Apparatuses, systems, and methods for communicating using MIMO and spread spectrum coding in backscatter of ambient signals
First Claim
1. A method, comprising:
- receiving a backscattered radio frequency (RF) signal at a first antenna, the backscattered ambient RF signal encoded with first data at a first frequency, the RF signal modulated to provide second data at a second frequency;
demodulating the backscattered ambient RF signal using spread spectrum code demodulation based on a chip duration; and
retrieving the first data based on the demodulated backscattered ambient RF signal, wherein, while demodulating the backscattered RF signal using spread spectrum code demodulation, demodulating the ambient backscattered RF signal based on an in-phase and quadrature-phase correlation, wherein the backscattered RF signal is modulated at a chip rate and the chip duration.
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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.
122 Citations
20 Claims
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1. A method, comprising:
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receiving a backscattered radio frequency (RF) signal at a first antenna, the backscattered ambient RF signal encoded with first data at a first frequency, the RF signal modulated to provide second data at a second frequency; demodulating the backscattered ambient RF signal using spread spectrum code demodulation based on a chip duration; and retrieving the first data based on the demodulated backscattered ambient RF signal, wherein, while demodulating the backscattered RF signal using spread spectrum code demodulation, demodulating the ambient backscattered RF signal based on an in-phase and quadrature-phase correlation, wherein the backscattered RF signal is modulated at a chip rate and the chip duration. - View Dependent Claims (2, 3, 4, 5, 6)
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7. 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 code circuit configured to compute an average of I and Q values over a chip duration; 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 (8, 9, 10, 11, 12, 13, 14)
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15. A method comprising:
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receiving a backscattered radio frequency (RF) signal encoded with first data at a first frequency, the RE signal modulated to provide second data at a second frequency, and wherein the backscattered RF signal was modulated at a chip rate and a chip duration; computing, over the chip duration, an average of I and Q values of an envelope signal, the envelope signal based on the backscattered RF signal; demodulating the backscattered ambient RF signal based partly on the average of the I and Q values of the envelope signal; and retrieving the first data based on the demodulated backscattered ambient RF signal. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification