Hitchhike : Enabling Low Power IoT on WiFi networks


Backscatter communication


RF signal generation is expensive and takes a lot of power. Hitchhike tackles this problem by recycling the ambient RF signals to embed the data from an IoT device.


Codeword translation

Hitchhike enables co-existence of IoT devices along with the user traffic on a Wifi network. It uses a novel technique called “Codeword translation” to embed data onto an existing wifi packet.

Prototype hardware and applications

Hitchhike’s hardware prototype consumes ~30uW of power. At this level of power consumption makes, an AA battery can last upto 15 years. The large shelf life of the tag makes it ideal for vast deployment of sensors in agricultural fields for moisture and temperature monitoring.



Hierarchical Wake-up receiver


We have developed a novel hierarchical wake-up receiver for backscatter tags to synchronize with incident signals. Traditional backscatter tags suffer from loss of synchronization resulting in lot of bit errors and limit the tag placement close to the transmitter. Here we demonstrate a wake-up receiver to enable synchronization at the tag at a very low power and increase the tag’s working range.


Publications

SyncScatter: Enabling WiFi like synchronization and range for WiFi backscatter Communication [Slides]
Manideep Dunna, Miao Meng, Pohan Peter Wang, Chi Zhang, Patrick Mercier, Dinesh Bharadia
NSDI 2021

Improving the Range of WiFi Backscatter Via a Passive Retro-Reflective Single-Side-Band-Modulating MIMO Array and Non-Absorbing Termination [Slides]
Miao Meng, Manideep Dunna, Hans Yu, Shikhai Kuo, Pohan Peter Wang, Dinesh Bharadia, Patrick Mercier
ISSCC 2021

A Low-Power Backscatter Modulation System Communicating Across Tens of Meters With Standards-Compliant Wi-Fi Transceivers
Po-Han Peter Wang, Chi Zhang, Hongsen Yang, Manideep Dunna, Dinesh Bharadia, Patrick Mercier
JSSC 2020

FreeRider: Backscatter Communication Using Commodity Radios [Slides]
Pengyu Zhang, Colleen Josephson, Dinesh Bharadia, Sachin Katti
CoNEXT 2017

HitchHike: Practical Backscatter using Commodity WiFi [Talk]
Pengyu Zhang (Co-primary), Dinesh Bharadia (Co-primary), Kiran Joshi, Sachin Katti
SenSys 2016
Best Paper Award Nominee
Press cover: Stanford News, ACM TechNews, ECN, Science Blog, Pace Today, North Dallas Gazette, New Electronics, RFID Journal, NFC World, etc.