5G-NR tutorials and call flows

The flows below are sequence diagrams of the standardized 5G-NR procedures. To see the same signaling in a live trace, VisualEther turns a Wireshark 5G-NR capture into a sequence diagram like these — then lets Claude Code explain why a registration or PDU-session attempt failed, down to the frame.

Call flows

5G-NR Non Standalone Access Flow (EN-DC)

LTE support for 5G dual connectivity will enable 4G network operators to introduce 5G services with a minimal upgrade to support 5G data plane. This is achieved with the support for 4G eNB and 5G gNB dual connectivity (EN-DC).

5G-NR Standalone Access Registration Flow

As 5G gains momentum, the networks will transition to an end-to-end 5G solution with UEs registering with the 5G Core Network. The 5G standalone access registration signaling flow is similar to the 4G attach and default bearer establishment flow.

Medium blog posts

5G NR: The New Radio interface for 5G

The 5G air interface that scales from cellular to the mm-wave bands.

5G physical layer specifications

The 5G specifications have been published as the 3GPP 38 series. Here we look at the physical layer specifications.

Massive MIMO

MIMO with large phased array antenna array at the base station

LDPC — low density parity check code

5G AN uses LDPC for channel coding on the traffic channel. LDPC corrects channel errors by maintaining parity bits for a selection of the data bits.

Cloud RAN and eCPRI fronthaul in 5G networks

5G networks will move towards centralizing the radio function using an eCPRI based fronthaul.

Mobility with mm-waves

5G specifications are extending the reach of mobile communication by supporting frequency bands up to 100 GHz.

5G non-standalone access

Signaling flow for 5G access via LTE-5G NR dual connectivity (EN-DC).

5G Service-Based Architecture (SBA)

Learn now the 5G Core Network has been designed around services that are invoked using a standard API.

5G Standalone Access Registration

Signaling flow for 5G standalone access registration.

5G NR RLC Acknowledged Mode

Deep dive into the 5G Radio Link Control in Acknowledged Mode.