Packet Data Convergence Protocol (PDCP)
PDCP protocol layer exists in UE & eNodeb, It is part of LTE air interface control and user planes.
The main services and functions of the PDCP sublayer for the user plane include:
- Header compression and decompression: ROHC only;
- Transfer of user data;
- In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM;
- Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM;
- Retransmission of PDCP SDUs at handover for RLC AM;
- Ciphering and deciphering;
- Timer-based SDU discard in uplink.
The main services and functions of the PDCP for the control plane include:
- Ciphering and Integrity Protection;
- Transfer of control plane data.
3GPP TS 36.323 - Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification