The main services provided by the Packet Data Convergence Protocol (PDCP) are:
There is more function of PDCP in LTE is as below
PDCP in LTE for sublayer of user plane function:
- For Handover RLC AM Retransmission of PDCP SDUs
- For ROHC – Header compression and decompression
- user data Transfer
- In PDCP re-establishment procedure for RLC AM for In-sequence delivery on upper layer PDUs.
- PDCP re-establishment procedure for RLC AM for duplicate detection of lower layer SDUs
- PDCP in LTE use for ciphering and deciphering
- In uplink SDU discard based on timer.
PDCP in LTE for the control plane Function:-
- PDCP in LTE use Integrity Protection and Ciphering.
- Data Transfer of control plane.
The header of an IP packet is 20 octets.
For example, during an FTP transfer, a lot of IP packets are sent over the air interface and the IP headers are almost always the same.
They represent a significant amount of data which can be reduced thanks to a compression method.
The PDCP header is 1 (or 2) octet. The Robust Header Compression (ROHC) is a standardized method used to compress IP, UDP, TCP and RTP headers.