I. Introduction
Compared to previous generations of cellular networks, 5G manifests the flexibility to support a wide range of heterogeneous applications, control and data plane separation as well as the introduction of a service-oriented architecture [1]. To cater for the aforementioned requirements, Software-Defined Networking (SDN) has become crucial in the core network [2], [3], [4]. Similarly, for the Radio Access Network (RAN) counterpart, softwarization [5], [6] and virtualization [7], [8], [9] are envisioned as the main drivers to fulfill the anticipated 5G design principles.