ISAC Architecture and Sensing Topology Switching in 6G Cellular Networks

Integrated sensing and communication (ISAC) is one of the candidate technologies with promising potential for the sixth generation ($6 \mathbf{G}$) of wireless networks. This article presents an overview and comparison of the sensing topologies considered for ISAC: monostatic, quasi-monostatic, bistatic and multistatic. We also describe the ISAC architecture with control and processing functions and introduce a new framework that allows topology switching. The proposed switching framework uses the sensing results of a sensing session to assist the ISAC control function to decide whether the current topology should be retained or switched to a different one, in order to maintain optimal sensing performance. Using simulations, we compare various sensing performance indicators, such as received power and angle-ofarrival estimates, across ISAC topologies that are candidates for switching. According to our simulation results, switching to the bistatic sensing topology delivers the best performance, considering deployment and radio conditions.