5G • RAN
drx-RetransmissionTimerDL
DRX Downlink Retransmission Timer
Timer during which the UE remains awake to monitor PDCCH for downlink HARQ retransmission assignments.
Technical Explanation
When a downlink PDSCH fails CRC and the UE sends a NACK, it starts drx-HARQ-RTT-TimerDL. When that RTT timer expires, the UE starts drx-RetransmissionTimerDL and keeps its receiver active to receive the expected HARQ retransmission from the gNodeB.
Key Functions
- Maintains receiver awake state awaiting expected downlink retransmissions
- Started immediately upon expiry of drx-HARQ-RTT-TimerDL
- Stopped once the expected retransmission is successfully decoded
Specifications
3GPP TS 38.321
Interfaces
Uu
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