Apparatuses, systems, and methods for communicating using MIMO and spread spectrum coding in backscatter of ambient signals
First Claim
1. An apparatus comprising:
- a first antenna configured to receive a first version of a backscattered radio frequency (RF) signal, wherein the first version of the backscattered RF signal includes a first phase;
a second antenna configured to receive a second version of the backscattered RF signal, wherein the second version of the backscattered RF signal includes a second phase different than the first phase;
a receiver coupled to the first antenna and the second antenna, wherein the receiver comprises;
a first envelope detector circuit configured to filter out transitions of the first version of the backscattered RF signal received at the first antenna to provide a first signal envelope;
wherein the receiver is configured to utilize analog circuitry to perform demodulation of the backscattered RF signal to provide output bits using at least one of;
(1) multiple input, multiple output (MIMO) multiplexing demodulation, or(2) spread spectrum code demodulation, wherein the spread spectrum code demodulation is based on demodulating the backscattered RF signal into a pseudorandom string of bits; and
power harvest circuitry configured to harvest power from the RF signal to power the demodulation.
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Accused Products
Abstract
Apparatuses, systems, ambient RF backscatter transceivers, and methods for communicating using MIMO and spread spectrum coding of backscattered ambient RF signals are described. An example system may include an ambient RF backscatter transceiver that include an antenna configured to receive a backscattered ambient radio frequency (RF) signal, and a receiver coupled to the antenna. The receiver may be configured to demodulate the backscattered ambient RF signal using one of multiple input, multiple output multiplexing demodulation or spread spectrum code demodulation to retrieve the first data. The backscattered ambient RF signal may be generated by backscattering an ambient RF signal at a first frequency. The ambient RF signal may be configured to provide other data at a second frequency.
119 Citations
13 Claims
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1. An apparatus comprising:
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a first antenna configured to receive a first version of a backscattered radio frequency (RF) signal, wherein the first version of the backscattered RF signal includes a first phase; a second antenna configured to receive a second version of the backscattered RF signal, wherein the second version of the backscattered RF signal includes a second phase different than the first phase; a receiver coupled to the first antenna and the second antenna, wherein the receiver comprises; a first envelope detector circuit configured to filter out transitions of the first version of the backscattered RF signal received at the first antenna to provide a first signal envelope; wherein the receiver is configured to utilize analog circuitry to perform demodulation of the backscattered RF signal to provide output bits using at least one of; (1) multiple input, multiple output (MIMO) multiplexing demodulation, or (2) spread spectrum code demodulation, wherein the spread spectrum code demodulation is based on demodulating the backscattered RF signal into a pseudorandom string of bits; and power harvest circuitry configured to harvest power from the RF signal to power the demodulation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus comprising:
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an antenna configured to receive a backscattered radio frequency (RF) signal, the backscattered RF signal comprising data encoded using spread spectrum coding; wherein a string of the backscattered RF signal having a first value is alternative ones and zeroes, and another string of the backscattered RF signal having a second value is all zeroes; and a receiver coupled to the antenna, wherein the receiver is configured to demodulate the backscattered RF signal using a spread spectrum code demodulation circuit to provide output bits, wherein the spread spectrum code demodulation circuit comprises analog circuitry configured to discriminate between codes of the spread spectrum coding. - View Dependent Claims (11, 12)
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13. An apparatus comprising:
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an antenna configured to receive a backscattered radio frequency (RF) signal, the backscattered RF signal comprising data encoded using spread spectrum coding; and a receiver coupled to the antenna, wherein the receiver is configured to demodulate the backscattered RF signal using a spread spectrum code demodulation circuit to provide output bits, wherein the spread spectrum code demodulation circuit comprises analog circuitry configured to discriminate between codes of the spread spectrum coding;
wherein the spread spectrum code demodulation circuit further comprises a summation circuit configured to add a magnitude of an in-phase component and a magnitude of a quadrature-phase component to produce a sum signal, wherein the summation circuit comprises;an amplifier configured to provide the sum signal at an output based on the magnitude of the in-phase component and the magnitude of the quadrature-phase component received at a first input, wherein a second input of the amplifier is coupled to a reference node; a first resistor configured to provide the magnitude of the in-phase signal to the first input of the amplifier; and a second resistor configured to provide the magnitude of the quadrature-phase signal to the first input of the amplifier.
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Specification