Uplink Power Analysis of RIS-assisted Communication Over Shared Radar Spectrum

The wide deployment of wireless sensor networks has two limiting factors: the power-limited sensors and the congested radio frequency spectrum. A promising way to reduce the transmission power of sensors, and consequently prolonging their lifetime, is deploying reconfigurable intelligent surfaces (RISs) that passively beamform the sensors transmission to remote data centers. Furthermore, spectrum limitation can be overcome by spectrum sharing between sensors and radars. This paper utilizes tools from stochastic geometry to characterize the power reduction in sensors due to utilizing RISs in a shared spectrum with radars. We show that allowing RIS-assisted communication reduces the power consumption of the sensor nodes, and that the power reduction increases with the RISs density. Furthermore, we show that radars with narrow beamwidths allow more power saving for the sensor nodes in its vicinity.