LTE-Advanced Cell Selection Criteria for Terminal Distribution
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Solution Overview
Problem
In LTE-Advanced systems, the introduction of DL New Carrier Type (NCT) as a secondary carrier leads to uneven distribution of radio terminals in idle state, concentrating them in Legacy PCells, which hampers efficient cell reselection and connection setup processes due to inappropriate configuration of Legacy PCell and NTCC PCell ratios.
Innovation Solution
Implementing a radio communication system where radio terminals recognize cell types and select cells based on specific criteria, including decision thresholds, offset values, and priorities, to distribute radio terminals appropriately across different types of cells, thereby preventing concentration of connection setup processes in specific cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DL New Carrier Type (NCT) is introduced as a secondary carrier, then system capacity and resource utilization are improved, but radio terminals in idle state become unevenly distributed and concentrate in Legacy PCells
Solution Approach 1:
The patent applies local quality by configuring different cell selection criteria for different cell types. Legacy PCells use one set of criteria while NTCC PCells use another set, allowing each cell type to be optimized for its specific characteristics. This enables NTCC PCells to attract more idle terminals while Legacy PCells maintain their traditional performance, achieving both improved system capacity and more uniform terminal distribution.
Solution Approach 2:
The patent changes key parameters of the cell selection criteria, specifically adjusting decision thresholds (Qrxlevmin, Qqualmin) and offset values (Qoffset) based on cell type. By modifying these parameters differently for Legacy PCells and NTCC PCells, the system can control terminal distribution patterns to achieve better load balancing while maintaining overall system productivity.
2Stability of the object's composition
If cell selection criteria are configured to distribute terminals across NTCC PCells, then terminal distribution improves, but connection setup process complexity increases
Solution Approach 1:
The patent segments the cell selection process into distinct phases: initial cell search, cell type identification, and type-specific criteria evaluation. By dividing the complex selection process into manageable segments with clear decision points, terminals can efficiently determine which cell type they are evaluating and apply the appropriate criteria, reducing overall process complexity while maintaining good terminal distribution.
Solution Approach 2:
The patent implements preliminary action by having terminals identify cell types early in the selection process, before applying the full set of selection criteria. This preliminary identification allows terminals to prepare the appropriate criterion set in advance, streamlining the subsequent evaluation process and reducing connection setup complexity while achieving desired terminal distribution.
3Productivity
If Legacy PCell and NTCC PCell ratios are adjusted for optimal distribution, then cell reselection efficiency improves, but system configuration complexity increases
Solution Approach 1:
The patent enables self-service by allowing the system to automatically determine optimal Legacy PCell and NTCC PCell ratios based on deployed cell characteristics and traffic patterns. Rather than requiring manual configuration, the system autonomously adjusts these ratios to achieve optimal cell reselection efficiency, reducing configuration complexity while maintaining high productivity.
Solution Approach 2:
The patent implements feedback mechanisms that monitor terminal distribution patterns and cell reselection performance in real-time. Based on this feedback, the system dynamically adjusts the ratio of Legacy PCells to NTCC PCells and refines cell selection criteria configurations, achieving optimal reselection efficiency without complex manual configuration while adapting to changing system conditions.
Data Source
AI summary
The present invention is a radio communication system in which a radio station and a radio terminal communicate with each other. The radio communication system has a control means with which at least one of the radio stations controls a plurality of types of cells by using one radio access technology, a recognition means with which the radio terminal recognizes the types of the cells, and a cell selection means with which the radio terminal selects the cell based on cell selection criteria based on the types of the cells.