Method of addressing messages and communications system
First Claim
1. A method of establishing wireless communications between an interrogator and wireless identification devices, the method comprising utilizing a tree search technique to establish communications, without collision, between the interrogator and individual ones of the multiple wireless identification devices, the method including using a search tree having multiple nodes respectively representing subgroups of the multiple wireless identification devices, the method further comprising, for a node, transmitting a command, using the interrogator, requesting that devices within the subgroup represented by the node respond, determining with the interrogator if a collision occurred in response to the command and, if not, repeating the command at the same node.
4 Assignments
0 Petitions
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 attempt to identify individual ones of the multiple wireless identification devices so as to be able to perform 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 nodes respectively representing subgroups of the multiple wireless identification devices, wherein the interrogator transmits a command at a node, requesting that devices within the subgroup represented by the node respond, wherein the interrogator determines if a collision occurs in response to the command and, if not, repeats the command at the same node. An interrogator configured to transmit a command at a node, requesting the devices within the subgroup represented by the node respond, the interrogator further being configured to determine if a collision occurs in response to the command and, if not, to repeat the command at the same node.
85 Citations
60 Claims
- 1. A method of establishing wireless communications between an interrogator and wireless identification devices, the method comprising utilizing a tree search technique to establish communications, without collision, between the interrogator and individual ones of the multiple wireless identification devices, the method including using a search tree having multiple nodes respectively representing subgroups of the multiple wireless identification devices, the method further comprising, for a node, transmitting a command, using the interrogator, requesting that devices within the subgroup represented by the node respond, determining with the interrogator if a collision occurred in response to the command and, if not, repeating the command at the same node.
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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 for respective devices unique identification numbers;
causing the devices to select random values, wherein respective devices choose random values independently of random values selected by the other devices;
transmitting a communication, from the interrogator, requesting devices having random values within a first specified group of random values to respond;
receiving the communication at multiple devices, devices receiving the communication respectively determining if the random value chosen by the device falls within the first 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 second specified group smaller than the first specified group; and
, if not, again transmitting a communication requesting devices having random values within the first specified group of random values to respond. - View Dependent Claims (8, 9, 10)
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11. A method of addressing messages from a transponder to a selected one or more of a number of communications device, 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 communication from the transponder requesting devices having random values within a specified group of a plurality of possible groups of random values to respond, the plurality of possible groups being organized in a binary tree defined by a plurality of nodes at respective levels, the specified group being defined as being at one of the nodes;
receiving the communication command at multiple devices, devices receiving the communication command respectively determining if the random value chosen by the device falls within the specified group and, if so, sending a reply to the transponder interrogator;
and, if not, not sending a reply; and
determining using the transponder if a collision occurred between devices that sent a reply and, if so, creating a new, smaller, specified group by descending in the tree; and
, if not, transmitting a communication at the same node. - View Dependent Claims (12, 13)
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14. 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;
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 using 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;
receiving the command at multiple RFID devices, RFID devices receiving the command respectively determining if their chosen random values fall within the specified group and, only if so, sending a reply to the interrogator, wherein sending a reply to the interrogator comprises transmitting the unique identification number of the device sending the reply;
determining using the interrogator if a collision occurred between devices that sent a reply and, if so, creating a new, smaller, specified group using a different level of the tree, the interrogator transmitting a command requesting devices having random values within the new specified group of random values to respond; and
, if not, the interrogator re-transmitting a command requesting devices having random values within the first mentioned 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 (15, 16, 17, 18, 19, 20)
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- 21. A communications system comprising an interrogator, and a plurality of wireless identification devices configured to communicate with the interrogator using RF, the interrogator being configured to employ tree searching to attempt to identify individual ones of the multiple wireless identification devices, so as to be able to perform communications without collision between the interrogator and individual ones of the multiple wireless identification devices, the interrogator being configured to follow a search tree, the tree having multiple nodes respectively representing subgroups of the multiple wireless identification devices, the interrogator being configured to transmit a command at a node, requesting that devices within the subgroup represented by the node respond, the interrogator further being configured to determine if a collision occurs in response to the command and, if not, to repeat the command at the same node.
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27. A system comprising:
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an interrogator;
a number of communications devices capable of wireless communications with the interrogator;
means for establishing for respective devices unique identification numbers respectively having the first predetermined number of bits;
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 causing the interrogator to transmit a command requesting devices having random values within a specified group of random values to respond;
means for causing devices receiving the command to determine if their chosen random values fall within the specified group and, if so, to 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, to create a new, smaller, specified group; and
, if not, transmit a command requesting devices having random values within the same specified group of random values to respond. - View Dependent Claims (28, 29, 30)
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31. A system comprising:
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an interrogator configured to communicate to a selected one or more of a number of communications devices; and
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 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, the specified group being defined as being at one of the nodes;
devices receiving the command being configured to respectively 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 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 different level of the tree, the interrogator being configured to transmit a command requesting devices having random values within the new specified group of random values to respond; and
, if not, the interrogator being configured to re-transmit a command requesting devices having random values within the first mentioned specified group of random values to respond. - View Dependent Claims (32, 33, 34)
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35. 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 a unique identification number, respective devices being further configured to store a random value;
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 plurality of possible groups being organized in a binary tree defined by a plurality of nodes at respective levels, the specified group being defined as being at one of the nodes;
devices receiving the command respectively being configured to 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; and
the interrogator being configured to determine if a collision occurred between devices that sent a reply and, if so, to create a new, smaller, specified group by descending in the tree; and
, if not, to transmit a command at the same node. - View Dependent Claims (36, 37, 38)
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39. A method of establishing wireless communications between an interrogator and wireless identification devices, the method comprising:
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transmitting a first interrogation command, using the interrogator, to a first plurality of wireless identification devices, said command requesting that devices receiving the command respond to the interrogator;
detecting with the interrogator if a collision occurred in response to the interrogation command;
sending an interrogation command to at least a portion of said first plurality of wireless identification devices until no collision is detected; and
once no collision is detected, sending another interrogation command to at least a portion of said first plurality of wireless identification devices. - View Dependent Claims (40, 41, 42, 43)
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44. A method of establishing wireless communications between an interrogator and wireless identification devices, the method comprising:
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transmitting a first interrogation command, using the interrogator, to a first plurality of wireless identification devices, said command requesting that devices receiving the command respond to the interrogator;
detecting if a collision occurred in response to the interrogation command;
in the event of detection of a collision, sending a signal to at least one wireless identification device to avoid a subsequent collision;
sending an interrogation command to at least a portion of said first plurality of wireless identification devices until no collision is detected; and
once no collision is detected, sending another interrogation command to said first plurality of wireless identification devices.
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45. A method comprising:
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performing arbitration including sending a first command from an interrogator to a plurality of wireless identification devices;
receiving a good reply from a first wireless identification device of the plurality of wireless identification devices in response to the first command;
sending a second command from the interrogator to silence the first wireless identification device; and
resending the first command from the interrogator to the plurality of wireless identification devices. - View Dependent Claims (46, 47, 48, 49)
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50. An arbitration method comprising:
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sending a first command from an interrogator to a plurality of wireless identification devices;
receiving a reply from a first wireless identification device of the plurality of wireless identification devices, and detecting no collisions, in response to the first command; and
resending the first command from the interrogator to the plurality of wireless identification devices in response to receiving the reply and detecting no collisions. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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Specification