Passive wireless surfaces were long thought to be noiseless, but they actually generate thermal noise that slows down 6G data transmission.
April 23, 2026
Original Paper
Passive RIS Is Not Silent: Revisiting Performance Limits Under Thermal Noise
arXiv · 2604.18263
The Takeaway
Reconfigurable Intelligent Surfaces act like smart mirrors for wireless signals to help 6G networks reach around corners. Engineering models previously treated these passive components as if they added zero noise to the system. Thermal vibrations within the surface material actually create a significant amount of interference that degrades performance. This noise creates a hard limit on how much data can be transmitted through these surfaces. Engineers will now have to redesign 6G infrastructure to account for the fact that even silent components have a voice.
From the abstract
Reconfigurable intelligent surfaces (RISs) have emerged as a promising solution for enabling energy-efficient and flexible spectrum usage in wireless communication, particularly in the context of sixth-generation (6G) networks. While passive RIS architectures are widely regarded as virtually noiseless due to the lack of active components, this idealized assumption can lead to misleading performance evaluations. In this paper, we revisit this assumption and demonstrate that the thermal noise gene