5G • RAN
PDCP
Packet Data Convergence Protocol
The 5G radio protocol layer responsible for IP header compression (ROHC), ciphering, integrity protection, and dual-connectivity packet duplication.
Technical Explanation
PDCP is situated in Layer 2 of the 5G radio interface between SDAP and RLC (hosted in the CU in split RAN). It performs Robust Header Compression (ROHC) and Uplink Data Compression (UDC), user plane and control plane ciphering/integrity protection using 128-bit or 256-bit keys (NEA/NIA algorithms), sequence numbering, in-order delivery, reordering, and duplicate detection. In Dual Connectivity (EN-DC / NR-DC), PDCP splits or duplicates traffic across multiple carriers.
Key Functions
- Robust Header Compression (ROHC) to minimize packet overhead
- Ciphering and Integrity Protection for user plane and control plane data
- Packet duplication for ultra-high reliability in URLLC
- In-order delivery and reordering during handovers
Specifications
3GPP TS 38.323
Interfaces
Uu Radio Protocol Stack (CU hosted)
Related 5G Concepts
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