3GPP 23.501 v20.2.0 — the document's own text
5.7.7.3 PDU Set Error Rate
Taught in 14. What the network promises (The 5G system architecture, in depth), 23. Very fast, very reliable, very picky (The 5G system architecture, in depth), 5. The connection, and what is promised on it (The 5G system architecture, overview).
The PDU Set Error Rate (PSER) defines an upper bound for the rate of PDU Sets that have been processed by the sender of a link layer protocol (e.g. RLC in RAN of a 3GPP access) but that are not successfully delivered by the corresponding receiver to the upper layer (e.g. PDCP in RAN of a 3GPP access). Thus, the PSER defines an upper bound for a rate of non-congestion related PDU Set losses. The purpose of the PSER is to allow for appropriate link layer protocol configurations (e.g. RLC and HARQ in RAN of a 3GPP access).
NOTE 1: In this Release, a PDU Set is considered as successfully delivered only when all PDUs of a PDU Set are delivered successfully.
NOTE 2: How 5G-AN enforces PSER is up to 5G-AN implementation.
A QoS Flow is associated with at most one PSER value per direction. PSER is an optional parameter. If the PSER is available, the UL and/or DL PSER supersedes the PER in the respective direction in the 5G-AN.
NOTE 3: See clause 5.7.7.1 for dependency between PDU Set QoS parameters.