Sidelink DRX Alignment with Uu-DRX for Power Savings
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing discontinuous reception (DRX) configurations for user equipment (UE) in both Uu and sidelink (SL) interfaces, leading to potential power savings and latency issues due to misalignment of DRX cycles between Uu and SL, especially in scenarios like Vehicle-to-Vehicle (V2V) communications.
Innovation Solution
Implementing enhanced DRX management techniques, including gNB-triggered SL-DRX based on Uu MAC control element signaling, UE-assisted DRX configuration messaging, and alignment of SL-DRX with Uu-DRX cycles, allowing for power savings and reduced latency by coordinating DRX operations across both interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate DRX configurations are used for Uu and SL interfaces, then each interface can be optimized independently, but power consumption increases and latency is elevated due to misalignment
Solution Approach 1:
The patent merges Uu-DRX and SL-DRX configurations by having the gNB provide a single Uu-DRX configuration that is applied to both Uu and SL interfaces. This unification ensures that DRX cycles are aligned across both interfaces, preventing the power consumption increase that would result from managing separate, potentially misaligned DRX configurations independently.
2Adaptability or versatility
If separate DRX configurations are used for Uu and SL interfaces, then each interface can be optimized independently, but end-to-end latency increases due to misalignment
Solution Approach 1:
The patent combines the DRX configuration management for Uu and SL interfaces into a unified approach where a single Uu-DRX configuration is provided by the gNB and applied to both interfaces. This ensures synchronized DRX cycles, eliminating the latency penalties that arise from misaligned DRX operations across separate interfaces.
Solution Approach 2:
The gNB proactively provides the Uu-DRX configuration to the UE before DRX operations begin, ensuring that both Uu and SL interfaces are pre-configured with aligned DRX parameters. This preliminary configuration action prevents subsequent latency issues that would result from dynamic, uncoordinated DRX adjustments.
3Use of energy by moving object
If aligned DRX configurations are enforced for Uu and SL interfaces, then power savings and latency are improved, but device complexity increases due to coordinated management
Solution Approach 1:
The UE automatically applies the Uu-DRX configuration provided by the gNB to both Uu and SL interfaces without requiring complex coordination mechanisms. This self-service approach allows the UE to independently manage aligned DRX operations, achieving power savings while avoiding the device complexity that would result from sophisticated inter-interface coordination protocols.
4Loss of time
If aligned DRX configurations are enforced for Uu and SL interfaces, then buffering requirements are minimized, but device complexity increases due to coordinated management
Solution Approach 1:
The patent merges the DRX configuration management into a unified system where a single Uu-DRX configuration controls both Uu and SL interfaces. This unification ensures that data buffering requirements are minimized due to synchronized DRX cycles, while avoiding the device complexity that would arise from managing separate coordination mechanisms for each interface.
Data Source
AI summary
SL-DRX involves both Uu and PC5 interfaces. For an RRC_CONNECTED UE (also referred to as a connected mode UE, or simply connected UE), several SL-DRX enhancements are described in this disclosure to trigger SL DRX and share configurations. Alignment of SL-DRX alignment with Uu-DRX (referred to as Uu/SL DRX alignment or simply alignment) is also described, as an optional feature (since not all schedules can temporally align).