Idle-Mode WTRU Paging Window Control for Power Saving
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in power consumption during idle mode, particularly in determining optimal paging occasions and monitoring for paging indicators, leading to unnecessary power usage by wireless transmit/receive units (WTRUs).
Innovation Solution
WTRUs determine a time window based on an offset from a paging occasion, monitor for cell-specific and WTRU-group specific paging indicators, and adjust monitoring behavior based on received indications to optimize power usage, including skipping unnecessary paging physical downlink control channel checks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If WTRUs monitor for paging indicators at every paging occasion, then paging reliability is improved, but power consumption increases
Solution Approach 1:
The paging indicator monitoring is segmented into two types: cell-specific PIs and WTRU-group specific PIs. WTRUs monitor cell-specific PIs at all paging occasions to maintain reliable paging reception, while monitoring for WTRU-group specific PIs selectively based on group assignments. This segmentation allows the system to maintain paging reliability through cell-specific monitoring while reducing overall power consumption by limiting WTRU-group specific monitoring to only when necessary.
2Reliability
If WTRUs monitor for both cell-specific and WTRU-group specific paging indicators, then paging coverage is improved, but device complexity increases
Solution Approach 1:
The monitoring behavior is made dynamic through DRX (Discontinuous Reception) cycles. WTRUs alternate between active monitoring periods and sleep periods based on configured DRX parameters. During active periods, WTRUs monitor for both cell-specific and WTRU-group specific PIs according to their group assignments; during sleep periods, monitoring is suspended. This dynamic approach maintains comprehensive paging coverage when needed while reducing device complexity and power consumption during inactive periods.
3Use of energy by moving object
If WTRUs skip monitoring for paging PDCCH after receiving wake up indication, then power saving is improved, but information loss increases
Solution Approach 1:
The system uses wake-up indications as a preliminary signal before full paging PDCCH monitoring. When a WTRU receives a wake-up indication, it knows that paging information will follow, allowing it to enter a low-power state temporarily. The WTRU then wakes up at the predetermined time to receive the actual paging message. This preliminary wake-up mechanism allows the WTRU to skip continuous monitoring while ensuring it doesn't miss the actual paging information, thus achieving power saving without information loss.
Data Source
AI summary
Systems, methods, and instrumentalities are described herein for wireless transmit/receive unit (WTRU) power saving (e.g., for idle mode). A WTRU may determine a time window associated with one or more paging indicators. The WTRU may monitor for a paging indicator (e.g., a first paging indicator) in the time window. The WTRU may monitor for another paging indicator (e.g., a second paging indicator) in the time window. The WTRU may receive system information blocks (SIBs) if a wake up indication for the WTRU is received in a single paging indication and the paging indicator is the first paging indicator. The WTRU may monitor for a paging PDCCH at a monitoring occasion of a PO in a paging frame if the second paging indicator is received and includes an indication for the WTRU to wake up.