Sidelink DRX Configuration for Power Saving in Wireless Systems
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Solution Overview
Problem
Current NR sidelink technologies in Rel-16 are not optimized for power saving, especially for vulnerable road users and public safety scenarios, and face limitations in achieving high reliability and low latency due to assumptions of 'always-on' operations, which are not feasible for all user equipment (UEs).
Innovation Solution
The method involves configuring sidelink discontinuous reception (DRX) for User Equipment (UE) to optimize power consumption by aligning sidelink DRX wake-up times with Uu DRX wake-up times, using predefined DRX patterns that consider traffic patterns and service types, and integrating these configurations into the network control to ensure efficient power management and reliable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sidelink communication operates in 'always-on' mode to ensure high reliability and low latency, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements discontinuous reception (DRX) cycles with periodic on-durations and off-durations, allowing UEs to alternate between active listening and sleep states. During on-duration, UEs monitor sidelink channels for communications; during off-duration, UEs enter sleep mode to conserve power. This periodic operation enables vulnerable road user UEs to achieve power saving while maintaining reliable communication through scheduled wake-up periods.
Solution Approach 2:
The patent establishes synchronization mechanisms where UEs align their DRX wake-up times in advance based on predetermined parameters such as group ID, destination layer 2 ID, and offset values. By pre-coordinating wake-up schedules before actual communication occurs, the system ensures that UEs are awake and ready to receive critical safety messages at the appropriate times, maintaining low latency and high reliability without requiring continuous operation.
2Use of energy by moving object
If sidelink DRX wake-up times are aligned with Uu DRX wake-up times to optimize power saving, then power consumption is reduced, but coordination complexity increases
Solution Approach 1:
The patent applies the same DRX configuration parameters and synchronization mechanisms across both sidelink and Uu interfaces. By using universal DRX parameters (such as drx-OnDuration, drx-SlotOffset, and wake-up time calculations) for both interfaces, the system enables UEs to synchronize wake-up times without requiring separate complex coordination protocols. This multi-functional approach reduces power consumption through unified sleep scheduling while minimizing coordination complexity by reusing existing DRX framework.
3Use of energy by moving object
If discontinuous reception is implemented for vulnerable road user UEs to save power, then power saving is improved, but latency may increase due to sleep periods
Solution Approach 1:
The patent implements dynamic DRX configuration where on-duration lengths, off-duration lengths, and wake-up time offsets are adjustable based on communication requirements. For time-critical safety communications, the system can dynamically shorten off-durations or increase on-duration frequencies, ensuring that vulnerable road user UEs wake up more frequently to reduce latency. Conversely, for less time-sensitive traffic, longer sleep periods can be configured to maximize power saving. This dynamic adaptation allows the system to optimize the trade-off between power saving and latency based on real-time communication needs.
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AI summary
A method and device are disclosed for a User Equipment, UE, to configure sidelink discontinuous reception, DRX, for sidelink groupcast communication associated with a group are disclosed. In one embodiment, the method includes the UE applying a sidelink DRX configuration for the sidelink groupcast communication associated with the group, wherein the sidelink DRX configuration comprises at least one of an on-duration timer length used for determining an on-duration for each sidelink DRX cycle and/or a cycle length used for determining a length of each sidelink DRX cycle (1305). The method further includes the UE deriving or determining a time to start of on-duration for each sidelink DRX cycle or start of each sidelink DRX cycle based on at least an identifier associated with the group (1310). The method also includes the UE monitoring a sidelink control channel, associated with the group, based on the sidelink DRX configuration and the time to start of on-duration for each sidelink DRX cycle or start of each sidelink DRX cycle (1315).