Exploiting flexible functional split in converged software defined access networks

5G targets to offer a huge network capacity to support the expected unprecedented traffic growth due mainly to mobile and machine-type services. Thus, the 5G access network has to comply with very challenging architectural requirements. Mobile network scalability is achieved by playing appropriately with the centralization of network functions and by applying the functional split introducing the fronthaul. Although more advantageous in terms of network management and performance optimization, low-layer functional split options require larger bandwidth and lower latency to be guaranteed by the fronthaul in the access network, while preserving other concurrent fiber-to-the-x services. Thus, advanced mechanisms for the efficient management of available resources in the access network are required to control jointly both radio and optical domains. Softwarized mobile and optical segments facilitate the introduction of dedicated protocols to enable the inter-working of the two control planes. This paper proposes a new cooperation scheme to manage the adaptive flexible functional split in 5G networks conditioned to the resource availability in the optical access network. Techniques for the accurate estimation of available bandwidth and the associated real-time selection of the best suitable functional split option are investigated. Results show that the proposed software defined converged approach to wavelength and bandwidth management guarantees the optimal allocation of optical resources. The triple exponential smoothing forecasting technique enables efficient coexistence of mobile fronthaul and fixed connectivity traffic in the network, reducing traffic impairments with respect to other well-known forecasting techniques, while keeping the same level of centralization.