The above problem rewarding Numerology may occur also in other E-UTRA-NR DC architecture options (e.g., architecture options 7 and 7A). The architecture options 7 and 7A are Dual connectivity (DC) deployments including E-UTRA serving as the anchor RAT (or the primary RAT or the master RAT) and NR serving as the secondary RAT. In the options 7 and 7A, E-UTRA (LIE eNB) and NR (gNB) are connected to the 5G-CN. The NR user plane connection to the 5G-CN goes through the LIE eNB in the option 7, whereas in the option 7A, it directly passes through the user plane interface between the gNB and the 5G-CN. In the options 7 and 7A as well, it is also not clear how to perform a radio resource configuration regarding numerology of the SCG cell (or SCG carrier) on the UE when the SgNB supports multiple numerologies and the UE uses them.

A similar problem regarding Numerology may occur also in an Inter-RAT handover from E-UTRA to NR. That is, it is not clear how to perform a radio resource configuration regarding numerology of the target NR cell on the UE when the UE is handed over from the source LTE eNB to the target gNB that supports multiple numerologies.

Accordingly, one of the objects to be attained by embodiments disclosed herein is to provide an apparatus, a method, and a program that allow a UE to be configured with a numerology of a cell served by a secondary gNB or a target gNB in Inter-RAT Dual Connectivity between E-UTRA and NR and in an Inter-RAT handover from E-UTRA to NR. It should be noted that this object is merely one of the objects to be attained by the embodiments disclosed herein. Other objects or problems and novel features will be made apparent from the following description and the accompanying drawings.