Towards SDN-enabled RACH-less Make-before-break Handover in C-V2X Scenarios

Future vehicular applications will rely on communication between vehicles and other devices in their vicinity. Technologies, such as LTE-V2X, are awaited to operate under the Cellular Vehicle-to-Everything (C-V2X) standard to make this communication possible. However, current LTE technology has to go through transformations to enhance its performance in vehicular communications. One possible enhancement for LTE is the usage of the latest handover schemes, such as RACH-less and Make-before-break (MBB), to create seamless mobility. In the current study, we propose a RACH-less MBB handover scheme using Software-Defined Networks (SDN). Our main contributions are: (i) unifying lower layer handover operations with controller network updating procedures; and (ii) creating a signaling protocol that allows base stations and controllers to exchange information needed for timing alignment of the UE without executing a RACH procedure. Simulation results show that our proposed handover scheme has a shorter execution time and reasonable signaling overhead when compared to baseline schemes from the literature.