5G • RAN
drx-RetransmissionTimerUL
DRX Uplink Retransmission Timer
Timer during which the UE remains awake to monitor PDCCH for an uplink HARQ retransmission grant.
Technical Explanation
After transmitting an uplink PUSCH, if the gNodeB requires a retransmission, the UE expects an uplink grant. After the uplink HARQ RTT timer expires, the UE starts drx-RetransmissionTimerUL and monitors PDCCH for DCI Format 0_0/0_1 carrying the New Data Indicator (NDI) requesting retransmission.
Key Functions
- Keeps receiver awake to monitor for pending uplink retransmission grants
- Synchronized with gNodeB asynchronous uplink HARQ processes
- Stops when new data grant or valid retransmission grant arrives
Specifications
3GPP TS 38.321
Interfaces
Uu
Related 5G Concepts
Want to memorize 5G concepts like this one?
Study it with SuperMemo SM-2 spaced repetition flashcards.