Integration of Sensing Capabilities into TDD Radio Access Networks for Dynamic Spectrum Sharing

This paper presents the concept, development, and validation of an integrated sensing module for Time Division Duplex (TDD) Radio Access Networks (RANs), exploring the guard period inherent in these systems. Our approach achieves a tight integration between the RAN and the sensing node using a lightweight energy-accumulation block that operates during this period. The design allows simultaneous communication and spectrum monitoring, supporting real-time Dynamic Spectrum Sharing (DSS) scenarios. The proposed sensing mechanism enables secondary TDD users to opportunistically access the spectrum without causing interference to primary users. A proof of concept was implemented using an open-source 5G system and a Software-Defined Radio (SDR) transceiver, with results showing a stable RAN performance in the absence of the primary users. This supports the feasibility of embedding sensing into communication systems for future DSS-oriented and Integrated Sensing and Communications (ISAC) applications.