SCF launches FAPIv7: Enhancing 5G small cell performance and interoperability

Latest upgrades to SCF’s 5G FAPI suite advance interoperability, improve O-RAN ALLIANCE Open Fronthaul support, ease small cell deployments and accelerate massive MIMO features.

London, UK, 23 August 2023 – Small Cell Forum (SCF) continues to advance its 5G FAPI specifications with the release of FAPIv7, a comprehensive update that brings significant enhancements to its core FAPI suite. This release not only underscores SCF’s commitment to advancing small cell and 5G technologies but also demonstrates its dedication to fostering interoperability and accelerating essential advanced cellular features such as massive MIMO (multiple input multiple output).

The key documents within the FAPIv7 release are:

  • SCF-222: 5G FAPI: PHY API specifications
  • SCF-223: 5G FAPI: P19 RF and digital frontend control API
  • SCF-224: 5G FAPI: Network monitor mode API
  • SCF-229: FAPI operations, administration and maintenance (OAM) protocol for inline high-PHY

SCF FAPI specifications have always maintained a high level of quality advanced engineering support, while incorporating market-driven features, and FAPIv7 continues this trend with a series of impactful improvements.

Impact on massive MIMO features: In the realm of massive MIMO, FAPIv7 introduces significant enhancements through updates in SCF-222 and SCF-229 documents:

  • SCF-222 brings forward a refined approach to interoperability, boasting elegant and concise support for backward compatibility and unambiguous tunnelling of 3GPP data and control payloads. Furthermore, acceleration-friendly CSI (channel state information) data structures push the massive MIMO envelope, empowering advanced capabilities for enhanced wireless performance.
  • SCF-229, crucial for fronthaul visibility, adopts a subscription and notification framework based on well-recognized RFCs 8639/8641, along with data tree augmentations for fronthaul counter collection. Moreover, explicit mapping now identifies SCF and O-RAN ports for single and multiple TRPs (transmission and reception points), bolstering efficiency and simplification in complex deployments.

Enhancing small cell performance: FAPI’s impact on small cell performance also receives a boost through revisions in SCF-223 and SCF-224:

  • SCF-223, focusing on digital front end (DFE) signalling, introduces upgrades for OTA (over-the-air) timing and FFT (fast Fourier transform) operation, leading to improved signal processing and efficiency in small cell operations.
  • SCF-224, the network monitor mode (NMM) API, undergoes a substantial upgrade in FAPIv7, featuring the addition of state-control messages and procedures, capability polling, corrections, and message structure simplifications. This comprehensive overhaul enhances the effectiveness of network monitoring in small cell deployments.

Leading SCF member companies have played a pivotal role in the development of these upgraded specifications, including Qualcomm Inc., Picocom, Mavenir, Marvell, Radisys and Reliance Jio.

Andrei Radulescu, FAPI Rapporteur and Senior Staff Engineer at Qualcomm Technologies, Inc., emphasizes the importance of SCF’s ongoing efforts: “The FAPI interface, evolving under the guidance of Small Cell Forum, is a vital enabler for RAN disaggregation and the transition to open network architectures. FAPI’s role in modularizing the network while fostering an open ecosystem is pivotal. The alignment with 3GPP roadmap and O-RAN interfaces demonstrates the significance of these specifications for the industry.”

As the small cell landscape continues to evolve, SCF remains dedicated to driving progress, and FAPIv7 continues to advance the technology roadmap, bringing improved performance, interoperability, and efficiency to the forefront of 5G small cell deployments.