5G • RAN
RLC UM
Radio Link Control Unacknowledged Mode
RLC mode providing segmentation, reassembly, and sequence numbering without ARQ retransmissions.
Technical Explanation
Unacknowledged Mode (UM) adds sequence numbers (6-bit or 12-bit) to enable segmentation, reassembly, and duplicate detection, but does not perform ARQ retransmissions. It is ideal for delay-sensitive, loss-tolerant real-time traffic such as VoNR voice (conversational audio) and video streaming.
Key Functions
- Provides segmentation and reassembly of SDUs into PDUs
- Detects duplicates and reorders packets using sequence numbers
- Omits ARQ retransmissions to maintain minimal latency for voice and video
Specifications
3GPP TS 38.322
Interfaces
Uu
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