Cell Selection Using Qrxlevmin-Offset to Prevent Ping-Pong Reselection
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Solution Overview
Problem
In current mobility management systems, terminals may experience ping-pong reselection between cells or fail to camp on a cell during reselection, and the effectiveness of handover decisions is poor due to reliance on frequency-specific minimum receiving level values without considering cell-specific offsets.
Innovation Solution
Introducing a pre-configured Cell specific minimum receiving level value Qrxlevmin-offset, which is considered in conjunction with the frequency-specific minimum receiving level value Qrxlevmin to determine the final target cell during cell selection and handover processes, ensuring accurate cell selection and improved reselection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only frequency-specific minimum receiving level value Qrxlevmin is used for cell selection, then the cell selection process is simple, but ping-pong reselection occurs between cells
Solution Approach 1:
The patent introduces a cell-specific offset parameter Qrxlevmin-offset that is locally configured for each cell, allowing different cells to have customized receiving level thresholds. This local differentiation prevents uniform treatment of all cells, thereby eliminating ping-pong reselection caused by identical frequency-specific thresholds while maintaining manageable complexity through standardized offset configuration mechanisms.
2Device complexity
If only signal level value is used for target cell determination, then the handover decision process is simple, but the effectiveness of cell selection is poor
Solution Approach 1:
The patent modifies the cell selection criterion by introducing an additional parameter Qrxlevmin-offset that adjusts the effective receiving level threshold. Instead of relying solely on signal level value comparisons, the system now evaluates whether signal level exceeds Qrxlevmin + Qrxlevmin-offset, thereby improving selection effectiveness through parameter enrichment while keeping the decision logic straightforward.
3Reliability
If Qrxlevmin of target cell is higher than frequency specific Qrxlevmin, then cell-specific requirements are met, but terminal makes ping-pong reselection between cells
Solution Approach 1:
The patent applies preliminary action by pre-configuring cell-specific offset values Qrxlevmin-offset in the network before terminal reselection operations. These offsets are broadcast to terminals in advance, allowing terminals to calculate accurate effective thresholds (Qrxlevmin + offset) before attempting cell camping, thereby avoiding repeated failed reselection attempts and reducing overall reselection time while ensuring cell-specific requirements are satisfied.
Data Source
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AI summary
The disclosure provides a mobility management method and device. The mobility management method includes: obtaining a frequency specific minimum receiving level value Qrxlevmin of each neighbor cell of a serving cell, a pre-configured Cell specific minimum receiving level value Qrxlevmin-offset of each neighbor cell, and a signal level value of each neighbor cell; calculating a sum value of the frequency specific minimum receiving level value Qrxlevmin and the Cell specific minimum receiving level value Qrxlevmin-offset of any neighbor cell; and taking a cell with a signal level value larger than the sum value of the frequency specific minimum receiving level value Qrxlevmin and the Cell specific minimum receiving level value Qrxlevmin-offset as a candidate target cell.