Small Cell Forum has released a study that links small cell design methods with emerging 5G Non-Terrestrial Networks, including low Earth orbit satellite systems.
The report sets out how existing small cell architectures and open interfaces could reduce complexity in satellite-based 5G networks. It also suggests ways these tools could support interoperability between satellite and terrestrial systems.
Non-Terrestrial Networks are an emerging part of the 5G landscape. They use satellite or airborne platforms for mobile connectivity instead of ground-based towers alone.
The report highlights parallels between small cell networks and 5G NTN platforms. It notes that both types of system must meet strict size, weight and power limits.
It says compact radio units are a feature in both domains. It also says modular architectures and standardised interfaces are common design priorities.
SCF argues that its existing technical work has direct relevance for space-based systems. It says these components and frameworks can be reused or adapted for satellite payloads.
The study also looks at hybrid deployments. These combine terrestrial small cell networks with satellite links in a single architecture.
"The connection between SCNs and NTNs is an important but not an obvious one, which has often been overlooked in the industry. This report clarifies the common aspects and shared challenges between them, which in turn highlights where common solutions can be applied. We hope this work will be useful to industry organisations, standards bodies, regulators and policymakers. I am grateful to the SCF team for producing this report and the related earlier publication," said Prabhakar Chitrapu, PhD, Chair, Small Cell Forum.
The new work centres on regenerative 5G NTN systems. These place 5G processing functions on the satellite rather than relying only on ground gateways.
SCF says small cell experience is relevant for these payloads. It points to areas such as software-defined radios, split architectures and open RAN-style interfaces.
Industry guidance
The report comes as satellite-based 5G experiments move into more commercial testing. Vendors and operators are developing new architectures for NTN services.
"5G NTN represents a fast-moving area of innovation and there is a clear need for practical guidance as new architectures take shape. This paper shows how experience from the small cell ecosystem can be applied to support regenerative payload design, simplify interface integration and help vendors and operators progress toward interoperable 5G NTN implementations," said Vicky Messer, VP Product Management, RANsemi, and Co-Lead of the SCF NTN Work Item.
SCF members produced the report. Contributors include RANsemi and AccelerComm as document co-editors, along with Radisys, Reliance Jio, Microamp, Marvell and BT. Reviewers from Qualcomm and Druid Software also took part.
The study outlines several target use cases for NTN-based 5G. These include remote coverage extension, emergency communications, transportation and industrial services.
It describes the main technical challenges for 5G NTN platforms. These include long signal delay, Doppler effects from moving satellites and beam mobility as coverage areas shift.
The report lists mitigation strategies that already exist in current standards. It says these can address delay, frequency shifts and moving beams in different ways.
Standards alignment
The paper reviews 3GPP activities on NTNs. It matches these developments against SCF's own work on open interfaces.
It highlights FAPI and nFAPI as relevant tools. These are interface frameworks that support disaggregated, multi-vendor network elements.
SCF says these interfaces can extend into the NTN domain. It says this would support 5G systems that mix satellite and terrestrial components from different suppliers.
The report argues that standardised interfaces are important in a hybrid environment. It says they give operators a basis for interoperability between ground networks and satellite payloads.
Case studies in the paper describe early NTN demonstrations. These show how existing 5G access networks and user equipment can operate over satellite links.
SCF notes that current tests already use standard 5G handsets and radio units. It says improvements in satellite transport capacity will increase service quality over time.
Next steps
The report sets out a list of priority areas for future work inside SCF. These include new specifications and deployment frameworks aligned with NTN plans.
One focus is the addition of 5G NTN features into upcoming FAPI releases. Another is the evolution of shared infrastructure models that include satellite integration.
SCF says this roadmap will give suppliers and operators a clearer route for NTN development. It aims for NTN systems that share as much common structure as possible with terrestrial 5G networks.
"This paper shows how experience from the small cell ecosystem can be applied to support regenerative payload design, simplify interface integration and help vendors and operators progress toward interoperable 5G NTN implementations," said Messer.