HIERARCHICAL SOFTWARE-DEFINED NETWORKING ARCHITECTURE FOR NEXT-GENERATION MOBILITY MANAGEMENT

Achieving Ultra-Reliable Low-Latency Communication (URLLC) in mobility scenarios for 5G or next-generation mobile networks is challenged by the dense deployment of small cells and the high frequency of handovers. Traditional 3GPP mobility protocols and existing centralized Software-Defined Networking (SDN) architectures suffer from signaling overhead and handover delay due to relying on the top-down orchestration of forwarding path changes. To overcome this fundamental limitation, we propose an architecture of hierarchical controllers that utilize a novel bottom-up orchestration strategy for mobility support. In this bottom-up orchestration, geographically located hierarchical controllers collocated with base stations can trigger handover execution, allowing target base stations to push user plane forwarding rules up the hierarchy. Through numerical analyses, we validate that our proposed hierarchical controller architecture and bottom-up orchestration reduces network bandwidth consumption for handover signaling by 55% and handover delay by 47% compared to the traditional tunneling-based mobility management method. The results support that the proposed architecture and orchestration mechanism can be a viable solution to provide efficient mobility support in 5G or next-generation dense cellular networks.