5G deployments are now underway across the globe but are merely the first steps in a multi-year journey for the mobile industry. Many practical challenges still remain, not least of which is the challenge of cost-effectively deploying 5G Radio Access Networks (RANs) at scale and assuring the performance of supported 5G services.
The 5G RAN architecture provides an open, virtual, packet-based network that extendsfrom the core to the radio antenna. The virtual architecture of 5G RAN with network slicing and new functional elements, such as the Central Unit (CU) and Distributed Unit (DU), enables multiple demanding services to share the same infrastructure without compromising on their specific performance requirements. Virtual, packet-based RANs also enable network sharing over open interfaces as well as multi-vendor implementations, both of which are important to the 5G business case.
Hardware appliances, such as the Remote Radio Head and Baseband Unit of 4G LTE are now replaced with virtual software running on whitebox or Commercial Off-The-Shelf (COTS) hardware. In 5G, the Baseband Unit is split into two new functions, namely the CU and DU. Both these functions can be located either close to the 5G core or close to the Radio Unit (RU) to meet latency and backhaul requirements. This leads to a much more dynamic fronthaul, midhaul and backhaul network, which is now collectively referred to as the 5G cross-haul or “X-haul” network.
