The evolution of radio communication networks will soon include by so-called “CloudRAN” technologies which refer to centralized radio-access infrastructure deployed in data-centers. Although exhibiting important differences in the type of processing they perform, the compute and storage architecture of these data-centers, as well as many of the software technologies, are very much modelled by those used by internet-based industries for information content management and distribution.

The future network architecture is comprised of three segments, the so-called fronthaul network, the CloudRAN data-centers and the main data-centers. The fronthaul network links the radio nodes at the extremities with the CloudRAN. These interconnection networks are typically optical links over very large distances (10-20 km) when the CloudRAN resides in the central office of an operator. Various technologies are envisaged including analog (radio-over-fiber) PON (passive optical network), TDM and WDM PON and carrier grade optical Ethernet. Other solutions will also exist for indoor networks (e.g. airports, shopping malls, large administrations, private enterprise networks, etc.) using both optical and copper-based fronthaul networks.

The software architecture of OpenAirInterface (OAI) is currently being evolved to cater to these distributed processing environments. In particular the infrastructure processing elements in OAI are being split at various places to allow them to be distributed between the central cloud processing units (RCC), the so-called radio-aggregation units (RAU) which perform centralized signal processing and switching and the network of remote-radio units (RRU). OAI now comprises two such processing splits which will be detailed along with examples of how to build simple ethernet-based RRU with low-cost commodity radio equipment (e.g. USRP B2x0, LimeSDR, etc.) and embedded PCs or ARM-based computers. In addition, The current architecture for deploying OAI in a data-center environment will be described.

A short live demonstration of networked-signal processing for 4G will be provided comprising a USRP-based RRU running on an UPBoard, an ethernet fronthaul and a mini radio-cloud-center housing the access protocol stack and a small core network.