Physical Layer Wake-Up Signal for PDCCH Monitoring Power Saving
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Solution Overview
Problem
In wireless mobile communication systems, particularly in 5G NR, the power consumption of User Equipment (UE) is high due to large bandwidth transmission and beam sweeping mechanisms, and existing power saving methods like Discontinuous Reception (DRX) are inefficient as they do not align well with dynamic data services, leading to unnecessary power consumption during monitoring of the physical downlink control channel (PDCCH).
Innovation Solution
A method and apparatus for a UE to perform power saving operations by receiving configuration information and monitoring a physical layer power saving signal, which includes a Wake Up Signal (WUS) or Go To Sleep Signal (GTSS), to determine whether to monitor a second PDCCH, thereby optimizing power usage by skipping unnecessary monitoring occasions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE monitors the PDCCH during every On-Duration of the DRX cycle, then the UE can detect data transmissions in timely manner, but the power consumption increases due to unnecessary monitoring when no data is transmitted
Solution Approach 1:
The base station performs preliminary action by transmitting a wake-up signal before the UE's On-Duration period. This wake-up signal indicates whether data transmission is scheduled, allowing the UE to determine in advance whether it needs to wake up for PDCCH monitoring, thus avoiding unnecessary power consumption while ensuring reliable data detection
2Reliability
If the drx-onDurationTimer or drx-InactivityTimer is configured with longer duration, then the UE can ensure continuous monitoring for data transmissions, but the power consumption increases and the alignment with dynamic data service deteriorates
Solution Approach 1:
The base station transmits wake-up signals in advance to indicate scheduled data transmissions, allowing the UE to adjust its monitoring duration dynamically based on actual data service needs rather than relying on fixed long-duration timers, thus reducing power consumption while maintaining monitoring reliability
3Use of energy by moving object
If the base station transmits a DRX command MAC CE to indicate the UE to enter Opportunity-for-DRX in advance, then the UE can stop monitoring earlier to save power, but the MAC layer signaling introduces time delay
Solution Approach 1:
The patent replaces the MAC layer signaling mechanism with a physical layer wake-up signal mechanism. This substitution eliminates the processing and transmission delays associated with MAC CE signaling, allowing the UE to quickly determine whether to enter Opportunity-for-DRX without the time delay introduced by higher layer protocol processing
4Reliability
If the UE wakes up at every paging occasion to monitor the PDCCH, then the UE can detect paging messages, but the power consumption increases due to monitoring occasions without paging messages
Solution Approach 1:
The base station transmits wake-up signals before paging occasions to indicate whether paging messages will be transmitted. The UE monitors these wake-up signals and only wakes up for full PDCCH monitoring when indicated by the wake-up signal, thus detecting paging messages reliably while avoiding power consumption during occasions without paging messages
Data Source
AI summary
Embodiments of the disclosure provides a method and an apparatus for power saving operation in a wireless communication system, wherein the method comprises: receiving configuration information for the power saving operation; monitoring a power saving signal based on the configuration information; and determining whether to monitor a PDCCH based on the power saving signal.