5G PRS-Based Sensing: A Sensing ReferenceSignal Approach for Joint Sensing andCommunication System
The emerging joint sensing and communication (JSC) technology is expected to support new applications andservices, such as autonomous driving and extended reality (XR), in the future wireless communication systems.Pilot (or reference) signals in wireless communications usually have good passive detection performance, stronganti-noise capability and good auto-correlation characteristics, hence they bear the potential for applying in radarsensing. In this paper, we investigate how to apply the positioning reference signal (PRS) of the 5th generation(5G) mobile communications in radar sensing. This approach has the unique benefit of compatibility with the mostadvanced mobile communication system available so far. Thus, the PRS can be regarded as a sensing referencesignal to simultaneously realize the functions of radar sensing, communication and positioning in a convenientmanner. Firstly, we propose a PRS based radar sensing scheme and analyze its range and velocity estimationperformance, based on which we propose a method that improves the accuracy of velocity estimation by usingmultiple frames. Furthermore, the Cr´amer-Rao lower bound (CRLB) of the range and velocity estimation for PRSbased radar sensing and the CRLB of the range estimation for PRS based positioning are derived. Our analysisand simulation results demonstrate the feasibility and superiority of PRS over other pilot signals in radar sensing.Finally, some suggestions for the future 5G-Advanced and 6th generation (6G) frame structure design containingthe sensing reference signal are derived based on our study.