Doctoral theses of the School of Electrical Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence, Communications Engineering and Networking Technology, MSc Jingyi Liao
Turning existing mobile networks into communication infrastructure for battery-free devices.
Public defence from the Aalto University School of Electrical Engineering, Department of Information and Communications Engineering.
Public defence from the Aalto University School of Electrical Engineering, Department of Information and Communications Engineering.
In this event, we are committed ºÚÁÏÍø University’s principles for a safer space.
Title of the thesis: Ambient Backscatter Communications in Cellular Systems
Thesis defender: Jingyi Liao
Opponent: Prof. Jari Nurmi, Tampere University
Custos: Prof. Riku Jäntti Aalto University School of Electrical Engineering
Future Internet of Things applications may involve tens of billions of connected devices. Supplying energy to such a large number of sensors using batteries would be costly, environmentally unsustainable, and in many cases impractical. This doctoral dissertation investigates how battery-free devices can communicate by reusing radio signals that already exist in the environment.
The research focuses on ambient backscatter communication, a technology in which devices transmit information by reflecting existing radio waves instead of generating their own wireless signals. While previous studies have mainly considered dedicated radio carriers or non-cellular signals such as television broadcasts and Wi-Fi transmissions, this dissertation investigates how existing 4G LTE and 5G mobile networks themselves can become communication infrastructure for battery-free devices.
The work develops signal processing methods that allow extremely weak backscattered signals to be detected in the presence of much stronger cellular transmissions. The proposed techniques are validated through theoretical analysis, computer simulations, and real-world prototype experiments using commercial cellular systems.
The results demonstrate that reliable communication is possible without additional spectrum allocation, dedicated infrastructure, or modifications to existing cellular deployments. The findings provide both theoretical foundations and practical design guidelines for integrating battery-free devices into future 6G networks and Ambient Internet of Things systems.
The dissertation contributes to the development of sustainable and maintenance-free wireless technologies, enabling sensors that may operate for years without batteries and become seamlessly embedded into homes, cities, industry, and critical infrastructure.
Thesis available for public display 7 days prior to the defence at .
Doctoral theses of the School of Electrical Engineering
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