3GPP 38.300 v19.3.0 — the document's own text
5.7.2 Sidelink resource allocation modes/schemes
Taught in 2. The six working groups and the line between them (TSG RAN — the group that specifies the radio, overview), 2. The six groups, and what each one worries about (TSG RAN — the group that specifies the radio, quick start).
Two sidelink resource allocation modes are supported for sidelink communication: mode 1 and mode 2. Two sidelink resource allocation schemes are supported for SL-PRS transmission: scheme 1 and scheme 2. In mode 1/scheme 1, the sidelink resource allocation is provided by the network. In mode 2/scheme 2, UE decides the SL transmission resources in the resource pool(s).