PhD Scholarship: Sunlight-Backscatter Communication for Maintenance-Free Environmental Sensing

About the Project

With wildfires costing New Zealand an estimated $142 million in a single year, this project will address a key part of that challenge: the difficulty of gathering real-time monitoring data from remote, off-grid environments where risk is often highest.

Vast remote regions, from alpine parks to working farmland, often lack the terrestrial infrastructure for reliable data collection, leaving persistent gaps in environmental monitoring, resource management, and public safety.

Bridging these gaps is uniquely difficult because any solution must overcome three compounding constraints at once:

• Scarce Power: Devices must be maintenance-free, commonly operating within a sub-10 mW budget.
• No Dependable Infrastructure: There are no cell towers or Wi-Fi backhaul.
• Unpredictable Link Dynamics: The physical medium is uncontrolled and highly variable, making it extremely difficult to maintain a robust and persistent communication link.

The Research Vision: Communicate Using Sunlight

Conventional approaches, like satellite and terrestrial RF, fail because they are too power-hungry or lack reliable coverage. This project explores a fundamentally different path: communicating by reflecting and modulating light that is already present in the environment. This method allows for dramatic energy savings because, by using sunlight itself as its carrier, the device never has to generate its own power-hungry carrier signal. However, the carrier itself, the sun, is completely uncontrollable. The overarching research question is therefore: How can we build a robust communication link on top of an unreliable carrier?

You will lead a systems-level investigation to turn this concept into a resilient, interactive, and high-performance sensing system. This is a "full-stack" PhD, providing you with deep, hands-on training that connects fundamental theory to real-world deployment. Your work will span low-power circuits, embedded firmware, communication protocols, simulation, and rigorous field experimentation.

Your research will focus on solving three central challenges:

1. The Reliability Challenge. How can a tiny, low-power sensor stay "locked on" to its target when the sun and clouds are always moving? Your work will explore the fundamental trade-offs between actively tracking the light and designing novel passive ways to stay aligned.
2. The Interactivity Challenge. How can a user, like a park ranger or farmer, get data from an autonomous sensor without draining its tiny battery? You will solve this by designing an ultra-low-power "wake-up" system that allows a user to initiate an on-demand, ad-hoc data exchange.
3. The Validation Challenge. How does this system perform at scale and over time? You will first build a network-level model to simulate performance under real-world light dynamics. Next, you will move from simulation to reality, conducting outdoor field deployments to rigorously demonstrate the system's reliability and performance.

Who We’re Looking For

This project is fundamentally multidisciplinary. We are looking for a creative and hands-on researcher. The ideal candidate is someone who is excited to work at the intersection of hardware, software, and communication theory to build a complete, end-to-end system.

While we don't expect expertise in all areas, you will be well-prepared for this PhD if you have:

• A strong foundation in at least one of our core technical areas:
  • Hardware: Low-power circuits, analog/digital design, embedded systems.
  • Communications: Wireless protocols, signal processing, or optics.
  • Software: Strong programming skills for modeling, simulation, and data analysis
• A "hands-on" mindset, with a clear interest in designing, building, and testing real-world systems.
• A drive to solve hard problems. You are motivated by complex challenges and by the process of connecting new design concepts to rigorous field experimentation.

The Opportunity

This is a fully-funded, three-year PhD position based in the school of Computer Science at University of Auckland. Applications from both domestic and international candidates are welcome. The successful applicant will receive a PhD scholarship of NZ$34,569 stipend per annum plus coverage of tuition fees. Additional funding is also provided to support your research, including travel to attend conferences and visit collaborators.

You will be supervised by Dr. Talia Xu at the University of Auckland and will work in close collaboration with Prof. Wen Hu (UNSW Sydney). This structure is a key feature of the project, providing you with dedicated mentorship and access to the combined expertise and resources of two world-class institutions.

We encourage applications from candidates with a strong background in computer and electrical engineering, computer science, physics, or a related field.

To apply, please email the following three items directly to the main supervisor, Dr. Talia Xu (talia.xu (at) auckland.ac.nz):

• A brief statement of interest (1 page): Please explain why you are interested in this specific project and how your skills and background are a good fit.
• A CV
• A copy of your academic transcript(s).