XR UE Power Saving via Dynamic C-DRX and Wake-Up Signals
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Solution Overview
Problem
Current C-DRX methods are inefficient for XR devices in 5G NR due to non-integer and quasi-periodic traffic patterns, leading to misalignment of wake-up times and excessive power consumption, as they require frequent wake-ups to monitor PDCCH and cannot effectively employ deep or light sleep modes for power savings.
Innovation Solution
An XR-specific C-DRX method and system that selectively controls the periodic sleeping and waking state of XR devices by skipping unnecessary wake-up signals (WUS) and employing configurable sleep modes based on sleep duration, using a control unit with a radio resource control (RRC) module to manage media access and enable XR devices to choose the best sleep mode for maximizing power savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If C-DRX method is used with short cycle to meet low latency requirements, then latency is reduced, but power consumption increases
Solution Approach 1:
The patent implements dynamic C-DRX cycle adjustment where the system transitions from short C-DRX cycles during initial connection and data transmission to longer C-DRX cycles during idle periods. The gNB configures different drx-LongCycle values based on traffic conditions, allowing the UE to extend sleep duration when no data is being transmitted, thus reducing power consumption while maintaining low latency when needed.
Solution Approach 2:
The patent utilizes periodic WUS (Wake-Up Signal) messages sent by the gNB to the UE at configured intervals. The UE monitors PDCCH only during these periodic wake-up opportunities indicated by WUS messages, rather than continuously. This periodic monitoring mechanism allows the UE to enter deep sleep modes between WUS occasions, significantly reducing power consumption while ensuring timely data reception when traffic arrives.
2Reliability
If UE wakes up frequently to monitor PDCCH, then data transmission reliability is improved, but power consumption increases
Solution Approach 1:
The patent introduces WUS (Wake-Up Signal) as an intermediary mechanism between the gNB and UE. Before the UE needs to monitor PDCCH for downlink data, the gNB sends a WUS message to notify the UE of upcoming data transmission. This intermediary signal allows the UE to remain in sleep mode and only activate PDCCH monitoring when actually needed, ensuring data transmission reliability while minimizing unnecessary wake-ups and power consumption.
Solution Approach 2:
The patent implements preliminary notification through WUS messages that are sent before the actual data transmission occurs. The gNB configures WUS parameters (timeOffset, periodicity) to notify the UE in advance of upcoming data transmissions. This allows the UE to prepare for PDCCH monitoring only when necessary, rather than continuously monitoring, thus maintaining reliability while reducing power consumption during idle periods.
3Use of energy by moving object
If C-DRX cycle is extended for power saving, then power consumption is reduced, but latency increases
Solution Approach 1:
The patent implements dynamic C-DRX cycle adjustment where the system transitions from short C-DRX cycles during initial connection and data transmission to longer C-DRX cycles during idle periods. The gNB configures different drx-LongCycle values based on traffic conditions, allowing the UE to extend sleep duration when no data is being transmitted, thus reducing power consumption while maintaining low latency when needed.
4Reliability
If UE monitors PDCCH continuously, then data transmission reliability is improved, but power consumption increases
Solution Approach 1:
The patent utilizes periodic WUS (Wake-Up Signal) messages sent by the gNB to the UE at configured intervals. The UE monitors PDCCH only during these periodic wake-up opportunities indicated by WUS messages, rather than continuously. This periodic monitoring mechanism allows the UE to enter deep sleep modes between WUS occasions, significantly reducing power consumption while ensuring timely data reception when traffic arrives.
Data Source
AI summary
The present invention discloses a system for controlling periodical switching of XR devices or components thereof of an UE in 5G NR communication comprising a control unit for said 5G NR communication involving a gNB and said UE, wherein the control unit further includes a resource control module (RRC) for the UE which communicates with RRC of the gNB facilitating the UE to change its media access control and a XR-specific C-DRX module for XR-specific enhancement including enabling the XR devices or components thereof to select best possible sleep mode from different sleep modes as a function of sleep duration for maximizing UE power savings.