3GPP 38.300 v19.3.0 — the document's own text
4.10.3.1 Protocol Stack for NG User Plane
Taught in 4. What NR actually is, in the shape its own document gives it (TSG RAN — the group that specifies the radio, overview).
NG-U is defined as specified in clause 4.3.1.1 regardless of whether its transport is concentrated in the NR Femto GW. The figure below shows the NG-U protocol stack between NR Femto node and UPF.
