Battery-Free Cellphone

We present the first battery-free cellphone design that consumes only a few micro-watts of power. Our design can sense speech, actuate the earphones, and switch between uplink and downlink communications, all in real time. Our system optimizes transmission and reception of speech while simultaneously harvesting power which enables the battery-free cellphone to operate continuously. The battery-free device prototype is built using commercial-off-the-shelf components on a printed circuit board. It can operate on power that is harvested from RF signals transmitted by a basestation 31 feet (9.4 m) away. Further, using power harvested from ambient light with tiny photodiodes, we show that our device can communicate with a basestation that is 50 feet (15.2 m) away. Finally, we perform the first Skype call using a battery-free phone over a cellular network, via our custom bridged basestation. This we believe is a major leap in the capability of battery-free devices and a step towards a fully functional battery-free cellphone.

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

[2]  Joshua R. Smith,et al.  Powering the next billion devices with wi-fi , 2015, CoNEXT.

[3]  Bo Gao,et al.  A System-on-Chip EPC Gen-2 Passive UHF RFID Tag With Embedded Temperature Sensor , 2010, IEEE Journal of Solid-State Circuits.

[4]  Mohammad Rostami,et al.  Enabling Practical Backscatter Communication for On-body Sensors , 2016, SIGCOMM.

[5]  Pan Hu,et al.  EkhoNet: high speed ultra low-power backscatter for next generation sensors , 2014, MobiCom.

[6]  D. P. C. Thackeray.  When tubes beat crystals: early radio detectors , 1983, IEEE Spectrum.

[7]  Yong-xin Guo,et al.  A Dual-Band Rectenna Using Broadband Yagi Antenna Array for Ambient RF Power Harvesting , 2013, IEEE Antennas and Wireless Propagation Letters.

[8]  Shyamnath Gollakota,et al.  Bringing Gesture Recognition to All Devices , 2014, NSDI.

[9]  Yi Hu,et al.  Evaluation of Objective Quality Measures for Speech Enhancement , 2008, IEEE Transactions on Audio, Speech, and Language Processing.

[10]  Matthew S. Reynolds,et al.  Every smart phone is a backscatter reader: Modulated backscatter compatibility with Bluetooth 4.0 Low Energy (BLE) devices , 2015, 2015 IEEE International Conference on RFID (RFID).

[11]  Mani B. Srivastava,et al.  Design considerations for solar energy harvesting wireless embedded systems , 2005, IPSN 2005. Fourth International Symposium on Information Processing in Sensor Networks, 2005..

[12]  Deepak Ganesan,et al.  Enabling Bit-by-Bit Backscatter Communication in Severe Energy Harvesting Environments , 2014, NSDI.

[13]  Pan Hu,et al.  EkhoNet: High-Speed Ultra Low-Power Backscatter for Next Generation Sensors , 2015, GETMBL.

[14]  Angli Liu,et al.  Turbocharging ambient backscatter communication , 2014, SIGCOMM.

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

[16]  J. R. Smith,et al.  Hybrid analog-digital backscatter: A new approach for battery-free sensing , 2013, 2013 IEEE International Conference on RFID (RFID).

[17]  Deepak Ganesan,et al.  BLINK: a high throughput link layer for backscatter communication , 2012, MobiSys '12.

[18]  Joshua R. Smith,et al.  Experimental results with two wireless power transfer systems , 2009, 2009 IEEE Radio and Wireless Symposium.

[19]  David Wetherall,et al.  Dewdrop: An Energy-Aware Runtime for Computational RFID , 2011, NSDI.

[20]  Pan Hu,et al.  Laissez-Faire: Fully Asymmetric Backscatter Communication , 2015, SIGCOMM.

[21]  Joshua R. Smith,et al.  Inter-Technology Backscatter: Towards Internet Connectivity for Implanted Devices , 2016, SIGCOMM.

[22]  P.V. Nikitin,et al.  Antennas and Propagation in UHF RFID Systems , 2008, 2008 IEEE International Conference on RFID.

[23]  Min Li,et al.  Collision recovery receiver for EPC Gen2 RFID systems , 2012, 2012 3rd IEEE International Conference on the Internet of Things.

[24]  Yorgos Palaskas,et al.  Wi-Fi RF energy harvesting for battery-free wearable radio platforms , 2015, 2015 IEEE International Conference on RFID (RFID).

[25]  Joshua R. Smith,et al.  Sifting through the airwaves: Efficient and scalable multiband RF harvesting , 2014, 2014 IEEE International Conference on RFID (IEEE RFID).

[26]  Joshua R. Smith,et al.  WISPCam: A battery-free RFID camera , 2015, 2015 IEEE International Conference on RFID (RFID).

[27]  David Wetherall,et al.  Ambient backscatter: wireless communication out of thin air , 2013, SIGCOMM.

[28]  Alanson P. Sample,et al.  Design of an RFID-Based Battery-Free Programmable Sensing Platform , 2008, IEEE Transactions on Instrumentation and Measurement.

[29]  Yi Zhao,et al.  A wireless sensing platform utilizing ambient RF energy , 2013, 2013 IEEE 13th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems.

[30]  David Wetherall,et al.  The Emergence of RF-Powered Computing , 2014, Computer.

[31]  R. Hansen.  Relationships between antennas as scatterers and as radiators , 1989, Proc. IEEE.

[32]  J.A.C. Theeuwes,et al.  Ambient RF Energy Scavenging: GSM and WLAN Power Density Measurements , 2008, 2008 38th European Microwave Conference.

[33]  Y. Kawahara,et al.  E-WEHP: A Batteryless Embedded Sensor-Platform Wirelessly Powered From Ambient Digital-TV Signals , 2013, IEEE Transactions on Microwave Theory and Techniques.

[34]  Joshua R. Smith,et al.  FM Backscatter: Enabling Connected Cities and Smart Fabrics , 2017, NSDI.

[35]  Derrick Wing Kwan Ng,et al.  Simultaneous wireless information and power transfer in modern communication systems , 2014, IEEE Communications Magazine.

[36]  Joseph A. Paradiso,et al.  Energy scavenging for mobile and wireless electronics , 2005, IEEE Pervasive Computing.