6G denotes the next generation of mobile cellular systems, framed internationally as IMT-2030 by ITU-R and studied in 3GPP from Release 18 (5G Advanced) onward with dedicated 6G work items accelerating in Release 19–21. Commercial deployment is widely targeted for around 2030, following the typical decade-long cycle after 5G (IMT-2020). Unlike incremental 5G releases, 6G research programmes emphasise a native integration of AI/ML in the air interface and the core (not only as an overlay analytics function), Integrated Sensing and Communication (ISAC) — using radio resources jointly for connectivity and environment sensing — and exploration of sub-terahertz and advanced MIMO for extreme capacity and sensing resolution. Energy efficiency, ubiquitous coverage (including NTN/satellite as a first-class component), and trustworthy / resilient network operation are recurring design goals across regional initiatives (Europe’s Hexa-X / Hexa-X-II, Korea’s 6G R&D, Japan’s Beyond 5G, and industry forums such as Next G Alliance in North America).
The 5G Core (5GC) is the packet core network architecture defined by 3GPP from Release 15 onward as the control and user-plane backbone of standalone 5G deployments. It replaces the Evolved Packet Core (EPC) of 4G LTE not through incremental evolution but through a deliberate architectural break: where the EPC was built around monolithic, hardware-bound network functions interconnected by point-to-point interfaces, the 5GC is designed from the ground up around a Service-Based Architecture (SBA) — every network function exposes its capabilities as a set of services over a common HTTP/2 bus (the Service-Based Interface, SBI), and any authorised consumer NF can discover and invoke those services through the NRF (Network Repository Function) without bilateral peering agreements or proprietary protocols. This shift reflects two structural requirements of 5G that EPC could not satisfy: network slicing — the ability to run logically independent end-to-end networks (each with its own QoS, isolation, and lifecycle) on shared physical infrastructure — and cloud-native deployment, where NFs run as containerised microservices on commodity compute, can be horizontally scaled, and are managed by standard Kubernetes-compatible orchestration rather than vendor-specific element managers. The 5GC also enforces a hard separation between Control Plane (CP) and User Plane (UP) — the CUPS principle inherited from 3GPP Release 14 and fully operationalised here — so that the UPF (User Plane Function) handling packet forwarding, QoS enforcement, and traffic anchoring can be distributed to the edge independently of the control logic, enabling ultra-low-latency and MEC scenarios without redesigning the control plane. The architecture is access-agnostic: the same 5GC serves NR (New Radio), eLTE, Wi-Fi (untrusted/trusted non-3GPP access), and fixed-wireless access through a unified N2/N3 reference point toward the access network and a common UE context model in the AMF.
3GPP Security Assurance Specifications (SCAS) are technical specifications developed by 3GPP’s SA3 working group (Security) that define security requirements and associated test cases for specific network product classes — each 3GPP-defined network function (AMF, SMF, UPF, gNB, MME, etc.) has its own SCAS document. 3GPP is the international standards body responsible for mobile telecommunications standards (comprising seven organizational partners covering Europe, US, China, Japan, Korea, India), making SCAS a globally recognized specification set rather than a national or regional scheme. Each SCAS document follows a structured approach: it identifies the assets of the network product class that require protection, performs a threat analysis describing how those assets can be exploited, defines security requirements (objectives) that mitigate the identified threats, and specifies concrete test cases to verify that a product implementation meets those requirements. SCAS specifications serve as the technical foundation for the GSMA NESAS scheme — when a vendor submits a network product for NESAS evaluation, accredited test laboratories evaluate it against the applicable SCAS test cases. Compliance is voluntary (there is no legal mandate to pass SCAS tests), but SCAS/NESAS evaluation results are increasingly used as a procurement requirement by telecom operators and are referenced by the EU 5G Security Toolbox and national security assessments. The list of adopted SCAS documents is maintained by the GSMA in FS.63 and continues to expand as 3GPP defines new network functions.
