Fraunhofer IAF works with partners on energy-efficient AlScN-based edge-cloud mobile system

Solution for energy-saving mobile radio base stations: “EdgeLimit-Green ICT” project enters next phase

Press release /

The “EdgeLimit-Green ICT” project for the realization of energy-saving mobile radio base stations has started. Together with the University of Freiburg and multiple industrial partners, Fraunhofer Institutes IAF and IIS aim to develop and test an energy-efficient edge-cloud system by 2025, making use of AlScN-based components and demand-driven control. The BMBF is funding the project as part of the “Green ICT” initiative.

“EdgeLimit-Green ICT” has started following a successful preliminary project that evaluated innovative semiconductor technologies and application approaches. In the summer of 2021, the preliminary project succeeded in the innovation competition “Green ICT—Electronics for energy-saving information and communication technology" (ICT) of the German Federal Ministry of Education and Research (BMBF). “Energy-efficient microelectronics, as we are developing in ‘EdgeLimit-Green ICT’, exemplifies how new technologies can become more powerful and at the same time conserve resources,” emphasizes Prof. Dr. Rüdiger Quay, project coordinator and executive director of the Fraunhofer Institute for Applied Solid State Physics IAF. The project consortium, which in addition to Fraunhofer IAF includes the Fraunhofer Institute for Integrated Circuits IIS, The Institute for Sustainable Systems Engineering (INATECH) at the University of Freiburg, and partners from industry, now aims to realize its solution for more energy-efficient mobile radio base stations by 2025.

Quay highlights: “The novel power semiconductor components being developed by Fraunhofer IAF, in combination with the intelligent, AI-assisted networking and control of the antenna system designed by Fraunhofer IIS, promise to halve energy losses during millimeter-wave 5G transmission.” The industrial partners in the project network are supporting the project through collaborations in the development of novel high-frequency transistors (Nokia), circuit processing (United Monolithic Semiconductors GmbH, UMS), and the real-world evaluation and transfer of test results (Deutsche Telekom AG).

Savings due to energy-efficient AlScN components and intelligent cloud-edge implementation

On the one hand, the high energy-saving potential of the antenna system that will be developed in “EdgeLimit-Green ICT” results from the superior material properties of the power semiconductor aluminum scandium nitride (AlScN). Researchers at Fraunhofer IAF produce AlScN employing metal-organic chemical vapor deposition (MOCVD) and use the material in building high-electron-mobility transistors (HEMTs). Due to its high current-carrying capacity, AlScN potentially allows significantly higher power density and gain compared to established semiconductors such as silicon, gallium arsenide or gallium nitride.

On the other hand, the savings result from an efficient design of the electronics. Thomas von der Grün, Head of Locating and Communication Systems Department at Fraunhofer IIS, explains: “We are developing an innovative electronics architecture at Fraunhofer IIS to make possible intelligent networking and demand-driven control of the transmitter and receiver modules with the support of artificial intelligence (AI). This provides for a partial shift of processing capacities from the central infrastructure (cloud) to the edge of the network and the implementation of data processing systems.”

AlScN wafer by Fraunhofer IAF
© Fraunhofer IAF
Using the power semiconductor AlScN, Fraunhofer IAF develops energy-efficient ICs and components.

Overall, the combination of energy-efficient components and optimized organization shall reduce the energy losses of the remote radio head (RRH) implemented in “EdgeLimit-Green ICT” by at least 50 %. For this purpose, researchers double the power efficiency at the amplifier level at new frequencies between 26 and 34 GHz, halve the loss in power converters, and implement demand-driven system control.

BMBF funds green ICT for future technologies

Modern ICT such as the new mobile communications standard 5G has significant social and economic value. It not only improves existing performance parameters, for example by enabling faster Internet on smartphones for private individuals through an enhanced mobile broadband connection. It can also pave the way for promising future applications such as the Internet of Things (IoT), autonomous mobility, or industrial automation. Resource-saving technology in this area therefore has a particularly large impact on the carbon footprint of highly developed economies such as Germany and Europe: It lowers the economic and ecological costs of the knowledge-society and makes it globally competitive.

The BMBF is funding the implementation phase of “EdgeLimit-Green ICT” for three years. A preliminary project carried out from October 2020 to June 2021, involving the investigation and design of new semiconductor technologies and development approaches for energy-efficient mobile radio systems, proceeded in cooperation between the Fraunhofer Institutes IAF and IIS and the INATECH of the University of Freiburg. The project consortium prevailed with its concept in a selection of ten renowned research groups and received second place funding to finance the continuation of the project.


The German Federal Ministry of Education and Research (BMBF) funds the project “EdgeLimit-Green ICT”.

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