Radio frequency identification (RFID) tag response modulation

• US 7,911,323 B2
• Filed: 09/29/2006
• Issued: 03/22/2011
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Posamentier, Joshua
• Primary Examiner(s): Wu; Daniel
• Assistant Examiner(s): POINT, RUFUS C
• Application Number:
  US11/540,012
• Publication Number:
  US 20080079579A1
• Time in Patent Office: 1,635 Days
• Field of Search: 340/57.1, 340/572.2, 340/568.1, 340/116, 340/331, 340/367, 340/10.1, 340/10.2, 340/10.3, 340/572.1, 340/572.4, 340/10.4
• US Class Current: 340/10.1
• 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 7/10029 the collision being resolved in the time domain, e.g. using binary tree search or RFID responses allocated to a random time slot
• 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: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders

Abstract

Embodiments of radio frequency identification (RFID) tag response modulation are described.

Claims

1. An apparatus for interrogating radio frequency identification (RFID) tags, a reader comprising:

a transmitter; and

a module to form a request to be transmitted by the transmitter, the request to indicate a number of timeslots and a number of modulation modes supported by the module to process within the apparatus one or more responses to the request from a number of RFID tags, wherein the number of timeslots and the number of modulation modes are optimized by the apparatus, based upon an Q value that addresses the number of RFID tags within the apparatus, and the value 2^Q represents the available timeslots to receive responses from the RFID tags;

wherein each RFID tag comprises a control logic to;

randomly select one of a plurality of modulation modes, wherein the randomly selected modulation modes is selected from an optimized range of modulations modes indicated in the request, received, wherein each said modulation mode corresponds to a particular data transfer rate and wherein the optimized range of modulation modes is determined based upon the known number of radio frequency identification (RFID) tags; and

form a response to the request to be transmitted.

2. An apparatus as described in claim 1, wherein each said modulation mode corresponds to a particular data transfer rate.

3. An apparatus as described in claim 1, wherein the request is to configure the one or more radio frequency identification (RFID) tags to select a respective said timeslot and a respective said modulation mode and to transmit a respective said response using the selected said times lot and the selected said modulation mode.

4. An apparatus as described in claim 1, wherein at least one said radio frequency identification (RFID) tag is a passive tag such that a respective said response is formed, at least in part, using power harvested from the transmitter.

5. An apparatus as described in claim 1, wherein the module includes a plurality of modulation filters to demodulate the response.

6. An apparatus as described in claim 5, wherein the plurality of modulation filters are executable in parallel.

7. An apparatus as described in claim 5, wherein the module includes a digital signal processor to execute the modulation filters in parallel.

8. A radio frequency identification (RFID) tag comprising:

a receiver;

a power harvester to harvest power from a request received by the receiver;

a transmitter;

and control logic to;

randomly select one of a plurality of timeslots, wherein the randomly selected timeslots is selected from an optimized range of timeslots indicated in the request received, wherein the optimized range of timeslots is determined within the RFID tag based upon a number of RFID tags in an interrogation zone, based upon a Q value that addresses the number of RFID tags within the apparatus, and the value 2^Q represents the available timeslots to receive responses from the RFID tags;

randomly select one of a plurality of modulation modes, wherein the randomly selected modulation modes is selected from an optimized range of modulations modes indicated in the request received, wherein each said modulation mode corresponds to a particular data transfer rate and wherein the optimized range of modulation modes is determined based upon the known number of RFID tags; and

form a response to the request to be transmitted by the transmitter in the selected said timeslot using the selected said modulation mode, the response being formed at least in part from power harvested by the power harvester.

9. An RFID tag as described in claim 8, wherein the RFID tag is associated with a product;

and the control logic is to return an identification of the product in the response.

10. An interrogator device comprising:

a transmitter within an interrogator device to transmit a request to a number of radio frequency identification (RFID) tags, wherein the request indicates a number of the timeslots and a number of the modulation modes supported by the module, wherein the number of timeslots and the number of modulation modes are optimized by the interrogator device, based upon the known number of radio frequency identification RFID tags within the interrogator device, based upon a Q value that addresses the number of RFID tags within the interrogator device, and the value 2^Q represents the available timeslots to receive responses from the RFID tags;

a receiver within the interrogator device to receive a plurality of responses to the request from the known number of radio frequency identification (RFID) tags;

a module within the interrogator device to execute a plurality of modulation filters in parallel to process the plurality of responses received in a plurality of timeslots;

wherein each RFID tag comprises a control logic to;

randomly select one of a plurality of modulation modes, wherein the randomly selected modulation modes is selected from an optimized range of modulations modes indicated in the request, received, wherein each said modulation mode corresponds to a particular data transfer rate and wherein the optimized range of modulation modes is determined based upon the known number of radio frequency identification (RFID) tags; and

form a response to the request to be transmitted;

and a display device of the interrogator device to display a result of the processing.

11. A system as described in claim 10, wherein each said response is received in a respective said timeslot using a respective said modulation mode that is selected by a respective said radio frequency identification (RFID) tag.