Prof. Ambuj Varshney

About Me

I am an Assistant Professor at the National University of Singapore.

I am bootstrapping WEISER group, consisting of curiosity driven group of students, engineers and researchers interested in Wireless, Embedded systems, Intelligence, Sensing and Emerging Technologies in Real World (WEISER). We are systems researcher, and work commonly at intersection of areas of electronics, communication and computer science. We work on problems with a strong engineering component, and potential for real-world impact.

Contact Details

I am located at Computing 3(COM3). My address is: #02-25, Computing 3, School of Computing, 11 Research Link, Singapore 119391. Email: ambujv@nus.edu.sg, Phone: +65 - 86706948

For scheduling and other general queries, you may email my personal assistant: Joy

Biography

Ambuj Varshney, a Swedish citizen, is an Assistant Professor at the National University of Singapore. Previously, he was a postdoctoral scholar at the Department of EECS of the University of California, Berkeley. He was also a visiting researcher (three months) at the Royal Institute of Technology (KTH). He completed his doctoral studies at Uppsala University, Sweden. As a PhD student, he was also closely associated with Swedish Institute of Computer Sciences (SICS) (Now called RISE). And even before, he was a software engineer (firmware) at NXP Semiconductors.

Ambuj Varshney’s interests over the past decade have centered around embedded systems, wireless, and mobile computing. He has tackled the problem of energy asymmetry among components of embedded systems, which is a pressing problem hindering their widespread deployment. Varshney has designed novel low-power wireless transmitters that achieve hundreds of meters of range at tens of microwatts of power consumption, which is orders of magnitude lower than widely used commercial transmitters. His research has led to awards, accolades, and research grants, and his doctoral dissertation was awarded the 2019 ABB Research Award in Honour of Hubertus von Gruenberg (with an endowment of 300,000 USD hosted at the University of California, Berkeley). Several of Varshney’s students have also received significant honors and accolades, including winning the ACM Student Research Competition at ACM MobiCom 2017. Varshney has served as a jury member, program committee member, and in organizational roles for several important scientific events.

You can also read more about me here: (ABB Featured artice)(English)(Swedish)

Research Interest

Our vision is to seamlessly integrate digital and physical worlds, thus providing tools for exploring and better understanding our world and reality. In pursuit of our vision, we are focused on two directions: STICORS and BeyondRF.

STICORS: This research directions aims to develop a framework for general purpose, flexible form factor, and long-lasting computers. Unlike traditional sensor platforms, these computers will not just sense and transmit information. They will be able to sense the physical world, actuate the environment, interact with users, process, store, and infer information, and transmit wirelessly. Based on our previous systems, such as LoRea (ACM SENSYS 2017) and Judo (ACM MOBISYS 2022), these computers will be able to communicate over long distances.

BEYOND RF: We are developing alternative wireless communication methods for Internet of Things (IoT) devices. The increasing number of IoT devices has led to challenges with energy and spectrum usage. To address these challenges, our projects focus on using; 1) visible light (LiFi) for communication to avoid using the RF spectrum altogether (VLCS 2016) (VLCS 2017) (MOBICOM 2019) (MOBISYS 2020) 2) Tunnel diode and backscatter transmitters that use orders of magnitude less energy than commercial transmitters (MOBICOM 2019) (MOBICOM 2020) (MOBISYS 2022); Previously, we have also investigated, 3) Electronically steerable directional atennas in IoT devices for spectrum efficient communication and sensing (IPSN 2015) (SENSYS 2015)

Recent News

Get to know about some of my research (2019 ABB Research Award Video):

Teaching and Mentorship

Mentored the following students (formally):

