A method for attaching a first radio base station (RBS) to a core network via a radio access network (RAN), wherein a forwarding of data within the RAN is being controlled by a Software Defined Network, SDN, Controller, the RAN comprising a plurality of further RBSs being capable of providing radio connection to a plurality of UEs, and being under the control of the SDN Controller. At least one UE from the plurality of UEs is selected, wherein the selected at least one UE is located within an overlapping radio connectivity area of the first RBS and one of the further RBSs, denoted as a second RBS. The SDN Controller activates control onto the at least one selected UE. The SDN Controller connects the first RBS to the second RBS via the radio connections of the at least one selected UE. The SDN Controller enables the forwarding of data between the first RBS and the core network via the second RBS.