Radio-frequency identification (RFID) tag employing unique reception window and method therefor
First Claim
1. A wireless identification tag, comprising:
- a battery for powering internal circuits of said tag;
a transmitter for transmitting signals encoding at least an identifier of said tag;
a receiver for receiving system signals from an external system in communication with said tag, wherein said system signals include a tag address; and
a timer for activating said receiver for a predetermined period of time subsequent to said transmitter transmitting said signals, whereby said system signals are received by said tag during a predictable window subsequent to transmissions of said tag, and whereby power consumption from said battery is further conserved;
a storage for storing parameters of said tag, said parameters including one or more values corresponding to;
said predetermined period of time, a period of said transmitted signals, a start time of said transmitted signals and an amplitude of said transmitted signals, and wherein said transmitter produces said transmitted signals in conformity with said stored parameters, when the period of said transmitted signal is shortened.
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Accused Products
Abstract
A radio-frequency identification (RFID) tag employing a unique reception window and method for operating the tag system provides low-power operation for enhanced tag battery life, while providing addressable tags that can receive commands and data from the system, which can be a wireless local area network (WLAN) incorporating location finding for locating the tags. Interference with other tags and other transmitters is prevented by either using a sniffer circuit to determine that no network transmission is in progress, or by using a special non-interfering coding sequence. A receiver within the tag is operated for a predetermined period of time after a periodic transmission is made from the tag, and an address decoder determines if the tag is being addressed. The receiver can receive data and/or commands after being addressed and is shutdown if the window time elapses, the tag is not addressed, or at the completion of data/command transfer.
100 Citations
24 Claims
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1. A wireless identification tag, comprising:
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a battery for powering internal circuits of said tag; a transmitter for transmitting signals encoding at least an identifier of said tag; a receiver for receiving system signals from an external system in communication with said tag, wherein said system signals include a tag address; and a timer for activating said receiver for a predetermined period of time subsequent to said transmitter transmitting said signals, whereby said system signals are received by said tag during a predictable window subsequent to transmissions of said tag, and whereby power consumption from said battery is further conserved; a storage for storing parameters of said tag, said parameters including one or more values corresponding to;
said predetermined period of time, a period of said transmitted signals, a start time of said transmitted signals and an amplitude of said transmitted signals, and wherein said transmitter produces said transmitted signals in conformity with said stored parameters, when the period of said transmitted signal is shortened. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of operating a wireless identification tag, comprising:
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transmitting a signal from said identification tag at periodic intervals, said signal bearing an identifier of said wireless identification tag; and operating a receiver within said wireless identification tag for only a predetermined period of time subsequent to an end of said periodic intervals, whereby signals from external devices may be received while reducing battery energy use by said receiver; wherein said signal transmits one, or more stored parameter values corresponding to said predetermined period of time, a period of said signal, a start time of said signal and amplitude of said signal, whereby said external devices can determine said one or more stored parameter values. - View Dependent Claims (20, 21, 22)
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23. A wireless identification tag comprising:
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a battery for powering internal circuits of said tag; a transmitter for transmitting tag signals encoding at least an identifier of said wireless identification tag and one or more stored parameter values corresponding to a predetermined period of time, a period of said signal, a start time of said signal and amplitude of said signal; a timer for activating said transmitter on a periodic basis to transmit said signals and deactivating said transmitter subsequent to transmitting said signals, whereby power consumption from said battery is conserved when said timer deactivates said transmitter; means for receiving system signals bearing at least one of commands and data from an external system. - View Dependent Claims (24)
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Specification