UE Power Saving via DRX and Wake-Up Signaling
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Solution Overview
Problem
User equipment (UE) in wireless communication systems faces challenges in power management due to the need to continuously monitor control channels, leading to increased power consumption and reduced battery life, especially when receiving control information outside of designated active times.
Innovation Solution
The UE receives a discontinuous reception (DRX) configuration from a base station and monitors the physical downlink control channel (PDCCH) for wake-up signals during designated inactive times, allowing it to skip monitoring periods and transition between sleep and active states based on specific DCI message formats, thereby optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE continuously monitors the PDCCH for control information, then the reliability of receiving control signaling is improved, but the power consumption increases
Solution Approach 1:
The patent implements discontinuous reception (DRX) where the UE alternates between active monitoring periods and sleep periods. During active time, the UE monitors PDCCH for control information; during non-active time, the UE skips monitoring to save power. This periodic action resolves the contradiction by making monitoring intermittent rather than continuous, reducing power consumption while maintaining reliability through scheduled monitoring occasions.
Solution Approach 2:
The network sends wake-up signals (WUS) before the UE's active time to indicate whether the UE should wake up for PDCCH monitoring. This preliminary action allows the UE to avoid unnecessary wake-ups and monitoring when there is no control information, thereby reducing power consumption while ensuring the UE is ready to receive control signaling when needed.
2Speed
If the UE monitors PDCCH outside of DRX active time, then the responsiveness to control information is improved, but the battery life is reduced
Solution Approach 1:
The patent introduces wake-up signals (WUS) as an intermediary mechanism between the network and the UE. The WUS is sent on PDCCH during non-active time to indicate whether the UE should wake up. This intermediary allows the network to control UE wake-ups efficiently, improving responsiveness when control information is present while minimizing unnecessary wake-ups to extend battery life.
Solution Approach 2:
The UE dynamically adjusts its monitoring behavior based on received WUS. When WUS indicates control information is pending, the UE wakes up to monitor PDCCH; when WUS indicates no control information, the UE remains in sleep mode. This dynamic adaptation resolves the contradiction by making the monitoring behavior flexible rather than fixed, balancing responsiveness and battery life.
3Use of energy by moving object
If the UE skips PDCCH monitoring during inactive times, then the power consumption is reduced, but the ability to receive control information promptly is worsened
Solution Approach 1:
The network performs preliminary action by sending wake-up signals before the UE's active time. These WUS indicate in advance whether the UE should wake up for PDCCH monitoring. This preliminary notification allows the UE to skip monitoring during inactive times (saving power) while still receiving control information promptly when needed, as the WUS prepares the UE for upcoming monitoring occasions.
Data Source
AI summary
Systems, devices, and techniques for user equipment (UE) power control are described. A described technique includes receiving, by a UE, a discontinuous receiving (DRX) configuration from a base station; monitoring, by the UE on a physical downlink control channel (PDCCH), for downlink control information (DCI) messages outside of a DRX active time, the DCI messages being of a predetermined format that is configured to provide wake-up signaling; receiving, by the UE, a DCI message outside of the DRX active time, the DCI message being of the predetermined format; and determining, by the UE, whether to wake-up based on the received DCI message.