RF identification system with restricted range

• US 20050040961A1
• Filed: 09/09/2004
• Published: 02/24/2005
• Est. Priority Date: 04/11/1995
• Status: Abandoned Application

• Current Assignee: Round Rock Research LLC
• Original Assignee: Round Rock Research LLC
• Inventors: Tuttle, John R.
• Application Number:
  US10/938,917
• Publication Number:
  US 20050040961A1
• Time in Patent Office: Days
• US Class Current: 340/693.300
• CPC Class Codes: B07C 7/005 Computer assisted manual sorting, e.g. for mail
• CPC Class Codes: B22D 19/00 Casting in, on, or around objects which form part of the product B22D23/04 takes precedence; alumino-thermic welding B23K23/00; coating by casting molten material on the substrate C23C6/00
• CPC Class Codes: B22F 7/06 of composite workpieces or articles from parts, e.g. to form tipped tools B22F7/002 takes precedence
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G01S 13/78 discriminating between different kinds of targets, e.g. IFF-radar, i.e. identification of friend or foe G01S13/75, G01S13/79 take precedence
• 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 19/073 Special arrangements for circuits, e.g. for protecting identification code in memory protection against unauthorised use of computer memory G06F12/14
• 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 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 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10217 parameter settings controlling the transmission power of the interrogator
• CPC Class Codes: G06K 7/10861 sensing of data fields affixed to objects or articles, e.g. coded labels postal sorting B07C3/14, conveying articles B65G47/48
• 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
• CPC Class Codes: G08B 13/1427 with transmitter-receiver for distance detection
• CPC Class Codes: G08B 13/149 with electric, magnetic, capacitive switch actuation
• CPC Class Codes: G08B 21/0286 Tampering or removal detection of the child unit from child or article
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2225 : used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/38 : formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 9/28 : Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00
• CPC Class Codes: H01Q 9/285 : Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407
• CPC Class Codes: H04L 2101/604 : Address structures or formats
• CPC Class Codes: H04L 2101/622 : Layer-2 addresses, e.g. medium access control [MAC] addresses
• CPC Class Codes: H04L 61/5038 : for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 61/5046 : Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092
• CPC Class Codes: H04L 61/5069 : for group communication, multicast communication or broadcast communication
• CPC Class Codes: H04L 61/5084 : Providing for device mobility network addressing or numbering for mobility support in wireless networks H04W8/26; mobile IP H04W80/04
• CPC Class Codes: H04L 61/5092 : by self-assignment, e.g. picking addresses at random and testing if they are already in use

Abstract

A method of adjusting the 2-way communication range of an RFID system to assist a human operator to individually handle and interrogate a plurality of tagged objects, such as suitcases, that each include an RFID tag transceiver. An RFID interrogator transceiver is mounted on the human operator. The 2-way communication range between the interrogator transceiver and the tag transceivers is adjusted to only slightly exceed the closest distance between the interrogator and the tag while the operator is handling the tagged object. Preferably, the 2-way communication range is short enough that other tagged objects will remain outside the communication range and will not respond to messages from the interrogator. Another aspect of the invention is a method of verifying whether an object to be transported has reached its intended destination. In this aspect, an interrogator transceiver at a first destination interrogates an RFID tag transceiver on the object, and in response the tag transmits its intended destination.

Claims

1-27. -27. (canceled).

28. A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, comprising the steps of:

mounting on the person an RFID interrogator transceiver having an antenna;

mounting on each tagged object an RFID tag transceiver, wherein

each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and

the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers; and

adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects only slightly exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and the tag transceiver mounted on that tagged object.

29. A method in accordance with claim 28 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.

30. A method in accordance with claim 29 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.

31. A method in accordance with claim 28, wherein the adjusting further comprises adjusting said at least one of the performance parameters so that said reliable two-way communications range is short enough so that, when the person handles a tagged object, no other tagged object is within either reliable or unreliable two-way communication range of the interrogator.

32. A method in accordance with claim 28, wherein:

the performance parameters of each tag transceiver include a receiver sensitivity of the tag transceiver;

the performance parameters of the interrogator transceiver include a receiver sensitivity of the interrogator transceiver and a transmitter output power of the interrogator transceiver; and

the adjusting step includes adjusting at least one of the receiver sensitivity of the tag transceiver, the receiver sensitivity of the interrogator transceiver, and the transmitter output power of the interrogator transceiver.

33. A method in accordance with claim 28, wherein each tag transceiver is a modulated backscatter transceiver.

34. A method in accordance with claim 28, further comprising the steps of:

the interrogator transceiver transmitting an interrogation message while the person is close enough to a tagged object for the antenna of the interrogator transceiver and that transceiver of the tagged object to be within the communications range;

the transceiver of that tagged object transmitting, in response to the interrogation message, an identification message containing data identifying that tagged object; and

the interrogator transceiver receiving the identification message and presenting the data to said person.

35. A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, comprising the steps of:

mounting on the person an RFID interrogator transceiver having an antenna;

mounting on each tagged object an RFID tag transceiver, wherein

each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and

the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers; and

adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and the tag transceiver mounted on that tagged object;

wherein the adjusting step further comprises adjusting said at least one of the performance parameters so that said reliable two-way communications range is short enough so that, when the person handles a tagged object, no other tagged object being handled by any other person is within reliable two-way communication range of the interrogator.

