25 Years of 3GPP Charging — From Cork to 6G

Celebrating a quarter of a century of telecom monetization innovation, collaboration and convergence

This October, members of the 3GPP Service and System Aspects Working Group 5 (SA5) will assemble once again to celebrate something remarkable: the 25th anniversary of the first SA5 Charging ad hoc meeting in Cork, Ireland, 16–18 May 2000.

That small gathering of engineers and economists marked the starting point of a journey that continues to shape how every mobile network on earth turns connectivity into value.

From Cork to the Core: The Early Years

When 3GPP’s SA5 was formed in 1999, its mission was to define telecom management under the FCAPS model — Fault, Configuration, Accounting, Performance, Security and Subscriber trace. “Accounting” soon evolved into “Charging,” and within months, a dedicated team emerged to address the business side of telecom operations.

The first SA5 Charging Ad-Hoc, convened in Cork, set out to harmonize how usage records would be created, transferred and trusted across GSM and early UMTS networks. In case you’ve forgotten, usage records in those days recorded voice and messaging activity, and that’s about it (ah, memories). The group’s work produced the now famous TS 32-series specifications, covering:

• Offline charging via Call Data Records (CDRs)
• Online charging using real-time Credit Control (the Ro interface, see IETF RFC 4006)
• Reference architectures for Charging Data Functions and billing mediation

Those early Cork whiteboards defined the principles that still underpin telecom monetization today: neutral interfaces, common data structures and end-to-end traceability between usage and payment.

The LTE Era: Preparing for the Future

In their first decade, the Charging Ad-Hoc group met several times each year, evolving specifications alongside new network generations. As LTE emerged, charging had matured into a modular architecture consisting of Online Charging System (OCS) and Charging Gateway Function (CGF) components.

Yet even then, SA5 visionaries could sense another revolution in the air: the move toward virtualized, service-based networks. Charging would have to follow.

The 5G Leap: Converged Charging

In 2016, SA5 began the study TR 32.899 – Charging Management Architecture for 5G Systems, led by a small group of operator and vendor rapporteurs.

Their conclusion was bold: the new future would be best served by unifying online and offline charging, exposing it through APIs and making it part of the new Service-Based Architecture (SBA). This work gave birth to the Converged Charging System (CCS), featuring:

• Charging Function (CHF) as the central API endpoint
• Charging Trigger Function (CTF) at every network node
• Nchf Converged Charging service specified in TS 32.291 and TS 32.298

The dawn of the 5G era transformed charging from a back-office process into a real-time digital service, exposed through APIs, enabling flexible business models and setting the stage for innovative network slicing models. This was the first step towards driving the API economy and reshaping the future of telecom.

Formalization: The SA5 Charging Sub-Working Group

By 2020, charging topics dominated SA5’s agenda, spanning edge computing, IoT, satellite access, private 5G and network slicing.

In 2021, the SA5’s Charging Sub-Working Group (SWG-CH) was formally established in 3GPP with MATRIXX Software’s Gerald Görmer elected as Chair and Huawei’s Chen Shan as Vice Chair.

This move gave a dedicated structure, cadence and leadership to charging. Since then, SWG-CH has become one of 3GPP’s most productive communities, routinely handling more than 25 work and study items per release.

Release 18 → 19: 5G Advanced Monetization Comes of Age

The past few years have been a truly golden era. Release 18 delivered comprehensive charging frameworks for:

• Network Slicing Phase 2 (NSACF and NSSAAF charging)
• Non-Public Networks, Time Sensitive Networking, Multicast/Broadcast
• B2B and Roaming enhancements

Release 19, which will be completed this year, adds the finishing touches to the 5G Advanced charging model:

• CAPIF phases 2 & 3, integrating API-level and service exposure charging
• CHF segmentation, enabling distributed, tenant-aware deployment
• Energy efficiency charging, turning sustainability metrics into measurable business value
• Next-generation RTC and ambient IoT charging, preparing for immersive and sensor-driven experiences

With these achievements, Release 19 is a fitting milestone to celebrate the group’s 25th anniversary: the point where the 5G vision for unified, programmable monetization is complete.

---

Voices Across the Years

“Cork 2000 was the first time we explored a charging architecture that worked across operators. We couldn’t imagine then that it would scale to billions of users.”
— Gerald Görmer, Chair, SA5 Charging Sub-Working Group

From parameter definitions and diagrams for CDR flows written by hand to YAML-based Open APIs on 3GPP Forge, the commitment to precision and collaboration remains unchanged.

Looking Ahead: Charging for 6G and the API Economy

The story does not end with Release 19. Release 20 and the emerging 6G studies will bring new frontiers:

• Charging reliability enhancement, including self-healing, AI-assisted data recovery
• AI/ML charging, monetizing model training and inference services
• Cross-domain and multi-provider charging, enabling federated marketplaces for APIs, energy and compute

As networks become cognitive and services become intent-driven, charging will once again ensure fairness, traceability and trust, relying on the same principles that were first articulated all those years ago in Cork.

A Toast to 25 Years

From Cork 2000 to Berlin, San Diego and Bejing 2025, the SA5 Charging community has embodied the very best of 3GPP: technical rigor, global cooperation and relentless evolution.

Every mobile call placed, every video streamed and every API called that results in a charge owes a debt to this group’s work.

In October 2025, as SA5 Charging declares Release 19 complete and raises a glass to 25 years of collaboration, one message will echo through the room: “From Cork to 6G — we are ready to charge the future.”