Method of addressing messages and communications system
First Claim
1. A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising utilizing a tree search method in an arbitration scheme to be able to establish one-on-one communications between the interrogator and individual ones of the multiple wireless identification devices, a search tree being defined for the tree search method, the tree having multiple levels respectively representing subgroups of the multiple wireless identification devices, the method further comprising starting the tree search at a selectable level of the search tree.
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Accused Products
Abstract
A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising utilizing a tree search method to establish communications without collision between the interrogator and individual ones of the multiple wireless identification devices, a search tree being defined for the tree search method, the tree having multiple levels respectively representing subgroups of the multiple wireless identification devices, the method further comprising starting the tree search at a selectable level of the search tree. A communications system comprising an interrogator, and a plurality of wireless identification devices configured to communicate with the interrogator in a wireless fashion, the respective wireless identification devices having a unique identification number, the interrogator being configured to employ a tree search technique to determine the unique identification numbers of the different wireless identification devices so as to be able to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision by multiple wireless identification devices attempting to respond to the interrogator at the same time, wherein the interrogator is configured to start the tree search at a selectable level of the search tree.
79 Citations
41 Claims
- 1. A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising utilizing a tree search method in an arbitration scheme to be able to establish one-on-one communications between the interrogator and individual ones of the multiple wireless identification devices, a search tree being defined for the tree search method, the tree having multiple levels respectively representing subgroups of the multiple wireless identification devices, the method further comprising starting the tree search at a selectable level of the search tree.
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7. A method of addressing messages from an interrogator to a selected one or more of a number of communications devices, the method comprising:
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establishing a first predetermined number of bits to be used as unique identification numbers, and establishing for respective devices unique identification numbers respectively having the first predetermined number of bits; establishing a second predetermined number of bits to be used for random values; causing the devices to select random values, wherein respective devices choose random values independently of random values selected by the other devices; determining the maximum number of devices potentially capable of responding to the interrogator; transmitting a command from the interrogator requesting devices having random values within a specified group of random values to respond, the specified group being chosen in response to the determined maximum number; receiving the command at multiple devices, devices receiving the command respectively determining if the random value chosen by the device falls within the specified group and, if so, sending a reply to the interrogator; and determining using the interrogator if a collision occurred between devices that sent a reply and, if so, creating a new, smaller, specified group. - View Dependent Claims (8, 9, 10, 11)
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12. A method of addressing messages from an interrogator to a selected one or more of a number of communications devices, the method comprising:
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establishing unique identification numbers for respective devices; causing the devices to select random values, wherein respective devices choose random values independently of random values selected by the other devices; transmitting a command from the interrogator requesting devices having random values within a specified group of a plurality of possible groups of random values to respond, the specified group being less than the entire set of random values, the plurality of possible groups being organized in a binary tree defined by a plurality of nodes at respective levels, wherein the size of groups of random values decrease in size by half with each node descended, wherein the specified group is below a node on the tree selected based on the maximum number of devices capable of communicating with the interrogator; receiving the command at multiple devices, devices receiving the command respectively determining if the random value chosen by the device falls within the specified group and, if so, sending a reply to the interrogator; and
, if not, not sending a reply; anddetermining using the interrogator if a collision occurred between devices that sent a reply and, if so, creating a new, smaller, specified group by descending in the tree. - View Dependent Claims (13, 14, 15, 16)
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17. A method of addressing messages from an interrogator to a selected one or more of a number of RFID devices, the method comprising:
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establishing for respective devices unique identification numbers respectively having a first predetermined number of bits, the first predetermined number being a multiple of sixteen; establishing a second predetermined number of bits to be used for random values, the second predetermined number being a multiple of sixteen; causing the devices to select random values, wherein respective devices choose random values independently of random values selected by the other devices; transmitting a command from the interrogator requesting devices having random values within a specified group of a plurality of possible groups of random values to respond, the specified group being equal to or less than the entire set of random values, the plurality of possible groups being organized in a binary tree defined by a plurality of nodes at respective levels, wherein the maximum size of groups of random values decrease in size by half with each node descended, wherein the specified group is below a node on a level of the tree selected based on the maximum number of devices known to be capable of communicating with the interrogator; receiving the command at multiple devices, devices receiving the command respectively determining if the random value chosen by the device falls within the specified group and, only if so, sending a reply to the interrogator, wherein sending a reply to the interrogator comprises transmitting both the random value of the device sending the reply and the unique identification number of the device sending the reply; using the interrogator to determine if a collision occurred between devices that sent a reply and, if so, creating a new, smaller, specified group using a level of the tree different from the level used in the interrogator transmitting, the interrogator transmitting a command requesting devices having random values within the new specified group of random values to respond; and if a reply without collision is received from a device, the interrogator subsequently sending a command individually addressed to that device. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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- 26. A communications system comprising an interrogator, and a plurality of wireless identification devices configured to communicate with the interrogator in a wireless fashion, the respective wireless identification devices having a unique identification number, the interrogator being configured to employ a tree search technique to determine the unique identification numbers of the different wireless identification devices so as to be able to establish one-on-one communications between the interrogator and individual ones of the multiple wireless identification devices wherein the interrogator is configured to start the tree search at a selectable level of the search tree.
