes: H04L 7/0331 with a digital phase-locked loop [PLL] processing binary samples, e.g. add/subtract logic for correction of receiver clock H04L7/0337 takes precedence

Abstract

A method, system, and apparatus for interrogating a radio frequency identification (RFID) tag population are described. Tags are interrogated by a reader. The reader and tags engage in communication according to communications algorithms, where data symbols are exchanged between the reader and tags. Furthermore, a reader implicitly controls the operating state of every tag in the tag population by transmitting a single data symbol. Bit patterns may be collected from the tags by the reader, using a variety of interrogation techniques. In a general interrogation, the reader exchanges symbols with the tag population to interrogate the entire tag population. In a specific interrogation, a reader exchanges symbols with the tag population to target a particular tag identification number. Tags may also be placed in a superposition state by the reader, where they respond whenever a received data symbol matches the next bit of their identification number.

Claims

1. A method of reading radio frequency identification (RFID) tags associated with items classified according to a packaging hierarchy, wherein the RFID tags each have a identification number assigned thereto, comprising:

(a) determining a level in the packaging hierarchy for items desired to be read;

(b) determining a bit pattern corresponding to the determined level; and

(c) communicating with tags according to an interrogation protocol to read tags that have the determined bit pattern in a predetermined location of their identification number.

2. The method of claim 1, wherein step (c) comprises:

transitioning tags that do not have the determined bit pattern in the predetermined location of their identification number to a mute state.

3. The method of claim 1, wherein the interrogation protocol is a binary protocol.

4. The method of claim 1, wherein the level can be an item level, a box level, a carton level, a tote level, or a pallet level.

5. A radio frequency identification (RFID) tag associated with an item classified according to a packaging hierarchy, wherein the RFID tag includes an identification number assigned thereto, comprising:

a substrate;

an antenna on the substrate;

a storage that stores a bit pattern in a predetermined location of the an identification number, wherein the identification number includes a bit pattern identifies a level in a packaging hierarchy for the RFID tag;

a receiver coupled to the antenna, wherein the receiver receives a carrier signal received by the antenna from a reader, the carrier signal including an interrogation protocol for reading tags that have the bit pattern in the predetermined location of the identification number; and

a modulator coupled to the antenna, wherein the modulator is configured to backscatter modulate the carrier signal with bits of the bit pattern corresponding to a level for the RFID tag predetermined by the reader, to identify the level in the packaging hierarchy for the RFID tag to the reader.

6. The tag of claim 5, wherein the bit pattern represents an item level, a box level, a carton level, a tote level, or a pallet level in the packaging hierarchy.

9. The RFID tag of claim 5, wherein the interrogation protocol causes an RFID tag not having a bit pattern in the predetermined location of its identification number to transition to a mute state.

10. The RFID tag of claim 5, wherein the interrogation protocol is a binary protocol.

11. The RFID tag of claim 5, wherein the storage includes non-volatile storage that stores the bit pattern.

7. A method in a radio frequency identification (RFID) tag associated with an item classified according to a packaging hierarchy for communicating with a reader, comprising:

storing an identification number in the RFID tag, wherein the identification number includes a bit pattern, that identifies a level in a the packaging hierarchy for the RFID tag;

receiving a carrier signal from a reader, the carrier signal including an interrogation protocol for reading tags that have the bit pattern in a predetermined location of the identification number; and

backscatter modulating the carrier signal with bits of the bit pattern corresponding to a level for the RFID tag predetermined by the reader, to identify the level in the packaging hierarchy for the RFID tag to the reader.

8. The method of claim 7, wherein said backscatter modulating comprises:

identifying the level in the packaging hierarchy for the RFID tag as an item level, a box level, a carton level, a tote level, or a pallet level.

12. The method of claim 7, further comprising transitioning tags that do not have the bit pattern in the predetermined location of their identification number to a mute state.

13. The method of claim 7, wherein the interrogation protocol is a binary protocol.