Renesas Network Synchronizer Solutions for 5G O-RAN Systems

Traditional Radio Access Network (RAN) equipment used in 2G, 3G, 4G, and early 5G cellular networks have been provided as a single black box solution to operators using internal interfaces that were proprietary to each vendor and non-standard. Such implementations led to operational efficiencies and cellular operators getting locked-in to specific vendor solutions across the cellular generations. By enabling an open, multi-vendor RAN ecosystem, O-RAN introduces a more flexible RAN architecture by decoupling hardware and software through the application of network function virtualization (NFV) principles. The different functions of the base station is now split into the following entities with open interfaces between them: a centralized unit (CU), a distributed unit (DU), and a radio unit (RU). Such an approach also enables faster time-to-market compared to traditional RAN.

Despite aforementioned advantages, guaranteeing system performance and managing complexity are inherent challenges of the O-RAN approach. In practice, the responsibility for validating and deploying systems will fall on cellular operators themselves – either directly, or through partnerships with Systems Integrators (SI). With multiple system integrators in play, silicon vendors often bear the responsibility to minimize the overall system complexity and guarantee performance of individual components.As the O-RAN approach is intended to deliver the full range of enhanced capabilities available with newer 5G network equipment, the fundamental need to guarantee synchronization, with strict timing requirements, remains.