  1. Li Kunjun (2023 -) (Ongoing) [Undergraduate researcher, National University of Singapore]
    • Project/Thesis Title: Non-Intrusive Monitoring of Robots and IoT Devices (Jointly with NCS-NUS Lab)
  2. Steven Antya Orvala Waskito (2023 -) (Ongoing) [Undergraduate researcher, National University of Singapore]
    • Project/Thesis Title: Non-Intrusive Monitoring of Robots and IoT Devices (Jointly with NCS-NUS Lab)
  3. Yusril Izza (2023 -) (Ongoing) [Masters program, National University of Singapore]
    • Project/Thesis Title: Data Storage on IoT Devices
  4. Goh Sheen An (2023 -) (Ongoing) [Masters program, National University of Singapore]
    • Project/Thesis Title: Integration of Embedded Wireless Microphones with Open AI Whisper System
  5. Lim Soon Lee (2023 -) (Ongoing) [Masters program, National University of Singapore]
    • Project/Thesis Title: Fabricating Sticker Form-Factor Sensors
  6. Qiao Yukai (2022 -) (Ongoing) [Masters program, National University of Singapore]
    • Project/Thesis Title: Collecting and Analyzing Data from Battery-free Internet of Things
  7. David Håkansson (2022, Bachelors program, Uppsala University)
  8. Andreas Soleiman (2016-2019) [Research Assistant and Bachelors+Masters Program] → MIT EECS PhD (withdrew to stay in industry) → Senior Data Scientist, H&M Group, Stockholm, Sweden
  9. Gustav Eriksson/Fredholm (2018)[Masters program] → Teamleader Intertek Semko, Stockholm
  10. Oliver Harms (2016-2017)[Master program] → Chalmers PhD, Sweden
  11. Sam Hylamia (2017-2018)[Masters program and Research Assistant] → Uppsala University PhD
  12. Elena di Lascio (2015-2016) [Masters program] → USI PhD (completed) → Novartis Institutes for BioMedical Research (NIBR), Switzerland
  13. Simon Olofsson (2015)[Research assistant] → Imperial College London PhD → Facebook/Meta, London, UK

Collaborated with the following students:

Academic Service

Served as a member of jury or other significant roles in the following events:

Part of jury for 2022 ABB Research Award in Honour of HvG. Other members were:

Involved in the organizational role of the following events:

Part of the technical program committee (TPC) of the following scientific conferences:

Involved in reviewing of articles for the following journals:

Publications

Publication numbers are for reference only and not for the purpose of bean counting.

Year 2023

  1. TunnelLiFi: Bringing LiFi to Commodity Devices
    Authors: Muhammad Sarmad Mir, Wenqing Yan, Prabal Dutta, Domenico Giustiniano, and Ambuj Varshney
    The Twenty-fourth International Workshop on Mobile Computing Systems and Applications (ACM HotMobile 2023)
    (To appear)

Year 2022

  1. POSTER: Enabling L3: Low Cost, Low Complexity and Low Power Radio Frequency Sensing using Tunnel Diodes
    Authors: Wenqing Yan, Ambuj Varshney
    The Twenty Eight Annual International Conference On Mobile Computing And Networking (ACM MobiCom 2022)

  2. Making Low-power and Long-range Wireless Backscatter Transmitters
    Author: Ambuj Varshney
    ACM GetMobile: Mobile Computing and Communications (Maker Edition) 2022
    (Featured in editorial by Landon Cox (Microsoft Research)) Read the editorial here

  3. Judo: Addressing the Energy Asymmetry of Wireless Embedded Systems through Tunnel Diode based Wireless Transmitters
    Authors: Ambuj Varshney, Wenqing Yan, Prabal Dutta
    The Twentieth ACM International Conference on Mobile Systems, Applications, and Services (ACM MobiSys 2022)
  4. PassiveLiFi: Rethinking LiFi for Low-Power and Long Range RF Backscatter
    Authors: Muhammad Sarmad, Borja Genoves, Ambuj Varshney, Domenico Giustiniano
    The Twenty Seventh Annual International Conference On Mobile Computing And Networking (ACM MobiCom 2021/2022)
    (Due to the pandemic, conference was held in 2022)

Year 2021

  1. Securing Battery-free Backscatter Tags through Fingerprinting
    Authors: Revathy Narayanan, Ambuj Varshney, et al.
    The Twentieth ACM Workshop on Hot Topics in Networks (ACM HotNets 2021)

  2. Radio frequency communication device for low power communication
    Ambuj Varshney (Only inventor)
    [PCT/Patent Application] [WO2021040594A1]

Year 2020

  1. TunnelEmitter:Tunnel Diode based Low-Power Carrier Emitters for Backscatter Tags
    Authors: Ambuj Varshney, Lorenzo Corneo
    The Twenty Sixth Annual International Conference On Mobile Computing And Networking (ACM MobiCom 2020)
  2. Two to Tango: Hybrid Light and Backscatter Networks for Next Billion Devices
    Authors: Ambuj Varshney, Ander Galiesto, Domenico Giustiniano
    Co-primary author that contributed equally to the work
    The Eighteenth ACM International Conference on Mobile Systems, Applications, and Services (ACM MobiSys 2020)

