Dynamic Virtual Network Connectivity for C-RAN Backhauling

Aiming at satisfying in a cost-effective manner the forecast traffic growth that future mobile networks will need to support, traditional distributed Radio Access Networks (RANs) are evolving towards centralized architectures. Specifically, the Cloud-RAN (C-RAN) architecture has shown that can alleviate to some extent the ever increasing Total Cost of Ownership in mobile networks. The current trend in C-RAN is to separate Remote Radio Heads (RRH) with radio frequency (RF) functions and Baseband Units (BBU) gathering baseband processing. This functional split allows keeping RF modules close to the antennas while placing BBUs at centralized locations so they can be shared among different sites and even be virtualized. However, some issues still need to be addressed in future mobile networks, especially due to the dynamicity of services and the strict constraints imposed by the interfaces needed. Since connectivity reconfiguration for backhaul interfaces (X2 and S1) needs to be provided as an all-or-nothing request to enable mobile resources reconfiguration in a geographical area, in this paper we propose dynamic Customer Virtual Network (CVN) reconfiguration to be supported in metro and core network segments. Additionally, such CVN requests must include Quality of Service constraints to ensure specific delay constraints, as well as bitrate guarantees to avoid service interruption. An efficient algorithm is presented for the CVN reconfiguration problem and exhaustive simulation results study its performance on realistic scenarios.