5G Reference: Architecture, Protocols, Call Flows & Messages

5G is the 3GPP-defined mobile system for 5G NR and 5G Core networks. This page organizes 5G architecture, interfaces, protocols, call flows, messages, troubleshooting, tools, and releases in one structured reference for engineers, testers, and learners.

5G Architecture

Understand the 5G network structure, including NG-RAN, 5GC, SBA, core functions, and radio access architecture.

View all 5G architecture

5G Interfaces

Explore the main 5G interfaces across the UE, NG-RAN, 5GC, split RAN, and service-based architecture.

View all 5G interfaces

5G Protocols

Browse the 5G protocol stack across PHY, MAC, RLC, SDAP, PDCP, RRC, NAS, NGAP, and related signalling layers.

View all 5G protocols

5G Messages

Browse searchable 5G protocol message libraries for RRC, NAS, NGAP, F1AP, E1AP, XnAP, and IMS SIP signalling.

View all 5G messages

5G Call Flows

Study end-to-end 5G signalling procedures for access, registration, security, PDU sessions, mobility, handover, and voice.

View all 5G call flows

5G Troubleshooting

Use symptom-led and protocol-led guides to debug registration, access, RRC, PDU session, mobility, throughput, and handover problems.

View all 5G troubleshooting

5G Tools

Access calculators and utilities for radio planning, throughput checks, frequency mapping, and protocol decoding.

View all tools

5G Releases

Track 5G standards evolution and 5G-Advanced features through release-oriented reading paths.

View all releases

FAQ

Quick answers for common 5G reference questions.

What is covered in the 5G reference section?

The 5G reference section covers architecture, interfaces, protocols, call flows, messages, troubleshooting, tools, and release-level features for 5G NR and 5G Core networks.

Where can I find 5G protocol messages?

Use the 5G Messages hub to browse RRC, NAS, NGAP, F1AP, E1AP, XnAP, and IMS SIP message libraries.

Where can I learn 5G architecture?

Start with the 5G Architecture section for NG-RAN, 5GC, SBA, gNB, AMF, SMF, UPF, and VoNR architecture pages.

Where can I troubleshoot 5G registration or access failures?

Use the 5G Troubleshooting section for registration, access, RRC, NAS, AMF selection, TAI mismatch, and emergency registration issues.

What tools are useful for 5G engineers?

Useful tools include NR ARFCN, GSCN, throughput, link budget, TBS, and 3GPP decoder tools.

Which 5G interfaces are covered?

The site covers N1, N2, N3, N4, N6, N9, NG, Xn, F1, E1, and service-based interfaces.

References

Core reference areas behind the 5G library.

  • 3GPP 5G NR and 5G Core protocol specifications
  • 5G architecture, interfaces, signalling procedures, and troubleshooting references
  • 5G-Advanced release notes and practical engineering tools