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.
2 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 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 includes: receiving a first signal from an interrogator in accordance with an algorithm to identify a radio frequency identification (RFID) device in a field of the interrogator, the first signal comprising a first set of bits and requesting a response from one or more RFID devices in the field selected in accordance with at least the first set of bits; responsive to receiving the first signal, determining if the first set of bits is equal to a first portion of an identifier of the RFID device, and, if so, modulating a radio frequency (RF) field, provided by the interrogator, to communicate a reply to the interrogator in accordance with the algorithm and receiving, in accordance with the algorithm, a retransmission of the first signal from the interrogator in response to the interrogator receiving the reply without detecting a collision.
71 Citations
153 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 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 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 at multiple devices, devices receiving the communication respectively determining if the random value chosen by the device falls within the specified group and, if so, sending a reply to the transponder; and
, if not, not sending a reply; anddetermining 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; andif 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; andthe 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, comprising:
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receiving a first signal from an interrogator in accordance with an algorithm to identify a radio frequency identification (RFID) device in a field of the interrogator, the first signal having associated therewith a first set of bits and requesting a response from one or more RFID devices in the field selected in accordance with at least the first set of bits; responsive to receiving the first signal, determining if the first set of bits matches a first portion of an identifier of the RFID device, and, if so, modulating a radio frequency (RF) field, provided by the interrogator, to communicate a reply to the interrogator in accordance with the algorithm; and receiving, in accordance with the algorithm, another transmission of the first signal from the interrogator in response to the interrogator receiving the reply without detecting a collision. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 94, 95, 96, 97, 98, 99, 100, 101)
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52. A system, comprising:
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a radio frequency identification (RFID) device comprising a receiver to receive a first command including a portion of an identification number, memory to store an identifier of the device, and a transmitter to communicate a reply to the first command if the portion of the identification number matches a first portion of the identifier; and an interrogator configured to implement an algorithm to identify one or more RFID devices in a field of the interrogator, the algorithm comprising transmitting a first signal with a first set of bits to request a response from a selected one or more devices, receiving a first response thereto from the selected one or more devices, detecting if a collision occurred in the first response, and retransmitting the first signal with at least the first set of bits to request a second response from at least one of the selected one or more devices in response to detecting no collision in the first response. - View Dependent Claims (53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. An apparatus for wirelessly reading at least one radio frequency identification (RFID) device, comprising:
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a transmitter to transmit a command along with a first portion of a set of identifiers to request a response from at least one RFID device that has an identifier in the set; an antenna to provide a radio frequency (RF) field to be modulated by the device; a receiver to receive the response; and processing circuitry to perform collision detection, to determine the identifier using the response, and to cause the transmitter to retransmit the command along with at least the first portion of the set of identifiers responsive to detecting no collision in the response. - View Dependent Claims (72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93)
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102. Wireless apparatus, comprising:
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first apparatus configured to receive a command signal from an interrogator in accordance with an algorithm to identify a radio frequency identification (RFID) device in a field of the interrogator, the first command comprising a first set of bits and requesting a response from one or more RFID devices in the field selected in accordance with at least the first set of bits; and logic configured to, responsive to receiving the first command, determine whether the first set of bits matches a first portion of an identifier of the RFID device; and a second apparatus configured to modulate a radio frequency (RF) field provided by the interrogator in order to communicate a reply to the interrogator in accordance with the algorithm; wherein said first apparatus is further configured to receive a second transmission of the first command from the interrogator in response to the interrogator receiving the reply without detecting a collision; and wherein said communication of the reply is performed based at least in part on said determination of whether the first set of bits matches a first portion of an identifier of the RFID device. - View Dependent Claims (103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117)
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118. A method for wirelessly reading at least one radio frequency identification (RFID) device, comprising:
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transmitting a command along with a first portion of a set of identifiers to request a response from the at least one RFID device that has an identifier in the set, the command being transmitted via an antenna configured to provide a radio frequency (RF) field to be modulated by the least one RFID device; receiving the response; and performing collision detection to determine the identifier using the response, and to cause the transmitter to transmit the command a second time along with at least the first portion of the set of identifiers responsive to detecting no collision. - View Dependent Claims (119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 144)
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140. A method of wireless communication of data, comprising:
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receiving a first signal from an interrogator in accordance with an algorithm to identify a radio frequency identification (RFID) device in a field of the interrogator, the first signal comprising a first set of bits and requesting a response from the RFID device in the field selected in accordance with at least the first set of bits; responsive to receiving the first signal; determining if the first set of bits matches a predefined value related to the RFID device; and if so, modulating a radio frequency (RF) field, provided by the interrogator, to communicate a first reply to the interrogator in accordance with the algorithm; and receiving, in accordance with the algorithm, a retransmission from the interrogator of at least a portion of the first reply, in response to the interrogator receiving the first reply without detecting a collision; wherein the first signal further comprises slot information useful for issuing said first reply by said RFID device. - View Dependent Claims (141, 142, 143, 145, 146, 147, 148, 149, 150, 151, 152, 153)
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Specification