Virtualization is one of the hottest topics of discussion in telecoms today. Enabled by NFV (Network Functions Virtualization) and SDN (Software Defined Networking), virtualization promises to deliver a revolution that will free operators from dedicated hardware, allowing them to cut costs at the same time as providing a more flexible and scalable network.
A recent report by SNS Research forecasts that nearly $20 billion will be invested in NFV and SDN by network operators by the end of 2020, driven by potential CAPEX and OPEX savings. Most network operators have already made some steps towards virtualization, but these have currently not progressed very far beyond the proof of concept (PoC) phase. Vodafone, for example, reported at last month’s Big Communications Event in Austin, Texas, that it had already undertaken a multi-vendor PoC for its planned new enterprise service, VPN+, but that work was continuing in order to bring supplier relationships to the required level.
NFV allows upper layer functions and services to be hosted as Virtual Network Functions (VNF) on standard servers, rather than in dedicated vendor hardware as in a traditional network. The concept of NFV is closely tied in with centralized RAN or Cloud RAN (C-RAN), where all the control functions of the RAN (Radio Access Network) are centralized in servers, leaving just the remote radio heads and time-critical components of the RAN at the cell site, connected to the other components via high-speed optical fibre.
But what impact will NFV have on SON, and what challenges will it bring? The analytics of traditional optimization and SON systems make assumptions about the network topology, cell location, and element hierarchies, all of which are undergoing massive changes as they are migrated to a virtualized framework. Some of the elements will become obsolete, while new ones will be introduced, and therefore the types of data that can be extracted from the network will be rather different. A new approach, and some radical changes, will be required if SON systems are to be able to adapt to this new ecosystem.
With both the EPC (Evolved Packet Core) and the RAN largely residing in Virtual Machines, where will be the RF sensors that provide the data for optimization? The third component of the network—the policy, identity and charging infrastructure—can provide the answer. Although this is also being virtualized, the Call Detail Records (CDR) can easily be accessed, crowd-sourced, and used as the basis for customer-experience based SON.