RRC State Change High Priority Cell Search Optimization
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Solution Overview
Problem
Conventional wireless networks face complexity and excessive battery consumption due to frequent high-priority cell searches, especially during state transitions, as existing algorithms require frequent measurements across multiple radio access technologies without clear timing for higher priority layer searches, leading to potential missed selections and increased power usage.
Innovation Solution
Modifying 3GPP specifications to allow high-priority searches only if the previous search was more than T higher_priority_search seconds ago, with T HPF2_SEARCH dependent on mobility and recent cell detection, reducing unnecessary measurements and maintaining battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-priority cell searches are performed frequently upon entering CELL_PCH, URA_PCH, or IDLE states, then reselection to higher priority layers is accelerated, but battery consumption increases excessively
Solution Approach 1:
The patent implements periodic high-priority cell searches at specific intervals (e.g., every 60 seconds or every T higher_priority_search seconds) rather than continuously or at every state transition. This periodic approach maintains timely reselection capability while significantly reducing overall search frequency and battery consumption compared to searching at every state change.
Solution Approach 2:
The patent performs high-priority cell searches during connected mode (CELL_DCH or CELL_FACH states) before transitioning to idle states. This preliminary action ensures that cell search information is already available when the device enters CELL_PCH, URA_PCH, or IDLE states, eliminating the need for immediate searches upon state transition and reducing overall search frequency.
2Measurement precision
If measurements are performed for all candidate cells across multiple radio access technologies, then reselection accuracy is improved, but algorithm complexity increases
Solution Approach 1:
The patent segments the cell measurement process into two distinct phases: high-priority cell searches during connected mode, and standard reselection evaluations in idle modes. This segmentation allows the device to focus computational resources on identifying high-priority cells first, then apply simpler evaluation criteria for final reselection decisions, reducing overall algorithmic complexity while maintaining accuracy.
Solution Approach 2:
The patent applies different measurement and evaluation criteria to different cell priority levels. High-priority cells receive dedicated searches with specific measurement parameters during connected mode, while lower-priority cells use standard reselection algorithms. This localized approach optimizes measurement precision for critical high-priority cells without requiring exhaustive measurements of all candidate cells, thereby reducing complexity.
Data Source
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AI summary
A user equipment is provided comprising: 1) transceiver circuitry configured to operate in cells associated with at least one radio access technology (RAT) network; and 2) a controller configured to perform neighbour cell searches. The controller is further configured to determine when the user equipment enters a first RRC state from a second RRC state. In response to the determination, the controller determines a time period since a most recent search of neighbour cells was performed. The first RRC state is one of at least: CELL_PCH, URA_PCH and IDLE. The second RRC state is one of at least CELL_FACH and CELL_DCH.