University of Washington

Bryce Kellogg

Joshua R Smith

Shyamnath Gollakota

Vamsi Talla

David Wetherall

Aaron N Parks

Saman Naderiparizi

Vikram Subramaniam Iyer

Ali Najafi

Mehrdad Hessar

Ben Ransford

Examples described herein include devices and systems utilizing backscatter communication to generate transmissions in accordance with wireless communication protocols. Examples are described including single sideband operation, generation of a carrier wave using Bluetooth, downlink communication to a backscatter device, and combinations thereof.

Backscatter devices including examples of single sideband operation

Examples described herein include devices and systems utilizing backscatter communication to directly generate transmissions in accordance with wireless communication protocols that can be decoded existing devices. Examples include devices that generate 802.11b transmissions using backscatter communication. Examples of network stacks are described which may facilitate backscatter devices to coexist with other devices (e.g. in the ISM band), without incurring, or reducing a need for, the power consumption or carrier sense and medium access control operations.

Backscatter devices and network systems incorporating backscatter devices

Examples of backscatter systems, device, and techniques are described herein. Example backscatter devices may utilize CSS modulation to provide backscatter signals including CSS signals (e.g., LoRa packets). Utilizing CSS modulation may advantageously allow for backscatter communication over wide areas. Examples of backscatter devices described herein may toggle the impedance of the backscatter device between multiple (e.g., eight) impedances to reduce and/or eliminate higher order harmonic components in the backscatter signal (e.g., third and fifth harmonic components).

Backscatter systems, devices, and techniques utilizing CSS modulation and/or higher order harmonic cancellation

Examples described herein include backscatter devices which may transmit orthogonal frequency division multiplexing (OFDM) signals. Techniques for complex analog backscatter are described. Examples of impedance circuitry are described which may be used to provide real and imaginary components of impedance in accordance with inphase and quadrature bits.

Backscatter devices and systems providing backscattered signals including OFDM packets

Examples described herein include wireless transmitters configured for power transmission. Example wireless transmitters may insert power packets into wireless communications such that power harvesting circuitry may harvest sufficiently continuous power from the wireless communication signals. Example power harvesting circuitry is configured to harvest power across multiple wireless communication channels. Example chargers are described which may harvest power from wireless communication signals (e.g. Wi-Fi signals).

Power transmission using wireless communication signals

Example devices described herein include endpoint devices which may communicate with an access point device by modulating a channel associated with the wireless communication to encode transmit data. The channel modulation may be performed by utilizing a switch to control an impedance of an antenna at the endpoint device to either reflect or absorb wireless network communication signals received by the endpoint device. The access point device may extract the transmit data by decoding changes in the channel caused, at least in part, by the modulation. Access point devices may transmit a pattern of packets&#x2014;the presence or absence of which may correspond with transmit data. Endpoint devices may decode this data by using an energy detector to differentiate between the presence or absence of a packet.

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Seattle, WA, United States of America

Bryce Kellogg