A Low-Power Backscatter Modulation System Communicating Across Tens of Meters With Standards-Compliant Wi-Fi Transceivers

This article presents the first integrated circuit designed to enable low-power backscatter communication with commodity Wi-Fi transceivers. The developed chip operates by receiving a series of packets generated from a Wi-Fi access point (AP), which feeds into a low-power energy-detecting wake-up receiver that determines when backscatter communication should commence. Then, the Wi-Fi AP sends an additional packet that is intended to be backscatter modulated. To accomplish this, the antenna receiving the incident Wi-Fi packet is terminated by a dynamically varying collection of complex impedances via a crystal-stabilized multi-phase local oscillator driven by a single-sideband (SSB) mixer, which ultimately performs SSB quadrature phase shift-keying (QPSK) modulation with frequency-translation to a separate Wi-Fi channel for reception by a second Wi-Fi AP. Implemented in 65-nm CMOS, the downlink wake-up receiver consumes 2.8 $\mu \text{W}$ and achieves a sensitivity of −42.5 dBm, which is good enough for >30 m wake-up range, while the backscattering uplink consumes 28 $\mu \text{W}$ and achieves 17 dB of image rejection. Wireless tests reveal a range of 21 m when the developed IC is placed symmetrically between Wi-Fi access points (APs), and a range of >90 m when the developed IC is placed within 1 m of the transmitting Wi-Fi AP.

[1]  Gabriel M. Rebeiz,et al.  A Near-Zero-Power Wake-Up Receiver Achieving −69-dBm Sensitivity , 2018, IEEE Journal of Solid-State Circuits.

[2]  Patrick P. Mercier,et al.  28.2 A 220μW -85dBm Sensitivity BLE-Compliant Wake-up Receiver Achieving -60dB SIR via Single-Die Multi- Channel FBAR-Based Filtering and a 4-Dimentional Wake-Up Signature , 2019, 2019 IEEE International Solid- State Circuits Conference - (ISSCC).

[3]  J. Teizer,et al.  Quadrature Amplitude Modulated Backscatter in Passive and Semipassive UHF RFID Systems , 2012, IEEE Transactions on Microwave Theory and Techniques.

[4]  Behzad Razavi,et al.  A 900-MHz/1.8-GHz CMOS transmitter for dual-band applications , 1999 .

[5]  Anantha P. Chandrakasan,et al.  Ultra-Low-Power Short-Range Radios , 2015 .

[6]  Noboru Ishihara,et al.  RF-Powered Transceiver With an Energy- and Spectral-Efficient IF-Based Quadrature Backscattering Transmitter , 2015, IEEE Journal of Solid-State Circuits.

[7]  Joshua R. Smith,et al.  Wi-fi backscatter , 2014, SIGCOMM 2015.

[8]  Siyuan Yu,et al.  A CMOS Distributed Sensor System for High-Density Wireless Neural Implants for Brain-Machine Interfaces , 2018, ESSCIRC 2018 - IEEE 44th European Solid State Circuits Conference (ESSCIRC).

[9]  Patrick P. Mercier,et al.  20.1 A 28µW IoT Tag That Can Communicate with Commodity WiFi Transceivers via a Single-Side-Band QPSK Backscatter Communication Technique , 2020, 2020 IEEE International Solid- State Circuits Conference - (ISSCC).

[10]  Ron Oliver,et al.  Design of ultra-low-cost UHF RFID tags for supply chain applications , 2004, IEEE Communications Magazine.

[11]  Martin Fischer,et al.  Fully integrated passive UHF RFID transponder IC with 16.7-μW minimum RF input power , 2003, IEEE J. Solid State Circuits.

[12]  Patrick P. Mercier,et al.  A 4.4μW −92/−90.3dBm Sensitivity Dual-Mode BLE/Wi-Fi Wake-up Receiver , 2020, 2020 IEEE Symposium on VLSI Circuits.

[13]  Wooi Gan Yeoh,et al.  A CMOS 2.45-GHz radio frequency identification tag IC with read/write memory , 2005, 2005 IEEE Radio Frequency integrated Circuits (RFIC) Symposium - Digest of Papers.

[14]  M. Tierney,et al.  A 200µm × 200µm × 100µm, 63nW, 2.4GHz injectable fully-monolithic wireless bio-sensing system , 2017, 2017 IEEE Radio Frequency Integrated Circuits Symposium (RFIC).

[15]  Sachin Katti,et al.  HitchHike: Practical Backscatter Using Commodity WiFi , 2016, SenSys.

[16]  Gabriel M. Rebeiz,et al.  A 400 MHz 4.5 nW −63.8 dBm sensitivity wake-up receiver employing an active pseudo-balun envelope detector , 2017, ESSCIRC 2017 - 43rd IEEE European Solid State Circuits Conference.

[17]  Joshua R. Smith,et al.  PASSIVE WI-FI: Bringing Low Power to Wi-Fi Transmissions , 2016, GETMBL.

[19]  Steve Lazar,et al.  A Passive UHF RFID Transponder for EPC Gen 2 with -14dBm Sensitivity in 0.13μm CMOS , 2007, 2007 IEEE International Solid-State Circuits Conference. Digest of Technical Papers.

[20]  David D. Wentzloff,et al.  26.8 A 236nW −56.5dBm-sensitivity bluetooth low-energy wakeup receiver with energy harvesting in 65nm CMOS , 2016, 2016 IEEE International Solid-State Circuits Conference (ISSCC).

[21]  Sachin Katti,et al.  Full duplex radios , 2013, SIGCOMM.