This dataset contains experimental measurements collected from an O-RAN-compliant, multi-cell Beyond-5G communication system deployed on the Four Dot Infinity (FDI) testbed. It provides a comprehensive set of performance metrics evaluated under multiple scenarios, including a baseline configuration with only Additive White Gaussian Noise (AWGN), as well as several 3GPP Tapped Delay Line (TDL) fading channel models, namely TDL-A, TDL-B, TDL-C, TDL-D, and TDL-E. In addition, the dataset incorporates mobility-driven intra-gNB handovers across three New Radio (NR) cells, enabling realistic analysis of UE-to-network interactions under diverse radio propagation conditions. The experimental platform is built on a single srsRAN gNB, where the Central Unit (O-CU) and Distributed Unit (O-DU) functionalities are co-located within the same process. The setup is complemented by the Open5GS core network and the Amarisoft UE simulator, and emulates a total of 24 UEs distributed across three cells, with eight UEs initially assigned to each cell. The radio interface between the gNB and the UE simulator is implemented via the ZeroMQ-based virtual radio, while downlink traffic generated using iperf3 maintains a sustained offered load. Each scenario runs for 30 minutes, with measurements collected at the gNB side at ~1 second intervals. The present dataset uniquely combines multi-cell operation, mobility-driven handovers, and fine-grained DU-low telemetry within the considered O-RAN-compliant experimental environment. This makes it suitable not only for end-to-end performance evaluation but also for detailed analysis of lower-layer processing behavior under realistic channel and mobility conditions. Lastly, the dataset is intended to support research on AI/ML-driven low-level RAN optimization, as well as conventional performance evaluation. It is particularly relevant for studies on MAC and PHY layer algorithms, mobility and handover mechanisms, scheduler behavior, and cross-layer telemetry analysis in controlled multi-cell environments. Further details are provided in the accompanying README.md file included in the compressed archive.