What is PDCP sequence number?

A PDCP layer sets a timer and discards a PDCP SDU upon expiration of the timer . The timer may be set upon receiving the PDCP SDU from an upper layer or upon submitting the PDCP SDU to a lower layer for transmission. The timer and a radio link control (RLC) discard timer may be coordinated.

PDCP is located in the Radio Protocol Stack in the UMTS/LTE/5G air interface on top of the RLC layer. PDCP provides its services to the RRC and user plane upper layers , e.g. IP at the UE or to the relay at the base station.

PDCP stands for Packet Data Convergence Protocol . It is a layer of 5G NR radio protocol stack. It is placed top of the RLC Layer and below of the SDAP layer(for user plane) or RRC layer (for control plane) in the Radio Protocol Stack in 5G NR. Due to header compression functionality, it is called as convergence …5 Oca 2022