36. A method in accordance with claim 35 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.

37. A method in accordance with claim 36 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.

38. A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, comprising the steps of:

mounting on the person an RFID interrogator transceiver having an antenna;

mounting on each tagged object an RFID tag transceiver, wherein

each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and

the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers; and

adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and the tag transceiver mounted on that tagged object;

wherein the adjusting step further comprises adjusting said at least one of the performance parameters so that said reliable two-way communications range is short enough so that, when the person handles a tagged object, no other tagged object is within reliable two-way communication range of the interrogator.

39. A method in accordance with claim 38 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.

40. A method in accordance with claim 39 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.

41. A method of adjusting the two-way communication range of an RFID system to permit a person to individually handle and interrogate each one of a plurality of tagged objects, each tagged object having an RFID tag transceiver, comprising the steps of:

mounting adjacent the person an RFID interrogator transceiver having an antenna;

mounting on each tagged object an RFID tag transceiver, wherein

each tag transceiver is characterized by a set of one or more performance parameters which control a reliable two-way communications range between that tag transceiver and the interrogator transceiver, and

the interrogator transceiver is characterized by a set of one or more performance parameters which control the reliable two-way communications range between the interrogator transceiver and any of the tag transceivers; and

adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceiver of each of the tagged objects only slightly exceeds the closest distance, during times when the person handles that tagged object, between the antenna of the interrogator and that tagged object.

42. A method in accordance with claim 41, wherein the step of mounting the interrogator transceiver further comprises:

mounting the interrogator transceiver on the person so as to leave the hands of the person free to grasp objects other than the interrogator transceiver.

43. An RFID interrogator apparatus having an adjustable two-way communication range so as to permit a person to individually interrogate the closest one of a plurality of nearby tagged objects, wherein each tagged object has a respective RFID tag transceiver attached thereto, comprising:

an RFID interrogator transceiver, configured to communicate with any of the RFID tag transmitters, including a transmitter and receiver and having adjustable transmitter power and adjustable receiver sensitivity;

an antenna coupled to the interrogator transceiver and which is adapted for mounting on a person; and

a control logic circuit, connected to the interrogator transceiver, for adjusting at least one of interrogator transmitter power and interrogator receiver sensitivity so that the reliable communications range between the interrogator transceiver and the tag transceivers only slightly exceeds the closest distance, during times when said person handles a tagged object, between the antenna and the tag transceiver attached to that tagged object.

44. A method in accordance with claim 43 wherein adjusting at least one of the interrogator transmitter power and interrogator receiver sensitivity comprises adjusting interrogator transmitter output power.

45. A method in accordance with claim 44 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.

46. An RFID interrogator apparatus having an adjustable two-way communication range so as to permit a person to individually interrogate the closest one of a plurality of nearby tagged objects, wherein each tagged object has a respective RFID tag transceiver attached thereto, comprising:

an RFID interrogator transceiver characterized by a set of one or more performance parameters which control a reliable two-way communications range between the interrogator transceiver and any of the RFID tag transceivers;

an antenna coupled to the interrogator transceiver and which is adapted for mounting on a person; and

a control logic circuit, connected to the interrogator transceiver, for adjusting at least one of the interrogator performance parameters so that the reliable two-way communications range between the interrogator transceiver and the tag transceivers exceeds the closest distance, during times when said person handles a tagged object, between the antenna and the tag transceiver attached to that tagged object;

wherein the control logic circuit adjusts said at least one of the interrogator performance parameters so that said reliable two-way communications range is short enough so that, when said person handles a tagged object, no other tagged object being handled by any other person is within reliable two-way communication range of the interrogator transceiver.

47. A method in accordance with claim 46 wherein adjusting at least one of the interrogator performance parameters comprises adjusting interrogator transmitter output power.

48. A method in accordance with claim 47 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.

49. An RFID interrogator apparatus having an adjustable two-way communication range so as to permit a person to individually interrogate the closest one of a plurality of nearby tagged objects, wherein each tagged object has a respective RFID tag transceiver attached thereto, comprising:

an RFID interrogator, configured to communicate with RFID tag transmitters, including a transmitter and receiver and having adjustable transmitter power and adjustable receiver sensitivity;

an antenna coupled to the interrogator transceiver and which is adapted for mounting on a person; and

a control logic circuit, connected to the interrogator transceiver, for adjusting at least one of interrogator transmitter power and interrogator receiver sensitivity so that the reliable two-way communications range between the interrogator transceiver and the tag transceivers exceeds the closest distance, during times when said person handles a tagged object, between the antenna and the tag transceiver attached to that tagged object;

wherein the control logic circuit adjusts said at least one of interrogator transmitter power and interrogator receiver sensitivity so that said reliable two-way communications range is short enough so that, when said person handles a tagged object, no other tagged object is within reliable two-way communication range of the interrogator transceiver.

50. A method in accordance with claim 49 wherein adjusting at least one of the interrogator transmitter power and interrogator receiver sensitivity comprises adjusting interrogator transmitter output power.

51. A method in accordance with claim 50 wherein interrogator transmitter output power is selectable from among at least three different possible power levels.