5G • RAN
PDCP SN
PDCP Sequence Number
12-bit or 18-bit sequence number added to user plane data packets for ciphering, integrity, and reordering.
Technical Explanation
5G NR PDCP supports 12-bit and 18-bit sequence numbers for User Plane Data Radio Bearers (DRBs) and 12-bit for Signaling Radio Bearers (SRBs). The PDCP SN forms the lower bits of the 32-bit COUNT parameter used by AES and ZUC encryption algorithms, and enables lossless in-order packet delivery during mobility handovers.
Key Functions
- Forms lower-order bits of 32-bit COUNT value for security encryption
- Supports 12-bit and 18-bit lengths for multi-gigabit throughput
- Enables in-order packet reordering and lossless handover buffering
Specifications
3GPP TS 38.323
Interfaces
Uu
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