5G • RAN

C-DRX

Connected Mode Discontinuous Reception

Power saving protocol allowing UEs in RRC_CONNECTED to power down receiver circuitry according to a synchronized cycle.

Technical Explanation

Connected Mode DRX allows the UE to sleep periodically during connected state when no data is being exchanged. The UE awakens only during configured 'On-Duration' windows to check for PDCCH grants. If data is scheduled, inactivity timers keep the receiver awake; otherwise, the UE returns to sleep, saving up to 80% receiver energy.

Key Functions

  • Allows radio transceiver sleep in RRC_CONNECTED state
  • Synchronizes awake periods between gNodeB scheduler and UE
  • Dramatically reduces device battery consumption during active sessions
Specifications
3GPP TS 38.321
Interfaces
Uu

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