Methods and apparatus for anti-collision for radio frequency communication
First Claim
1. An anti-collision method for radio frequency (RF) communication, said method comprising:
- detecting by a first device an interfering RF field of a second device, the first device being in a quiescent mode; and
entering an active mode by the first device after detecting an absence of the RF field of the second device for an interval of time and after a pseudo-random delay period.
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Accused Products
Abstract
An identification system includes a reader and one or more tags. The reader identifies tags such as radio frequency (RF) tags. The system divides a number space into n bins, wherein each bin is associated with m unique bits of the number space, and the number space contains the identification codes of the tags. A command is issued to test v bits of the number space. A response is received from a tag, wherein the response occurs when a first portion of an identification code of the tag matches the v bits of the number space, a timing of the response corresponds to a particular bin and m unique bits associated with the particular bin correspond to a second portion of the identification code.
106 Citations
57 Claims
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1. An anti-collision method for radio frequency (RF) communication, said method comprising:
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detecting by a first device an interfering RF field of a second device, the first device being in a quiescent mode; and
entering an active mode by the first device after detecting an absence of the RF field of the second device for an interval of time and after a pseudo-random delay period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An anti-collision method for radio frequency (RF) communication, said method comprising:
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determining by a device an absence of an interfering RF field for an interval of time, the device being in a quiescent mode during the interval of time and a pseudo-random delay period; and
entering an active mode by the device after the pseudo-random delay period, wherein the device in the quiescent mode transmits at less than approximately 10% of a maximum RF power level. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. An anti-collision method for radio frequency (RF) communication, said method comprising:
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listening by a device for an absence of an interfering RF field for an interval of time, the device being in a quiescent mode during the interval of time and a pseudo-random delay period; and
entering an active mode by the device after the pseudo-random delay period, wherein the device in the quiescent mode transmits less than approximately 10% of a maximum RF power level, and wherein the device is used for a purchase of a product.
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20. A reader to identify tags, comprising:
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a receiver to detect a presence and absence of an interfering RF field of another reader; and
a transmitter configured to operate in a quiescent mode when the receiver detects the presence of the interfering RF field and, after detecting the absence of the interfering RF field for an interval of time, to enter an active mode after a pseudo-random delay. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A reader configured to avoid RF collisions with other readers, comprising:
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a receiver configured to determine an absence of an interfering RF field for an interval of time;
a transmitter configured to operate in a quiescent mode during the interval of time and a pseudo-random delay period, to transmit in the quiescent mode at less than approximately 10% of a maximum RF power level, and to enter an active mode after the pseudo-random delay period; and
a processor to control data communications between the transmitter, the receiver and a tag. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37)
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38. An anti-collision reader for radio frequency (RF) communication, comprising:
a transceiver configured to listen for an absence of an interfering RF field for an interval of time, wherein the transceiver is configured to operate in a quiescent mode during the interval of time and a pseudo-random delay period, wherein the transceiver in the quiescent mode is configured to transmit at less than approximately 10% of a maximum RF power level, wherein the transceiver is configured to enter an active mode after the pseudo-random delay period, and wherein the reader is used for a purchase of a product.
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39. A machine-readable medium including instructions that, when read by a machine, cause the machine to perform anti-collision operations in radio-frequency (RF) data communications, comprising:
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detecting by a first device an interfering RF field of a second device, the first device being in a quiescent mode; and
entering an active mode by the first device after detecting an absence of the RF field of the second device for an interval of time and after a pseudo-random delay period. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A machine-readable medium including instructions that, when read by a machine, cause the machine to perform anti-collision in radio-frequency (RF) data communications, comprising:
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determining by a device an absence of an interfering RF field for an interval of time, the device being in a quiescent mode during the interval of time and a pseudo-random delay period; and
entering an active mode by the device after the pseudo-random delay period, wherein the device in the quiescent mode transmits at less than approximately 10% of a maximum RF power level. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56)
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57. A machine-readable medium including instructions that, when read by a machine, cause the machine to perform anti-collision in radio-frequency (RF) data communications, comprising:
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listening by a device for an absence of an interfering RF field for an interval of time, the device being in a quiescent mode during the interval of time and a pseudo-random delay period; and
entering an active mode by the device after the pseudo-random delay period, wherein the device in the quiescent mode transmits less than approximately 10% of a maximum RF power level, and wherein the device is used for a purchase of a product.
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Specification