Year 2019

  1. TunnelScatter: Low Power Communication for Sensor Tags using Tunnel Diodes
    Authors: Ambuj Varshney, Andreas Soleiman, Thiemo Voigt
    The Twenty Fifth Annual International Conference On Mobile Computing And Networking (ACM MobiCom 2019)

Year 2018

  1. Connecting Battery-free IoT Tags Using LED Bulbs
    Authors: Domenico Giustiniano, Ambuj Varshney, Thiemo Voigt
    The Eighteenth ACM Workshop on Hot Topics in Networks (ACM HotNets 2019)

  2. Demonstration: Towards Battery-free Radio Tomographic Imaging
    Authors: Abdullah Hylamia, Ambuj Varshney, Andreas Soleiman, et al.
    The Eleventh ACM Conference on Security and Privacy in Wireless and Mobile Networks (ACM WiSec-2018)
    Best demonstration award

  3. Battery-free 802.15.4 Receiver
    Authors: Carlos Perez Penichet, Claro Noda, Ambuj Varshney, Thiemo Voigt
    The Seventeenth ACM/IEEE Conference on Information Processing in Sensor Networks.(ACM/IEEE IPSN 2018)

  4. Enabling Sustainable Networked Embedded Systems
    Ambuj Varshney, Doctoral dissertation
    Awarded the 2019 ABB Research Award in Honour of HvG (with grant of 300k USD)
    Press release from Uppsala University
    Press release from ABB

Year 2017

  1. LoRea: A Backscatter Architecture that Achieves a Long Communication Range
    Authors: Ambuj Varshney, Oliver Harms, Carlos Penichet, Christian Rohner , Frederik Hermans, Thiemo Voigt
    Fifteenth ACM Conference on Embedded Networked Sensor Systems (ACM SENSYS 2017)
    2019 ABB Research Award Winner

  2. Battery-free Visible Light Sensing
    Authors: Ambuj Varshney, Andreas Soleiman, Luca Mottola, Thiemo Voigt
    ACM VLCS (Co-located with ACM MobiCom) 2017
    Best Paper Award
    ACM Student Research Competition Winner (Graduate, MobiCom) (Mentored student)

  3. Towards wide-area backscatter networks
    Authors: Ambuj Varshney, Carlos Perez Penichet, Christian Rohner, Thiemo Voigt
    ACM HotWireless (Co-located with ACM MobiCom) 2017

Year 2016

  1. modBulb: A Modular Light Bulb for Visible Light Communication
    Authors: Kasun Hewage, Ambuj Varshney, Abdalah Hilamia, Thiemo Voigt
    ACM VLCS (Co-located with ACM MobiCom) 2016

  2. Augmenting IoT Networks with Backscatter-Enabled Passive Sensor Tags
    Authors: Carlos Perez Penichet, Frederik Hermans, Ambuj Varshney, Thiemo Voigt
    ACM HotWireless (Co-located with ACM MobiCom) 2016

Year 2015

  1. Directional Transmissions and Receptions for High-throughput Bulk Forwarding in Wireless Sensor Networks
    Authors: Ambuj Varshney, Luca Mottola, Mats Carlsson, Thiemo Voigt
    Thirteenth ACM Conference on Embedded Networked Sensor Systems (ACM SENSYS 2015)
  2. dRTI: Directional Radio Tomographic Imaging
    Authors: Bo Wei, Ambuj Varshney, Wen Hu, Neal Patwari, Thiemo Voigt, Chun Tung Chou
    The Fourteenth ACM/IEEE Conference on Information Processing in Sensor Networks(ACM/IEEE IPSN 2015)

My first computer was an IBM PC XT back in 1992. Since 1998, I have been a supporter of the free and open-source software movement and Linux. In 2000-2001, I contributed to the IndLinux project and translated many applications to Hindi. After finishing high school, I created and maintained a popular Linux blog that was ranked in the top 10 in its genre. I used the revenue from advertisements (Google Adsense) to partially fund my undergraduate education.