I am a PhD student in the WCSNG lab at UCSD, advised by Prof. Dinesh Bharadia. I study signal processing for radar and sensing applications. Broadly, I am interested in timing and channel estimation techniques, and in using these techniques to solve unconventional and challenging sensing problems. I also enjoy embedded hardware development, and implementing my projects in the cheapest and most scalable way possible.
Research & Publications
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PHASOR: Enabling New Wireless Sensing Applications with Wi-Fi Phase Synchronization
Indoor Wi-Fi access points are unsynchronized, so channel measurements from different receivers can’t be coherently combined, which limits how well the infrastructure can be used for sensing. PHASOR pairs an ESP32 with a controllable TCXO and uses standard FTM exchanges between nodes to phase-synchronize spatially separated commodity Wi-Fi receivers entirely over the air, effectively building a distributed phased array. It achieves sub-nanosecond time synchronization over a standard Wi-Fi link, which we use to build an accurate indoor localization system, and it can also serve as a precise synchronized clock source for external devices like network switches and SDRs.
Hunter, W.*, Nguyen, K.*, Kizaki, K., Saruwatari, S., and Bharadia, D. (2026). Preprint, under review. *Equal contribution.
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Wi-PRO: Accurate Indoor PNT using FTM with Multipath Suppression
802.11mc (FTM Ranging) has been standardized in Wi-Fi for a few years now, but we see very few commercial products using it. This is because most open FTM implementations have extremely poor empirical performance indoors, due to multipath. In this work, I show that you can use CIR measurements exposed by the ESP32 with a simple leading-edge detection algorithm to cancel the effect of multipath, and obtain a 3-4x improvement in range error over the ESP32’s implementation. I have also released a toolbox along with the paper so others can experiment with wireless localization systems on the ESP32.
Hunter, W., Ayyalasomayajula, R., and Bharadia, D. (2026). IEEE International Symposium on Dynamic Spectrum Access Networks (DySPAN '26)
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WiSenseHub: Architecture to deploy a building-scale Wi-Fi Sensing System
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WAIS: Leveraging WiFi for Resource-Efficient SLAM
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Demo Abstract: Accessible WiFi sensing leveraging Robot Operating System
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P2SLAM: Bearing based WiFi SLAM for Indoor Robots
Arun, A., Ayyalasomayajula, R., Hunter, W., and Bharadia, D. (2022). IEEE Robotics and Automation Letters
