Characterization of Monostatic Base Stations Sensing Resolution Using 5G Reference Signals

Sensing is poised to be a crucial feature in 6G, leading 3GPP to integrate sensing capabilities into the 5G New Radio (NR) framework. Significant progress has been made, but extensive work remains in defining architectures, protocol operations, and deployment strategies. Successful adoption by operators hinges on balancing cost-effectiveness with anticipated benefits. We introduce a novel architecture that repurposes existing 3GPP signals—Synchronization Signal Blocks (SSBs) and Positioning Reference Signals (PRSs)—for monostatic sensing at base stations (BSs), leveraging existing infrastructure to efficiently enhance capabilities.Given that sensing must coexist with communication in 5G systems, resource management is critical. It restricts available resources for sensing, thus limiting resolution. By fusing data from multiple BSs and processing it centrally, significant enhancements in sensing resolution are possible. This paper quantifies the resolution of monostatic and multi-monostatic BS systems by examining the spatial resolution area (SRA)—the region within which the system cannot differentiate between two objects—and localization resolution (LR), defined as the maximum distance error between a target’s estimated and actual positions.Our results show that in the FR1 band, using multiple monostatic BSs significantly enhances system resolution over a single BS setup. Adding a second BS improves SRA by at least 40 %. Employing larger bandwidths up to 100 MHz for PRSs achieves sub-1-meter LR with five BSs, while narrower bandwidths like 7.2 MHz for SSBs approach sub-10-meter LR with seven monostatic BSs.