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29. A system comprising:
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an interrogator; a number of communications devices capable of wireless communications with the interrogator; means for establishing a first predetermined number of bits to be used as unique identification numbers, and for establishing for respective devices unique identification numbers respectively having the first predetermined number of bits; means for establishing a second predetermined number of bits to be used for random values; means for causing the devices to select random values, wherein respective devices choose random values independently of random values selected by the other devices; means for inputting a predetermined number indicative of the maximum number of devices possibly capable of communicating with the receiver; means for causing the interrogator to transmit a command requesting devices having random values within a specified group of random values to respond, the specified group being chosen in response to the predetermined number; means for causing devices receiving the command to determine if their chosen random values fall within the specified group and, if so, send a reply to the interrogator; and means for causing the interrogator to determine if a collision occurred between devices that sent a reply and, if so, create a new, smaller, specified group. - View Dependent Claims (30, 31, 32, 33)
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34. A system comprising:
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an interrogator configured to communicate to a selected one or more of a number of communications devices; a plurality of communications devices; the devices being configured to select random values, wherein respective devices choose random values independently of random values selected by the other devices; the interrogator being configured to transmit a command requesting devices having random values within a specified group of a plurality of possible groups of random values to respond, the specified group being less ii than the entire set of random values, the plurality of possible groups being organized in a binary tree defined by a plurality of nodes at respective levels, wherein the size of groups of random values decrease in size by half with each node descended, wherein the specified group is below a node on the tree selected based on a predetermined maximum number of devices capable of communicating with the interrogator; devices receiving the command being configured to respectively determine if their chosen random values fall within the specified group and, if so, send a reply to the interrogator; and
, if not, not send a reply; andthe interrogator being configured to determine if a collision occurred between devices that sent a reply and, if so, create a new, smaller, specified group by descending in the tree. - View Dependent Claims (35, 36, 37)
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38. A system comprising:
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an interrogator configured to communicate to a selected one or more of a number of RFID devices; a plurality of RFID devices, respective devices being configured to store unique identification numbers respectively having a first predetermined number of bits, the first predetermined number being an integer multiple of sixteen, respective devices being further configured to store a second predetermined number of bits to be used for random values, the second predetermined number being an integer multiple of sixteen, respective devices being configured to select random values independently of random values selected by the other devices; the interrogator being configured to transmit an identify command requesting a response from devices having random values within a specified group of a plurality of possible groups or random values, the specified group being less than or equal to the entire set of random values, the plurality of possible groups being organized in a binary tree defined by a plurality of nodes at respective levels, wherein the maximum size of groups of random values decrease in size by half with each node descended, wherein the specified group is below a node on a level of the tree selected based on a predetermined number based on the maximum number of devices known to be capable of communicating with the interrogator; devices receiving the command respectively being configured to determine if their chosen random values fall within the specified group and, only if so, send a reply to the interrogator, wherein sending a reply to the interrogator comprises transmitting both the random value of the device sending the reply and the unique identification number of the device sending the reply; the interrogator being configured to determine if a collision occurred between devices that sent a reply and, if so, create a new, smaller, specified group using a level of the tree different from the level used in previously transmitting an identify command, the interrogator transmitting an identify command requesting devices having random values within the new specified group of random values to respond; and the interrogator being configured to send a command individually addressed to a device after communicating with a device without a collision. - View Dependent Claims (39, 40, 41)
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Specification