At mmWave frequencies, signal blockage by objects is a substantial limiting factor to achieve dependability. However, the narrow beams possible with mmWave links are an advantage for indoor (e.g., industrial) scenarios, since they allow to reduce interference with neighboring cells when appropriately coordinated. Recent interest from the industry shows that mmWave links are considered a promising candidate to establish industrial networks and enable dependable data exchange between robots indoors. To overcome signal blockage we will investigate RISs to establish controlled wireless wave propagation paths, sidestepping blocking objects.
We developed a worldwide unique active RIS prototype in cooperation with Siemens and performed calibration measurements using the AIT software defined radio (SDR) test systems [Rad24]. A numerical simulation tool for RIS radio wave propagation was developed, achieving excellent agreement with measurement data.
Using a semi-anechoic room in Giefinggasse 4 industrial automation scenarios can be investigated. An extension of our geometry-based channel model for RIS to the mmWave frequency range allows the investigation of adaptive RIS control algorithms for reliable communication with mobile devices in an industrial manufacturing scenario [Rad24a].
Finally, for unknown user equipment position AIT developed an iterative control algorithm for RIS using a single bit feedback that was empirically validated in our RIS lab [Rad26].
[Rad24] H. Radpour, M. Hofer, L. W. Mayer, A. Hofmann, M. Schiefer, and T. Zemen, "Active reconfigurable intelligent surface for the millimeter-wave frequency band: Design and measurement results," in IEEE Wireless Communications and Networking Conference (WCNC), Dubai, United Arab Emirates, April 2024.
[Rad24a] H. Radpour, M. Hofer, D. Löschenbrand, L. W. Mayer, A. Hofmann, M. Schiefer, and T. Zemen, "Reconfigurable intelligent surface for indoor industrial automation: mmWave propagation measurement, simulation, and control algorithm requirements," in IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Valencia, Spain, September 2024.
[Rad26] Hamed Radpour, Markus Hofer, and Thomas Zemen, “Adaptive RIS control for mobile mmWave NLoS communication using single-bit feedback,” in Wireless Communications and Networking Conference Workshops (WCNCW), Kuala Lumpur, Malaysia, April 2026.
