3GPP 23.501 v20.2.0 — the document's own text

5.33.1 General

Taught in 23. Very fast, very reliable, very picky (The 5G system architecture, in depth).

The following features described in 5.33 may be used to enhance 5GS to support Ultra Reliable Low Latency Communication (URLLC):

Redundant transmission for high reliability communication.

In this Release, URLLC applies to 3GPP access only.

When a PDU Session is to serve URLLC QoS Flow, the UE and SMF should establish the PDU Session as always-on PDU Session as described in clause 5.6.13.

NOTE 1: How the UE knows whether a PDU Session is to serve a URLLC QoS Flow when triggering PDU Session establishment is up to UE implementation.

NOTE 2: No additional functionality is specified for URLLC in order to support Home Routed roaming scenario in this Release.