LTE Paging Cycle Enhancement for Power Saving
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Solution Overview
Problem
LTE devices face challenges with power efficiency due to short paging cycles, which affect battery life, network signaling, and mobility, especially with long sleep cycles leading to inaccurate cell reselection and paging robustness issues.
Innovation Solution
The implementation of an enhanced cell reselection procedure and paging mechanism, including extended cell reselection parameters and absolute time paging, allows UEs to perform cell reselection and wake up for paging based on valid parameters over a wider area, reducing power consumption and improving robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the paging cycle is extended to reduce power consumption, then battery life is improved, but paging robustness and mobility performance deteriorate
Solution Approach 1:
The patent implements a periodic wake-up mechanism where the UE wakes up at specific intervals (paging occasions) to monitor the paging channel. This periodic action allows the UE to maintain long sleep cycles for power saving while ensuring it checks for paging messages at regular intervals, thus maintaining paging robustness despite the extended cycle length.
Solution Approach 2:
The patent introduces a wake-up signal mechanism that allows the network to preliminarily notify the UE before actual paging occurs. The UE can wake up early to check for wake-up signals, and only fully activate if needed. This preliminary action reduces unnecessary full wake-ups while maintaining paging reliability.
2Use of energy by moving object
If the paging cycle is extended to save power, then battery life is improved, but mobility measurement accuracy deteriorates
Solution Approach 1:
The patent maintains periodic wake-up occasions even during long DRX cycles, allowing the UE to perform mobility measurements at these regular intervals. This periodic measurement approach ensures mobility accuracy is maintained without requiring continuous monitoring, thus preserving power efficiency.
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports mobility measurement results to the network at wake-up occasions. The network uses this feedback to make informed handover decisions, compensating for the reduced measurement frequency caused by long sleep cycles.
3Use of energy by moving object
If the paging cycle is extended beyond SFN wrap-around limit, then power saving is improved, but current paging calculation method becomes invalid
Solution Approach 1:
The patent modifies the paging occasion calculation parameters to work with extended DRX cycles beyond the traditional SFN wrap-around limit. By changing the calculation methodology to accommodate longer cycles, the system enables extended power saving while maintaining functional paging operation.
Solution Approach 2:
The patent introduces dynamic adjustment of paging parameters based on the extended cycle length. The system adaptively adjusts paging occasion timing and parameters to match the extended DRX cycle, allowing flexible operation beyond fixed SFN limitations while managing calculation complexity.
Data Source
AI summary
An enhanced paging mechanism is provided for UEs waking up from a very long paging cycle to improve paging robustness and flexibility. Enhanced paging includes absolute time paging (ATP) and paging with extended wakeup time. For absolute time paging, a UE receives ATP configuration and uses the actual wall time to calculate paging occasion if a condition is satisfied. In one embodiment, the wall time is acquired from at least one of an internal UE clock, a GPS time, information broadcasted from the network, or information from a higher layer signaling. For paging with extended wakeup time, a UE applies a long paging cycle followed by multiple normal paging cycles after waking up from the long paging cycle. In one embodiment, the long paging cycle is infinite and the UE enters normal paging cycle only upon TAU-triggered paging or uplink traffic.