5G NR PDCP entity establishment
When upper layers request a PDCP entity establishment for a radio bearer, the UE shall:
– establish a PDCP entity for the radio bearer;
– set the state variables of the PDCP entity to initial values;
– start data transfer
5G NR PDCP entity re-establishment
When upper layers request a PDCP entity re-establishment, the transmitting PDCP entity shall:
-> SRB: discard all stored PDCP SDUs and PDCP PDUs
-> UM DRB: for each PDCP SDU already associated with a PDCP SN but for which a corresponding PDU has not previously been submitted to lower layers, perform transmission of the PDCP SDUs in ascending order of the COUNT value associated to the PDCP SDU
-> AM DRB: Starting with the latest PDCP SDU that has nnot received ARQ feedback, perform and send all stored PDCP SDU in order of incresing SN.
When upper layers request a PDCP entity re-establishment, the receiving PDCP entity shall:
-> SRBs, discard all stored PDCP SDUs and PDCP PDUs;
-> UM DRBs, deliver all stored PDCP SDUs to the upper layers in ascending order of associated COUNT values after performing header decompression;
5G NR PDCP entity release
When upper layers request a PDCP entity release for a radio bearer, the UE shall:
–> discard all stored PDCP SDUs and PDCP PDUs in the transmitting PDCP entity;
->for UM DRBs and AM DRBs, deliver the PDCP SDUs stored in the receiving PDCP entity to upper layers in ascending order.
–> release the PDCP entity for the radio bearer.
5G NR PDCP entity suspend
When upper layers request a PDCP entity suspend, the transmitting PDCP entity shall:
– set TX_NEXT to the initial value;
– discard all stored PDCP PDUs;
When upper layers request a PDCP entity suspend, the receiving PDCP entity shall:
– if t-Reordering is running:
– stop and reset t-Reordering;
– deliver all stored PDCP SDUs to the upper layers in ascending order of associated COUNT values after performing header decompression;
– set RX_NEXT and RX_DELIV to the initial value.
Source TS 38 323