RANsemi & TechPhosis integrate OCUDU for 5G small cells

RANsemi and TechPhosis have integrated the Linux Foundation's OCUDU 5G CU/DU software with RANsemi's commercial 5G PHY using the Small Cell Forum's FAPI interface.

The project combined TechPhosis' RAN software deployment and system integration work with RANsemi's RNS802 baseband system-on-chip platform to create a complete 5G gNB architecture for integrated small cells. The result shows that open-source CU/DU software can operate with a commercial physical layer through an industry-standard interface.

That is significant because OCUDU is more commonly associated with O-RAN deployments based on Split 7.x architectures, while this work applies the software to compact integrated small cell systems. It offers operators and developers a way to use open-source software without giving up the optimisation associated with commercial PHY technology.

Hosted by the Linux Foundation, OCUDU is an open-source centralised unit and distributed unit software platform for 5G and future wireless networks. Unlike proprietary RAN software, open-source platforms do not come with a single vendor responsible for integration, creating an opening for specialist providers that can turn community software into deployable products.

TechPhosis said its role was to bridge that gap through work on RAN Layer 2 and Layer 3 software and broader system integration. RANsemi contributed its RNS802 development platform and PHY software to validate the combined design in a low-power integrated small cell format.

Open RAN link

The project also builds on an existing relationship between the two companies in integrated small cell design. They had previously announced a collaboration to develop an Integrated Small Cell Starter Kit, and this integration adds an open-source CU/DU software layer to that effort.

RANsemi positions its silicon around Open RAN baseband systems for 5G networks, while TechPhosis focuses on CU/DU software and Open RAN integration. By linking OCUDU to a commercial PHY through SCF FAPI, the companies align open-source RAN software with a standard interface already recognised in the small cell market.

The Small Cell Forum's FAPI specification is designed to separate higher-layer software from the physical layer in radio access equipment. Here, the interface allowed OCUDU software and RANsemi's PHY implementation to work together inside a compact small cell design.

Deployment options

The architecture could also extend beyond integrated small cells. The companies pointed to a software path that could support O-RAN 7.2 deployments using RANsemi's RNS805 O-RU chip, giving developers the option to use a similar software approach across both integrated and disaggregated network designs.

That could appeal to customers building private networks, mission-critical systems and defence-related wireless infrastructure, where operators often want flexibility in how networks are assembled and maintained. The companies said standards-based interoperability and open-source software can widen technology choices and simplify deployment in those settings.

"Open source software and standards-based interoperability are becoming increasingly important within wireless infrastructure. This cooperation with TechPhosis illustrates how open ecosystems and commercial wireless technology can work together to create greater flexibility and choice for future wireless infrastructure deployments," said Peter Claydon, Chief Executive Officer of RANsemi.

The companies presented the project as an example of how open-source RAN software can move closer to commercial use when paired with integration expertise and established hardware. For small cell deployments, where size and power constraints are central to network economics, that combination may prove more relevant than broader disaggregated architectures alone.

OCUDU is backed by the Linux Foundation's OCUDU Ecosystem Foundation and is designed to align with 3GPP and O-RAN Alliance specifications. Its availability as an open-source stack gives developers access to a full 5G RAN software base, but practical deployment still depends on how well that software connects to hardware and radio layers.

"Open source software provides an important foundation for innovation, but customers also require enhancements, integration and support. Our joint work with RANsemi shows how open source innovation can be translated into deployable 5G infrastructure, helping customers move from software availability to real-world networks," said Singh.