Low power radio frequency communication
First Claim
1. A communication system comprising:
- an access point coupled to provide access to a network;
a radio-frequency (RF) tag communicatively coupled to the access point, the RF tag comprisingan energy harvesting unit operable to convert incident RF energy to direct current (DC);
a storage unit operable to store recovered DC power;
a passive wakeup pattern detector operable to generate an interrupt in response to detecting a set of one or more subcarriers;
one or more sensors for sensing;
a communication mechanism; and
a microcontroller coupled to the energy harvesting and storage units, and the one or more sensors, the microcontroller operable to wake up from a sleep state in response to the interrupt and cause the communication mechanism to exchange data wirelessly with a device while powered by energy previously harvested and stored by the energy harvesting and storage unit;
an antenna;
a first impedance matching circuit directly connecting the antenna to the passive wakeup pattern detector;
a switch connected to the antenna;
a second impedance matching circuit, separate from the first impedance matching circuit, on an output of the switch; and
a demodulator coupled to the switch via the second impedance matching circuit.
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Accused Products
Abstract
A method, system and tag for low power radio frequency communication is described. In one embodiment, the RF tag comprises: an access point coupled to provide access to a network; an RF tag comprising an energy harvesting unit operable to convert incident RF energy to direct current (DC); a storage unit operable to store recovered DC power; a passive wakeup pattern detector operable to generate an interrupt in response to detecting a set of one or more subcarriers; one or more sensors for sensing; a communication mechanism; and a microcontroller coupled to the energy harvesting and storage units, the one or more sensors, and the backscatter communicator, the microcontroller operable to wake up from a sleep state in response to the interrupt and cause the communication mechanism to exchange data wirelessly with another while powered by energy previously harvested and stored by the energy harvesting and storage unit.
60 Citations
20 Claims
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1. A communication system comprising:
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an access point coupled to provide access to a network; a radio-frequency (RF) tag communicatively coupled to the access point, the RF tag comprising an energy harvesting unit operable to convert incident RF energy to direct current (DC); a storage unit operable to store recovered DC power; a passive wakeup pattern detector operable to generate an interrupt in response to detecting a set of one or more subcarriers; one or more sensors for sensing; a communication mechanism; and a microcontroller coupled to the energy harvesting and storage units, and the one or more sensors, the microcontroller operable to wake up from a sleep state in response to the interrupt and cause the communication mechanism to exchange data wirelessly with a device while powered by energy previously harvested and stored by the energy harvesting and storage unit; an antenna; a first impedance matching circuit directly connecting the antenna to the passive wakeup pattern detector; a switch connected to the antenna; a second impedance matching circuit, separate from the first impedance matching circuit, on an output of the switch; and a demodulator coupled to the switch via the second impedance matching circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for communicating information wirelessly between an access point and a radio frequency (RF) tag having a passive wakeup pattern detector directly connected to an antenna via a first impedance matching circuit, the method comprising:
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monitoring, by the RF tag, radio frequency (RF) communications with the RF tag while converting incident RF energy to direct current using an energy harvesting unit of the RF tag; sending, by the access point, a first RF communication to the RF tag; detecting one or more subcarriers in the RF communications using the passive wakeup pattern detector in the RF tag; generating an interrupt to a microcontroller in the RF tag in response to detecting the one or more subcarriers; waking up the microcontroller in response to the interrupt to cause a communication mechanism of the RF tag to exchange data wirelessly with a device, the RF tag powered by powered by energy previously harvested and stored by the energy harvesting and storage unit; demodulating, by a demodulator, the RF communications and providing the demodulated RF communications to the microcontroller when the RF tag is not harvesting energy and when a switch, which is coupled to the antenna and coupled to the demodulator via a second impedance matching circuit separate from the first impedance matching circuit, provides the RF communications to the demodulator from the antenna; and communicating information between the RF tag and the access point. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification