PDCP layer performs the following functions:
- Header compression and decompression plane of the user data;
- Security features:
encryption and deciphering the user plane and control plane data;
the protection of the integrity and operation of the plane data;
- Provide support functions:
order to delivery and reorder PDU to the layer above a waiver;
lossless transmission of user plane data associated with the RLC admitted mode.
- To cancel the user data plane due to timeout.
PDCP layer manages data streams in a plane, and in the plane (or Protocol), only for holders of a radio channel for control (DCCH) or channel dedicated to motion (DTCH). PDCP layer architecture varies the user plane and control plane, as shown figures.