US6034603A
Expired / Lapsed
US
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Radio tag system and method with improved tag interference avoidance
Assignee: Axcess International Inc
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Filing: 1997-01-24
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Granted: 2000-03-07
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Expires: 2017-01-24
Abstract
Abstract A data transmission system includes a reader transceiver and one or more tag transceivers. The reader transmits an activation signal to a tag. The tag selectively transmits a response signal to the reader at a specific time determined by a detected level of communications channel activity. The detector operates in a low-power standby state until the time it receives the activation signal, and then operates in an active state. The invention further incorporates a technique to maintain an extremely low power state to the tag during quiescent mode while retaining full sensitivity to reader activation signals. The reader transceivers are of a modular architecture with each module operating independently, yet in concert with the others. The modules are interconnected in a media independent method and can interact remotely with other modules.
Inventors
- 👤 Wayne E. Steeves
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:22
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10009; G06K7/10019; G06K7/10029; G06K7/10039; G06K7/0008; G06K7/10316; G06K7/10356
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
74 words
A tag transceiver, comprising: a receiver module operable to listen for radio frequency activity; a processor module operable to detect radio frequency activity, to determine an amount of radio frequency activity during a period of time based on detected radio frequency activity during a plurality of sub-periods of the period, and to initiate transmission of a signal based on the amount of radio frequency activity; and a transmitter module operable to transmit the signal.
Claim 2
Dependent Claim
74 words
A tag transceiver, comprising: a receiver module operable to listen for radio frequency activity; a processor module operable to detect radio frequency activity, to determine an amount of radio frequency activity during a period of time based on detected radio frequency activity during a plurality of sub-periods of the period, and to initiate transmission of a signal based on the amount of radio frequency activity; and a transmitter module operable to transmit the signal.
Claim 3
Dependent Claim
37 words
The tag transceiver of claim 1, wherein the processor module is operable to synchronize with a second tag transceiver and determine the amount of radio frequency activity during a fixed passive period of the second tag transceiver.
Claim 4
Dependent Claim
44 words
The tag transceiver of claim 2, wherein: the fixed passive period of the second tag transceiver follows a fixed number of transmissions from the second tag transceiver; and the processor module synchronizes with the second tag transceiver by detecting the fixed number of transmissions.
Claim 5
Dependent Claim
66 words
The tag transceiver of claim 1, wherein: the period of time is a plurality of cycles; the amount of radio frequency traffic relates to a number of the cycles during which the processor module detects radio frequency activity; and the processor module initiates transmission of the signal if the number of cycles during which the processor module detects radio frequency activity is below a threshold value.
Claim 6
Dependent Claim
38 words
The tag transceiver of claim 1, wherein the processor module initiates transmission of the signal by generating a plurality of time slots and determining a specific time for transmitting the signal according to a randomized time slot selection.
Claim 7
Dependent Claim
26 words
The tag transceiver of claim 1, wherein the processor module activates from a stand-by state in response to receiving an activation signal at the receiver module.
Claim 8
Independent Claim
58 words
A method for transmitting data from a tag transceiver, the method comprising: listening for radio frequency activity; determining an amount of radio frequency activity during a period of time based on detected radio frequency activity during a plurality of sub-periods of the period; and initiating transmission of a response signal based on the amount of radio frequency activity.
Claim 9
Independent Claim
58 words
A method for transmitting data from a tag transceiver, the method comprising: listening for radio frequency activity; determining an amount of radio frequency activity during a period of time based on detected radio frequency activity during a plurality of sub-periods of the period; and initiating transmission of a response signal based on the amount of radio frequency activity.
Claim 10
Dependent Claim
34 words
The method of claim 7, further comprising: synchronizing the tag transceiver with a second tag transceiver; and determining the amount of radio frequency activity during a fixed passive period of the second tag transceiver.
Claim 11
Dependent Claim
43 words
The method of claim 8, wherein: the fixed passive period of the second tag transceiver follows a fixed number of transmissions from the second tag transceiver; and the tag transceiver synchronizes with the second tag transceiver by detecting the fixed number of transmissions.
Claim 12
Dependent Claim
66 words
The method of claim 7, wherein: the period of time is a plurality of cycles; the amount of radio frequency traffic relates to a number of the cycles during which the tag transceiver detects radio frequency activity; and the tag transceiver initiates transmission of the response signal if the number of cycles during which the tag transceiver detects radio frequency activity is below a threshold value.
Claim 13
Dependent Claim
35 words
The method of claim 7, wherein initiating transmission of the response signal comprises generating a plurality of time slots and determining a specific time for transmitting the signal according to a randomized time slot selection.
Claim 14
Dependent Claim
32 words
The method of claim 7, further comprising: receiving an activation signal from a reader transceiver; and changing from a stand-by state to an active state in response to receiving the activation signal.
Claim 15
Dependent Claim
80 words
A data transmission system, comprising: a reader transceiver operable to transmit a request signal; and a tag transceiver operable to receive the request signal and to transmit a response signal, wherein the tag transceiver listens for radio frequency activity, determines an amount of radio frequency activity during a period of time based on detected radio frequency activity during a plurality of sub-periods of the period, and initiates transmission of the response signal based on the amount of radio frequency activity.
Claim 16
Dependent Claim
80 words
A data transmission system, comprising: a reader transceiver operable to transmit a request signal; and a tag transceiver operable to receive the request signal and to transmit a response signal, wherein the tag transceiver listens for radio frequency activity, determines an amount of radio frequency activity during a period of time based on detected radio frequency activity during a plurality of sub-periods of the period, and initiates transmission of the response signal based on the amount of radio frequency activity.
Claim 17
Dependent Claim
37 words
The system of claim 13, wherein the tag transceiver is operable to synchronize with a second tag transceiver and to determine the amount of radio frequency activity during a fixed passive period of the second tag transceiver.
Claim 18
Dependent Claim
43 words
The system of claim 14, wherein: the fixed passive period of the second tag transceiver follows a fixed number of transmissions from the second tag transceiver; and the tag transceiver synchronizes with the second tag transceiver by detecting the fixed number of transmissions.
Claim 19
Dependent Claim
65 words
The system of claim 13, wherein: the period of time is a plurality of cycles; the amount of radio frequency traffic relates to a number of the cycles during which the tag transceiver detects radio frequency activity; and the tag transceiver initiates transmission of the signal if the number of cycles during which the tag transceiver detects radio frequency activity is below a threshold value.
Claim 20
Dependent Claim
38 words
The system of claim 13, wherein the tag transceiver initiates transmission of the response signal by generating a plurality of time slots and determining a specific time for transmitting the signal according to a randomized time slot selection.
Claim 21
Dependent Claim
33 words
The system of claim 13, wherein: the reader transceiver transmits an activation signal; and the tag transceiver changes from a stand-by state to an active state in response to receiving the activation signal.
Claim 22
Dependent Claim
42 words
The system of claim 13, wherein: the reader transceiver transmits an acknowledgment signal in response to receiving the response signal from the tag transceiver; and the tag transceiver re-transmits the response signal if the tag transceiver does not receive the acknowledgment signal.
Claim 23
Dependent Claim
44 words
The system of claim 13, wherein: the response signal includes a reader identification associated with the reader transceiver; and a second reader transceiver is operable to receive the response signal and communicate the response signal to the reader transceiver based on the reader identification.
Claim 24
Dependent Claim
67 words
The system of claim 13, wherein: the request signal includes a tag identification associated with the tag transceiver; the tag transceiver is operable to receive a portion of the request signal including the tag identification and to transmit an error signal indicating a failure to receive the complete request signal; and the reader transceiver is operable to receive the error signal and to re-transmit the request signal.
Claim 25
Independent Claim
76 words
A method for transmitting data from a tag transceiver, comprising; listening for transmission activity at a radio frequency, the transmission activity including transmissions from other tag transceivers; determining an amount of transmission activity at the radio frequency during a period of time; generating a number of time slots based on the amount of transmission activity; randomly selecting one of the time slots as a transmission time slot; and transmitting a signal during the transmission time slot.
Claim 26
Independent Claim
76 words
A method for transmitting data from a tag transceiver, comprising; listening for transmission activity at a radio frequency, the transmission activity including transmissions from other tag transceivers; determining an amount of transmission activity at the radio frequency during a period of time; generating a number of time slots based on the amount of transmission activity; randomly selecting one of the time slots as a transmission time slot; and transmitting a signal during the transmission time slot.
Claim 27
Dependent Claim
19 words
The method of claim 22, wherein the number of time slots is proportional to the amount of transmission activity.
Claim 28
Dependent Claim
19 words
The method of claim 22, wherein the transmission time slot is randomly selected from the plurality of time slots.
Claim 29
Dependent Claim
29 words
The method of claim 22, further comprising immediately initiating transmission of the signal in response to detecting no transmission activity at the radio frequency during the period of time.
Claim 30
Dependent Claim
34 words
The method of claim 22, further comprising: synchronizing the tag transceiver with a second tag transceiver; and determining the amount of transmission activity during a fixed passive transmission period of the second tag transceiver.
Claim 31
Dependent Claim
44 words
The method of claim 26, wherein: the fixed passive transmission period of the second tag transceiver follows a fixed number of transmissions from the second tag transceiver; and a tag transceiver synchronizes with the second tag transceiver by detecting the fixed number of transmissions.
Claim 32
Dependent Claim
30 words
The method of claim 27, wherein the period of time is a plurality of transmission cycles of the second tag transceiver and each transmission cycle includes the fixed passive period.
References Cited (Backward Citations)
US4303910A
Cited
US4471345A
Cited
US4528663A
Cited
US4862160A
Cited
EP0161779A1
Cited
US4691202A
Cited
EP0245555A1
Cited
US4955038A
Cited
US5668803A
Cited
US5153878A
Cited
WO1991017515A1
Cited
US5686902A
Cited
EP0467036A2
Cited
US5640151A
Cited
US5272476A
Cited
US5175729A
Cited
US5305008A
Cited
WO1993004537A1
Cited
US5220557A
Cited
US5266925A
Cited
EP0565046A2
Cited
US5425032A
Cited
US5371899A
Cited
US5227803A
Cited
US5351052A
Cited
US5453747A
Cited
US5539394A
Cited
US5450087A
Cited
US5448242A
Cited
US5621412A
Cited
US5525994A
Cited
US5488376A
Cited
US5471212A
Cited
US5754541A
Cited
US5525992A
Cited
US5721733A
Cited
US5737330A
Cited
US5745037A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-03-07 | 2003-09-06 | 2004-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-03-07 | 2007-09-06 | 2008-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-03-07 | 2011-09-06 | 2012-03-07 | $7700.00 | Window Closed / Lapsed |