Handover in 5G Non-Terrestrial Networks: From Theory to Experimental Validation

The extension of 5G New Radio to Non-Terrestrial Networks (NTN) makes handover one of the most challenging procedures to support, due to long propagation delays, large Doppler shifts, and fast-moving satellite beams. Before handover can be studied under these conditions, the underlying 5G protocol stack must first be shown to work reliably in a controlled terrestrial setting. This thesis reviews 3GPP NTN architectures and mobility procedures, and then validates handover experimentally on a disaggregated Open RAN testbed. Alog-basedtimingframeworkisintroducedtomeasureandcompare handover latency consistently across three architectures: intra-CU (F1AP), Core-orchestrated(NGAP),anddirectinter-gNB(Xn). Thesameframework is then applied to an initial NTN scenario with emulated LEO satellites. The results show a clear ranking driven by Core Network involvement, characterize the behavior of each architecture under multi-user load, and confirm that the terrestrial baseline extends directly to the non-terrestrial case, providing the foundation for a full NTN validation campaign.