System and method for radio frequency tag group select

• US 7,158,046 B2
• Filed: 11/02/2004
• Issued: 01/02/2007
• Est. Priority Date: 09/09/1994
• Status: Expired due to Fees

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Goldman, Kenneth Alan, McAuliffe, Kevin P., Cofino, Thomas A., Cesar, Christian Lenz, Greene, Sharon Louise, Heinrich, Harley Kent, Chan, Shun-Shing
• Primary Examiner(s): Garber; Wendy R.
• Assistant Examiner(s): YANG, CLARA I
• Application Number:
  US10/979,866
• Publication Number:
  US 20050168348A1
• Time in Patent Office: 791 Days
• Field of Search: 340/825.69, 340/825.71, 340/3.51, 340/3.52, 710/111
• US Class Current: 370/313
• CPC Class Codes: G05B 19/0421 Multiprocessor system
• CPC Class Codes: G05B 2219/2231 Master slave
• CPC Class Codes: G05B 2219/25277 Tristate
• 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 7/10108 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: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 2201/20 Binding and programming of remote control devices

Abstract

A master entity is capable of broadcasting commands to slaves which move to another state when they satisfy a primitive condition specified in the command. By moving slaves among three sets, a desired subset of slaves can be isolated in one of the sets. This desired subset of slaves ten can be moved to one of the states that is unaffected by commands that cause the selection of other desirable subsets of slaves. In the incorporated U.S. Pat. Nos. 5,550,547 and 5,673,037, certain subgroups of radio frequency tags are selected for querying, communicating, and/or identifying by commands from a base station.

Claims

1. A systems for selecting a subset of slaves that satisfy a selection criterion and then isolating the selected subset from further participation in a selection and isolating process, said system comprising:

a master unit for communicating a selection criterion command to a plurality of slaves, the selection criterion command representing the selection criterion;

each slave of said plurality of slaves being in one of three or more different possible states during the selection and isolating process;

a memory in said each slave containing at least one information value for use in evaluation of a selection criterion;

a receiving unit in said each slave for receiving the selection criterion command from the master unit;

a processing unit in said each slave that processes the selection criterion command by moving the slave from a first state to a second state if and only if the slave is already in the first state and the at least one information value satisfies the selection criterion;

whereby said each slave is deemed to be selected if said each slave is in the second state after the processing unit in said each slave has processed the selection criterion command; and

moving slaves in the second state to a third state so as to be unaffected by further selection criterion commands.

2. A system as in claim 1, where the master unit is a base station, the staves are radio frequency tags, and the base station communicates with the radio frequency tags with a wireless radio frequency signal.

3. A method for selecting a subset of slaves that satisfy a selection criterion and then causing the selected subset of slaves to be isolated from further participation in a selecting and isolating process, said method comprising;

storing at least one information value in each of a plurality of slaves for use in evaluating a selection criterion;

representing a selection criterion as a selection criterion command;

communicating the selection criterion command to the plurality of slaves, each slave of said plurality of slaves being in one of three or more difference states during the selecting and isolating process;

processing the selection criterion command at said each slave by moving said each slave from a first state to a second state if and only if the slave is already in the first state and the at least one information value satisfies the selection criterion;

then

deeming said each slave in the second state to be selected; and

moving the slaves in the second state to a third state so as to be unaffected by further selection criterion commands.

4. A method, as in claim 3, wherein the selection criterion command is communicated as a wireless radio frequency signal, and the slaves are radio frequency transponders.

5. A state machine slave for responding to a selection criterion command from a master unit, and when selected being isolated from further participation in a selection and isolating process, said state machine slave comprising;

first, second and third states;

a memory containing at least one information value for evaluating a selection criterion;

a receiving unit for receiving a selection criterion command representing a selection criterion;

a processing unit that process the selection criterion command by moving the slave from a first state to a second state if and only if the slave is already in the first state and the at least one information value satisfies the selection criterion;

whereby the slave is deemed to be selected if the slave is in the second state after the processing unit has processed the selection criterion command; and

the slave being movable from the second state to the third state so as to be unaffected by further selection criterion commands.

6. A state machine stave, as in claim 5, where the slave is a radio frequency transponder, and the receiving unit receives the selection criterion command as a wireless radio frequency signal.