Frequency hopping spread spectrum scheme for RFID reader
First Claim
1. A radio frequency identification (RFID) system, comprising:
- an RFID base station adapted to communicate with at least one RFID transponder;
said RFID base station comprising;
a transmitter adapted to transmit radio frequency (RF) signals to said at least one RFID transponder;
a receiver adapted to receive RF signals backscattered from said at least one RFID transponder; and
a processor electrically connected to said transmitter and said receiver, and adapted to;
determine the amount of time available on a first carrier frequency;
determine the amount of time it would take to perform a particular transaction, wherein said particular transaction comprises a worst-case transaction, such that said processor is adapted to determine the amount of time it would take to perform the longest possible transaction; and
change to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to perform said particular transaction.
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Accused Products
Abstract
A system and method is provided for implementing forced frequency “hops” if the time it takes to perform a particular transaction is greater than the time available on a particular carrier frequency. In one embodiment of the present invention, a radio frequency identification (RFID) base station processor (in conjunction with program information stored in a base station memory) is adapted to (i) determine the amount of time available on a particular carrier frequency (e.g., pursuant to Federal Communications Commission (FCC) regulations, European Telecommunications Standardization Institute (ETSI) regulations, etc.), (ii) determine the amount of time it would take to perform a particular transaction, and (iii) force the base station to “hop” to another carrier frequency if the transaction time is longer than the available time. In one embodiment of the present invention, the time it would take to perform a particular transaction is the time it would take to perform the next transaction. In another embodiment of the present invention, the time it would take to perform a particular transaction is the time it would take to perform the longest (or “worst-case”) transaction. In alternate embodiments of the present invention, a transaction is defined as the transmission of information (e.g., data, commands, etc.) or both the transmission of information and the reception of related information.
22 Citations
21 Claims
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1. A radio frequency identification (RFID) system, comprising:
an RFID base station adapted to communicate with at least one RFID transponder;
said RFID base station comprising;a transmitter adapted to transmit radio frequency (RF) signals to said at least one RFID transponder; a receiver adapted to receive RF signals backscattered from said at least one RFID transponder; and a processor electrically connected to said transmitter and said receiver, and adapted to; determine the amount of time available on a first carrier frequency; determine the amount of time it would take to perform a particular transaction, wherein said particular transaction comprises a worst-case transaction, such that said processor is adapted to determine the amount of time it would take to perform the longest possible transaction; and change to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to perform said particular transaction.
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2. A radio frequency identification (RFID) system, comprising:
an RFID base station adapted to communicate with at least one RFID transponder;
said RFID base station comprising;a transmitter adapted to transmit radio frequency (RF) signals to said at least one RFID transponder; a receiver adapted to receive RF signals backscattered from said at least one RFID transponder; and a processor electrically connected to said transmitter and said receiver, and adapted to; determine the amount of time available on a first carrier frequency; determine the amount of time it would take to perform a particular transaction, wherein said particular transaction comprises a worst-case transaction, such that said processor is adapted to determine the amount of time it would take to perform the longest possible transaction with said at least one RFID transponder; and change to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to perform said particular transaction.
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3. A radio frequency identification (RFID) system, comprising:
an RFID base station adapted to communicate with at least one RFID transponder in accordance with a predetermined hopping sequence defined by a frequency hopping algorithm;
said RFID base station comprising;a transmitter adapted to transmit radio frequency (RF) signals to said at least one RFID transponder; a receiver adapted to receive RF signals backscattered from said at least one RFID transponder; and a processor electrically connected to said transmitter and said receiver, and adapted to; determine the amount of time available on a first carrier frequency of the hopping sequence; determine the amount of time it would take to perform a particular transaction, wherein said particular transaction is a transmission of a particular RF signal, such that said processor is adapted to determine the amount of time it would take to transmit said particular RF signal; and change to a second carrier frequency of the hopping sequence before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to perform said particular transaction. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A radio frequency identification (RFID) system, comprising:
an RFID base station adapted to communicate with at least one RFID transponder;
said RFID base station comprising;a transmitter adapted to transmit radio frequency (RF) signals to said at least one RFID transponder; a receiver adapted to receive RF signals backscattered from said at least one RFID transponder; and a processor electrically connected to said transmitter and said receiver, and adapted to; determine the amount of time available on a first carrier frequency; determine the amount of time it would take to perform a particular transaction, wherein said particular transaction is both a transmission of a particular RF signal and an expected reception of a particular RF signal in response thereto, such that said processor is adapted to determine the amount of time it would take to transmit said particular RF signal and the expected amount of time it would take to receive said particular RF signal in response thereto; and change to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to perform said particular transaction.
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10. A method for improving transmission rates in a radio-frequency-identification (RFID) base station, comprising:
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performing a first transaction with at least one RFID transponder over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to perform a worst-case transaction, said worst-case transaction being the longest transaction that can be performed by said RFID base station; forcing said RFID base station to hop to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to perform said worst-case transaction.
