Towards Reliable mmWave 6G RAN: Reconfigurable Surfaces, Smart Repeaters, or Both?

Mm-Wave 5G NR promises to provide unprecedented access throughput to mobile radio networks but comes with several challenges. Network densification is the only viable solution to increase robustness in front of link outages due to random obstacles. While Integrated-Access-and-Backhauling (IA B) architecture is commonly considered the enabling technology to reduce the cost of such dense deployments, Reconfigurable Intelligent Surfaces (RISs) and Smart Repeaters (SRs) are very recently emerging as promising tools to provide further capabilities to 6G networks in Smart Radio Environments. However, the impact of these devices on next-generation networks is yet to be fully understood. In this paper, we provide a first answer to the questions arising in the deployment of mmWave RAN equipped with SRs and RISs. By means of mathematical programming models for full network planning optimization, we produce optimal network layouts that we leverage to assess in which scenario, in which position, and with which configuration SRs and RISs can better improve the reliability of such networks.