Latency-aware CU placement/handover in dynamic WDM access-aggregation networks

Centralized radio access networks (C-RANs) have recently been proposed to cope with the unprecedented requirements of future 5G services, in terms of network capacity, latency, service availability, and network coordination. C-RANs are based on the idea of separating baseband signal processing from radio units (RUs), namely, antenna sites in the mobile network, in such a way that baseband processing can eventually be concentrated in common locations, the central units (CUs), which can be shared among several RUs. Although C-RAN brings significant CapEx/OpEx savings, it also requires transport of high-capacity and low-latency front-haul traffic. Hence, due to the highly dynamic nature of mobile traffic, proper placement of CUs in the optical accessaggregation network should adapt to spatio-temporal traffic variation while maintaining a high degree of RAN centralization and low service blocking. In this paper, we provide an adaptive latency-aware algorithm for dynamic CU placement in optical access-aggregation networks, which targets the minimization of the number of CUs and also preforms grooming, routing, and wavelength assignment (GRWA) for mobile network traffic demands. When given the possibility to perform CU handover, i.e., to move CUs even when they are active, our algorithm, also in high load situations, provides a low number of CUs compared with fixed CU placement and keeps the blocking probability within an acceptable range.