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11. A method for improving transmission rates in a radio-frequency-identification (RFID) base station, comprising:
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performing a first transaction with at least one RFID transponder over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to perform a worst-case transaction, said worst-case transaction being the longest transaction that can be performed by said RFID base station and with said at least one RFID transponder; forcing said RFID base station to hop to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to perform said worst-case transaction.
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12. A method for improving transmission rates in a radio-frequency-identification (RFID) base station, comprising:
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performing a first transaction with at least one RFID transponder over a first carrier frequency in a predetermined hopping sequence; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to transmit a particular radio frequency (RF) signal; forcing said RFID base station to hop to a second carrier frequency in the predetermined hopping sequence before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to transmit said particular RF signal. - View Dependent Claims (13)
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14. A method for improving transmission rates in a radio-frequency-identification (RFID) base station, comprising:
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performing a first transaction with at least one RFID transponder over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to transmit a particular radio frequency (RF) signal and an amount of time that it might take to receive a responsive RF signal from said at least one RFID transponder; forcing said RFID base station to hop to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to transmit said particular RF signal and said amount of time it might take to receive said responsive RF signal from said at least one RFID transponder.
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15. A method for improving transmission rates in a radio-frequency-identification (RFID) base station, comprising:
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performing a first transaction with at least one RFID transponder over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to transmit a particular radio frequency (RF) signal; forcing said RFID base station to hop to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to transmit said particular RF signal; wherein said step of determining the amount of time available on said first carrier frequency further comprises comparing the amount of time that the RFID base station has continuously been on said first carrier frequency to an amount of time permitted by the Federal Communications Commission (FCC).
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16. A method for improving transmission rates in a radio-frequency-identification (RFID) base station, comprising:
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performing a first transaction with at least one RFID transponder over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to transmit a particular radio frequency (RF) signal; forcing said RFID base station to hop to a second carrier frequency before said amount of time available on said first carrier frequency expires when said amount of time on said first carrier frequency is less than said amount of time it would take to transmit said particular RF signal; wherein said step of determining the amount of time it would take to transmit a particular RF signal is performed prior to said step of determining the amount of time available on said first carrier frequency.
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17. A frequency-hopping-spread-spectrum (FHSS) method for use in a radio-frequency-identification (RFID) device, comprising:
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transmitting a first radio frequency (RF) signal over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to transmit a particular RF signal; transmitting a second RF signal over said first carrier frequency when said amount of time available on said first carrier frequency is greater than said amount of time it would take to transmit said particular RF signal; and transmitting a second RF signal over a second carrier frequency when said amount of time available on said first carrier frequency is less than said amount of time it would take to transmit said particular RF signal. - View Dependent Claims (18, 19)
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20. A frequency-hopping-spread-spectrum (FHSS) method for use in a radio-frequency-identification (RFID) device, comprising:
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transmitting a first radio frequency (RF) signal over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to transmit a particular RF signal; transmitting a second RF signal over said first carrier frequency when said amount of time available on said first carrier frequency is greater than said amount of time it would take to transmit said particular RF signal; and transmitting a second RF signal over a second carrier frequency when said amount of time available on said first carrier frequency is less than said amount of time it would take to transmit said particular RF signal; wherein said step of determining the amount of time it would take to transmit a particular RF signal further comprises determining the amount of time it would take to transmit an RF signal having the longest transmission time of any RF signal that might be transmitted by said RFID device.
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21. A frequency-hopping-spread-spectrum (FHSS) method for use in a radio-frequency-identification (RFID) device, comprising:
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transmitting a first radio frequency (RF) signal over a first carrier frequency; determining the amount of time available on said first carrier frequency; determining the amount of time it would take to transmit a particular RF signal; transmitting a second RF signal over said first carrier frequency when said amount of time available on said first carrier frequency is greater than said amount of time it would take to transmit said particular RF signal; transmitting a second RF signal over a second carrier frequency when said amount of time available on said first carrier frequency is less than said amount of time it would take to transmit said particular RF signal; and determining the amount of time it would take to receive a modulated RF signal; wherein said steps of transmitting a second RF signal further comprise; transmitting a second RF signal over said first carrier frequency when said amount of time available on said first carrier frequency is greater than the product of said amount of time it would take to transmit said particular RF signal and said amount of time it would take to receive said modulated RF signal; and transmitting a second RF signal over said second carrier frequency when said amount of time available on said first carrier frequency is less than the product of said amount of time it would take to transmit said particular RF signal and said amount of time it would take to receive said modulated RF signal; and wherein said steps of determining amounts of time it would take to transmit a particular RF signal and receive a modulated RF signal further comprise; determining the amount of time it would take to transmit an RF signal having the longest transmission time of any RF signal that might be transmitted by said RFID device; and determining the amount of time it might take to receive a modulated RF signal in response to transmitting said RF signal having the longest transmission time.
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Specification