Ambuj Varshney

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

I lead the Wireless, Embedded Intelligence, Sensing, and Emerging Technologies (WEISER) group—a small, talented team of engineers focused on embedded systems. We engineer systems at the intersection of electronics, communication, computer science, and artificial intelligence. Our approach is bottom‑up: we enjoy designing systems from scratch. Some of our efforts include the development of transmitters, receivers, embedded cameras, language models, sensors, and operating systems.

Our research has been appreciated with several awards including Winning ACM Student Research Competition (Twice!) at MobiCom, support from industry (such as ABB and Google) through their flagship awards, and numerous other publication and demonstration awards.

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News

• May 2025: The work by Pramuka, Rajashekar, and Wenqing (SoMIX), in collaboration with Prof. Prabal Dutta from University of California, Berkeley, has been accepted to ACM MobiSys 2025. The paper presents the design of highly energy-efficient radio receivers (hundreds of microwatts) that enable long-range communication (over 100 meters).
• May 2025: Rajashekar Reddy was selected as one of the Rising Star at the ACM MobiSys 2025.
• April 2025: The work by Rajashekar and Dhairya (AudioCast) on designing low-power audio broadcasting tags leveraging unused spectrum in the FM-broadcast band has been accepted for publication in ACM IMWUT 2025. The system will also be demonstrated at ACM MobiSys 2025, and presented later in the year at UbiComp 2025.
• January 2025: We hosted Prof. Prabal Dutta from the UC Berkeley, in our group as part of NUS Research Week. Prabal gave an exciting talk titled From Wireless Sensors to Pervasive Perpetual Networks". Some photos from the visit: [1], [2], [3]
• May 2024: Nobel Ang received the Best Undergraduate Project award (SoC Innovation Prize 2024) for his project titled “Connecting IoT Devices to Edge and Cloud Systems,” conducted in our research group.
• May 2024: We received the Best Demonstration (Runner-up) award at ACM/IEEE IPSN 2024 (co-located with CPSWeek) for PixelGen . This work was presented by an undergraduate (Kunjun Li) from National University of Singapore.
• April 2024: I received the Google Research Scholar Award for our work on designing battery-free trackers (similar to AirTags). I am the only faculty outside North America to receive this award in Systems and Networking category this year.
• January 2024: Wenqing Yan a student whom I co-supervised with Prof. Christian Rohner successfully defended her dissertation titled Design and Identification of Wireless Transmitters for a Low-power and Secure Internet of Things" . The opponent for the defence was Prof. Haitham Hassanieh (EPFL) and the Committee: Prof. Niki Trigoni (University of Oxford), Prof. Danny Hughes (KU Leuven), and Prof. Mikael Stenard (Uppsala University). You can find the defence video here.
• June 2023: We received the Best Demonstration Award at ACM MobiSys 2023 for demonstrating a platform designed to teach the fundamentals of wireless communication using the backscatter mechanism. This platform was jointly developed with my PhD student Wenqing Yan, Prof. Christian Rohner, and Tobias Mages from Uppsala University, Sweden.
• March 2022: I’ve begun a new chapter in my journey as an Assistant Professor at the National University of Singapore. I’m bootstrapping the WEISER Research Group (Wireless, Embedded Intelligence, Sensing, and Emerging Technologies).
• January 2022: I am serving as a Jury member for selecting of the 2022 ABB Research Award in the Honour of Hubertus von Grünberg. The other members of the selection Jury Includes: Dr. Hubertus von Grünberg, former chair of the board of the ABB Board of Directors, Prof. Nina Thornhill, Imperial College London, Prof. Roland Siegwart, ETH Zurich, Prof. Manfred Morari, University of Pennsylvania, and Dr. Bernhard Eschermann, CTO of ABB Process Automation.

Service

Teaching

I teach courses on wireless networking and embedded systems. Specifically, I have taught CS4222: Wireless Networking and CS5272: Embedded Software Design at the National University of Singapore.

Research

We enjoy building systems. This involves embedded platform design, programming, networking, and real‑world deployments of embedded systems. The required skill set ranges from chip fabrication and programming microcontrollers to developing networking and wireless protocols, distributed computing concepts, machine learning frameworks, and prototyping applications for various scenarios. We categorize our current research in two directions: Tunnel diodes and beyond radio frequency. Our work is interdisciplinary, and we welcome students from diverse backgrounds (EE, ECE, CSE, Physics, etc.).

You can learn more about my research also through these external articles: article from ABB , and article from NUS.

Enabling Long-Range and Low-Power Reception on Embedded Systems.

Low-power Audio Broadcasts on FM-Broadcast Spectrum

Enabling Low-Power, Non Contact Sensing of Breathing Rate using Tunnel Diodes.

Using Li-Fi to enable Low-power RF Transmissions.

Low-power camera working with diffusion models for mixed-reality headsets.

Relaying Li-Fi Transmissions onto RF signals at a Low-power Consumption.

Tunnel-diode Transmitters Communicating at Low-power Consumption on FM-Broadcast band.

An Overview on Designing Low-power Radio Transmitters

Enabling Low-power transmissions over distances exceeding 100 meters.

Fingerprinting the low-power oscillator jitter in backscatter tags.

Battery-free platforms that communicate using RF and Li-Fi.

Enabling Low-power carrier emitters using tunnel diode oscillators.

Battery-free platforms that communicate using RF and Li-Fi.

Using Tunnel Diodes to Enable Low-Power Communication even without Carrier Emitter Device.

Laying out the vision for connecting battery-free devices with Li-Fi and RF-Backscatter.

Low-power receiver based on schottky diodes for receiving IEEE 802.15.4 transmissions.

Overturning the notion that backscatter is a short-range mechanism

Backscatter based Wide-area Networks

Light Sensing at under 20 microwatts. World's first battery-free light sensing and communication system.

Programming Li-Fi transmitter for bringing Visible Light Communication to Embedded Systems.

Device-free localization through a deployment of electronically steerable directional antennas.

Bulk-forwarding through custom designed testbed with electronically steerable directional antennas.

Education

I was a Postdoctoral Scholar at the Department of Electrical Engineering and Computer Sciences (EECS) of the University of California, Berkeley . Prior to that, I completed my doctoral studies with a dissertation titled Enabling Sustainable Networked Embedded Systems" , from the Uppsala University in Sweden. Even before, I was a Software Engineer working at NXP Semiconductors, and before that, graduated with a Bachelors in Informaton and Communication Technology.

My doctoral dissertation was awarded 2019 ABB Research Award in the Honour of Hubertus Von Grunberg . This award included an endowment worth 300,000 USD. The highest of its kind award for early-career researchers by a commercial organization. The endowment was hosted at the Department of EECS at University of California, Berkeley.

Funding

My research has been funded by government agencies (Swedish Innovation Agency, Vetenskapsrådet [Sweden], Ministry of Education[Singapore]), university (ODPRT, ARTIC), and unrestricted gifts or grants from industry (NCS, Google, ABB).