Sintersearch Beacon for Cell Reselection Control
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Solution Overview
Problem
UMTS Femtocells face challenges in cell reselection from macro-cells to smaller cells, such as femtocells, due to restrictive cell reselection criteria, leading to suboptimal load balancing and increased battery consumption in user equipment (UEs), with existing solutions either increasing power consumption or causing interference with macro-cell signals.
Innovation Solution
A method involving dynamically toggling cell reselection thresholds, specifically the Sintersearch threshold, to periodically prompt UEs to search for better cells, even when under good coverage, using a 'Sintersearch beacon' mechanism that adjusts the threshold between normal and maximum values, minimizing battery usage and avoiding interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cell reselection criteria are made more restrictive to improve macro-cell coverage stability, then macro-cell service reliability is improved, but UE battery consumption increases and load balancing deteriorates
Solution Approach 1:
The patent applies periodic action by implementing a timer mechanism that periodically adjusts the Sintersearch threshold between normal and high values. The network switches the threshold to high value for limited durations (e.g., 5 seconds) to prompt UE reselection, then returns to normal value to maintain stable connections. This periodic toggling balances macro-cell reliability with UE battery consumption by limiting the duration of energy-intensive search operations.
Solution Approach 2:
The patent implements dynamics by making the Sintersearch threshold adjustable rather than fixed. The network dynamically switches the threshold between normal and high values based on load conditions and UE behavior. This dynamic adjustment allows the system to adapt to changing network conditions, promoting load balancing while minimizing unnecessary UE battery consumption compared to static restrictive criteria.
2Reliability
If cell reselection criteria are made more restrictive to maintain macro-cell coverage, then macro-cell service quality is improved, but load balancing between macro and femto cells deteriorates
Solution Approach 1:
The network periodically switches the Sintersearch threshold to high value for limited durations to prompt UE reselection toward femto cells, then returns to normal value to maintain stable macro-cell connections. This periodic adjustment enables load balancing without permanently changing the restrictive criteria that ensure macro-cell service quality.
Solution Approach 2:
The network performs preliminary action by proactively adjusting the Sintersearch threshold before UE reselection becomes necessary. By switching to high threshold values in advance during idle periods, the network prepares for load balancing opportunities while maintaining the option to revert to normal thresholds to preserve macro-cell service quality when needed.
3Productivity
If the Sintersearch threshold is continuously set to high value to enable frequent cell searches, then UE reselection to smaller cells is improved, but UE battery consumption increases significantly
Solution Approach 1:
The patent implements periodic action by limiting high Sintersearch threshold durations to specific time windows (e.g., 5 seconds) rather than maintaining them continuously. The network switches the threshold to high value only during these brief periods to prompt reselection, then returns to normal values, significantly reducing UE battery consumption while maintaining reselection efficiency.
Solution Approach 2:
The patent applies partial action by implementing high threshold values only for limited durations rather than continuously. This partial application of the high threshold achieves sufficient reselection promotion without the excessive battery consumption that would result from continuous high threshold operation.
4Productivity
If RF jamming is used to force UE reselection to femtocells, then load balancing is improved, but macro-cell capacity is degraded and interference is caused
Solution Approach 1:
The patent changes the parameter Sintersearch threshold between normal and high values to control UE reselection behavior without causing interference. This parameter adjustment approach achieves load balancing by influencing UE decision-making algorithms, avoiding the harmful interference and macro-cell capacity degradation associated with RF jamming.
Solution Approach 2:
The patent substitutes the mechanical/physical RF jamming approach with a protocol-level parameter adjustment mechanism. Instead of using electromagnetic interference to force reselection, the network modifies the Sintersearch threshold parameter in the cell reselection criteria, achieving the same load balancing effect through software-based control rather than physical interference.
Data Source
AI summary
A method for cell reselection control is disclosed, comprising: sending an instruction from a radio network to a user equipment (UE) in an idle mode to adjust an existing cell reselection parameter at a UE to a high value; subsequently instructing the UE to return the cell reselection parameter to its previous value, after a first predetermined interval; and subsequently sending a second instruction to the UE in an idle mode to adjust the cell reselection parameter at the UE to the high value, after a second predetermined periodic interval, causing the UE to reselect to a cell with superior signal even when the UE may be under good coverage attached to an existing macro cell, thereby offloading the macro cell.