Base Station Selection Using UL Quality Thresholds
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Solution Overview
Problem
In mobile communication systems, the Radio Network Controller (RNC) cannot accurately determine DownLink (DL) quality values for User Equipment (UE) when UpLink (UL) quality values are low, leading to inadequate resource allocation and poor data service quality.
Innovation Solution
A method and apparatus that periodically monitor both DL and UL quality values, setting a minimum UL quality value threshold, and select the Base Station (BS) with the maximum DL quality value among those with UL quality values equal to or greater than this threshold as the new serving BS, ensuring stable data service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the RNC allocates resources based solely on DL quality values reported by UE, then resource allocation efficiency is improved, but service reliability deteriorates when UL quality is low causing inaccurate DL quality reporting
Solution Approach 1:
The patent implements a feedback mechanism where the RNC monitors UL quality values and uses them to validate the reliability of DL quality reports from UE. When UL quality falls below a threshold, the RNC identifies that DL quality reports may be inaccurate and adjusts resource allocation accordingly, preventing wasted resources on unreliable connections while maintaining efficient allocation for reliable connections.
Solution Approach 2:
The patent changes the resource allocation parameters dynamically based on UL quality conditions. When UL quality is above the threshold, the system uses DL quality values for resource allocation. When UL quality drops below the threshold, the system adjusts resource allocation to account for potential DL quality reporting inaccuracies, effectively changing the allocation strategy based on the reliability indicator (UL quality).
2Manufacturing precision
If the RNC assigns more resources to UE with higher DL quality values, then data service quality is improved, but system fairness deteriorates when UL quality constraints are ignored
Solution Approach 1:
The patent introduces a conditional parameter change mechanism where the resource allocation decision depends on both DL quality and UL quality parameters. The system adjusts the effective DL quality metric used for resource allocation based on whether UL quality meets the threshold, ensuring that high resource allocation is only granted when both DL and UL conditions support high-quality service.
Solution Approach 2:
The UL quality threshold acts as an intermediary condition that mediates between DL quality measurements and final resource allocation decisions. This intermediary check ensures that DL quality reports are only trusted for resource allocation when UL quality conditions permit, preventing unfair resource distribution to UEs with poor uplink conditions that cannot reliably report downlink quality.
3Stability of the object's composition
If the RNC determines serving BS based only on DL quality, then connection stability is improved, but measurement accuracy deteriorates when UL quality is insufficient for reliable DL quality reception
Solution Approach 1:
The patent uses UL quality as a feedback indicator to assess the reliability of DL quality measurements. When UL quality is below the threshold, the RNC infers that DL quality reports may be inaccurate and adjusts its serving BS selection criteria accordingly, potentially requiring higher DL quality margins or more frequent re-evaluation to maintain connection stability despite measurement uncertainties.
Solution Approach 2:
The system applies a cushioning effect by requiring an additional quality margin when UL quality is poor. This beforehand cushioning compensates for potential measurement inaccuracies in DL quality reports by raising the effective threshold for BS selection, ensuring that connection stability is maintained even when measurement precision is compromised by poor UL conditions.
Data Source
AI summary
A method of changing a serving Base Station (BS) in a mobile communication system, and a mobile communication system for implementing the method, are provided. The method includes setting a minimum UpLink (UL) quality value, receiving DownLink (DL) quality values for a current serving BS of a User Equipment (UE) and respective BSs included in an active set of the UE from the UE periodically based on a predefined first period, receiving UL quality values for the serving BS and the respective BSs included in the active set from the serving BS and the respective BSs included in the active set periodically based on a predefined second period, determining if the UL quality value for the serving BS is less than the minimum UL quality value, when, as a result of the determination, the UL quality value for the serving BS is less than the minimum UL quality value, selecting BSs, which have UL quality values equal to or greater than the minimum UL quality value among the BSs included in the active set, as candidate BSs, and determining a BS, which has a maximum DL quality value among the candidate BSs, as a new serving BS of the UE, wherein the active set represents a set of BSs that can provide DL/UL service to the UE.