We caught up with Nuno Borges de Carvalho to learn more about him and his team work at Instituto de Telecomunicações in Aveiro, Portugal.
The interview focused on assessing the current dependence of wireless networks on conventional power grids and how your work has addressed this challenge, including the use of alternative energy sources, like, for example, the blackout that occurred in Portugal this past April.
Nuno Borges Carvalho is our senior researcher in the scope of Radio Systems (Wireless Technologies), currently Director of DETI, and Full Professor at the University of Aveiro. He co-invented six patents. His main research interests include software-defined radio front-ends, wireless power transmission, nonlinear distortion analysis in microwave/wireless circuits and systems, and measurement of nonlinear phenomena. He has recently been involved in the design of dedicated radios and systems for newly emerging wireless technologies.
1. How do you assess the current dependence of wireless networks on conventional power grids, and how has your work addressed this challenge, including alternative energy sources?
Current wireless communication networks are primarily designed to deliver high data throughput for digital communications, which results in high energy demands. For example, 5G networks require significantly more energy than previous generations. However, in applications such as IoT, where data rates are often low, energy requirements can be minimal. In such cases, energy harvesting solutions can make a significant difference. Technologies like Wireless Power Transfer (WPT) aim precisely to reduce grid dependency by enabling remote and continuous device charging, even in remote or mobile environments. Furthermore, hybrid generator systems offer added value by integrating WPT with renewable energy sources, such as solar, wind, or piezoelectric generation, to power IoT nodes in isolated areas, thereby creating sustainable microgrids.
2. What would be the main impacts of a prolonged blackout on mobile networks, IoT, and other wireless systems? Are there data or real-world experiences that help anticipate these effects?
A blackout could severely disrupt emergency communications, environmental monitoring, and industrial operations that rely on connected sensors. Real-world examples, such as the Texas blackout in 2021, demonstrated that mobile towers and IoT gateways began failing in under four hours without power. While WPT can help maintain system operations during outages, it still requires an energy source to generate and transmit power, something crucial in scenarios where system uptime is critical.
3. What technological solutions or alternative energy sources have shown the most potential to make wireless networks more resilient to power failures?
Directional WPT with beamforming can remotely power critical devices such as drones, sensors, or medical equipment. These solutions, when combined with RF energy harvesting, enable the collection of ambient RF energy (from Wi-Fi, 5G, etc.) to power low-energy sensors. Integrating solar panels and supercapacitors can further ensure a continuous and reliable energy supply with less degradation over time compared to conventional batteries.
4. What do you consider essential to ensure such resilience?
Resilience depends on localized energy sources—such as solar panels combined with WPT, to power microcells and IoT nodes. Self-generation of energy is crucial to keeping systems operational, especially for critical communications. From an emergency communications perspective, radio broadcast systems are also essential, offering energy-efficient and reliable means to inform the population during crises.
5. How do you envision the future of wireless networks in a scenario of energy scarcity and ecological transition? Do you foresee a paradigm shift?
Ultra-low-power devices powered by ambient RF or environmental energy will form the foundation of more resilient and eco-friendly networks. These developments are likely to drive a paradigm shift, prioritizing sustainability and efficiency over raw performance.
6. Are there any ideas or projects you would highlight as particularly relevant to this discussion?
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