DRX Active State Management for 5G Beam Failure Recovery
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Solution Overview
Problem
In 5G systems, the existing discontinuous reception (DRX) mechanism fails to accurately receive certain messages, such as the slot format indicator (SFI), pre-emption indicator, beam recovery request response, and retransmission scheduling during grant-free transmission, leading to inefficiencies and increased power consumption.
Innovation Solution
A communication method that configures the communications device to send a beam failure recovery request using a physical uplink control channel (PUCCH) or media access control control element (MAC CE), determines an active state time for DRX based on the recovery request status, and adjusts timers to ensure accurate message reception and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the terminal device enters sleep state to reduce power consumption, then power consumption is reduced, but the device cannot receive certain messages such as beam failure recovery request response
Solution Approach 1:
The patent dynamically adjusts the DRX active state timing based on whether a beam failure recovery request is pending. When a beam failure recovery request is sent, the terminal device extends the active state to ensure the response window is covered, and transitions to sleep state only after the response window expires. This dynamic state adjustment resolves the contradiction by adapting the power saving mode to the actual communication needs.
Solution Approach 2:
The patent introduces a response window timer that is started before the expected arrival of the beam failure recovery request response. This preliminary action ensures the terminal device remains in active state and monitors the PDCCH during the critical response period, guaranteeing reliable message reception while minimizing the duration of the active state.
2Reliability
If the terminal device monitors PDCCH continuously to ensure accurate message reception, then message reception accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic monitoring of PDCCH within defined active states rather than continuous monitoring. The terminal device alternates between active states (when monitoring PDCCH) and sleep states (when not monitoring), creating a periodic pattern that reduces power consumption while maintaining the ability to receive critical messages during active periods.
Solution Approach 2:
The patent dynamically extends the active state duration based on the beam failure recovery request status. When such a request is pending, the active state is extended to cover the response window, ensuring accurate message reception only when necessary, rather than maintaining continuous active state for all message types.
3Reliability
If the DRX active state is extended to cover response window to ensure reliable reception, then message reception reliability is improved, but the duration of active state increases
Solution Approach 1:
The patent starts the response window timer in advance to define the exact period when the beam failure recovery request response is expected. This allows the terminal device to extend the active state precisely to cover only the necessary response window period, rather than extending it indefinitely, thus minimizing the active state duration while ensuring reliable reception.
Solution Approach 2:
The response window timer automatically controls the active state duration by expiring after a predetermined period. When the timer expires, the terminal device can transition to sleep state without requiring additional control signals or manual intervention, thereby limiting the active state duration to the minimum necessary for reliable message reception.
Data Source
AI summary
This application provides a communication method, a communications device, and a network device. When a beam failure occurs in a secondary cell of the communications device, the communications device sends a beam failure recovery request to the network device by using a PUCCH or a MAC CE, and determines an active state time of DRX based on a status of the beam failure recovery request. The communications device may also determine a stopping time of an uplink retransmission timer based on a running status of a configured grant timer, where the DRX of the communications device is in an active state when the uplink retransmission timer works; and monitors a PDCCH when the DRX of the communications device is in the active state.