Cell Reselection Margin Adjustment for Coverage Bias
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, particularly in NB-IoT, determining the optimal cell change is challenging due to varying channel conditions, which can lead to suboptimal cell selection caused by measurement bias and differing coverage levels between cells.
Innovation Solution
A method that ranks cells based on defined criteria and evaluates the suitability of a cell change by considering the margin of difference in coverage levels between the current and target cells, using tables to map coverage level combinations to margin values, thereby preventing cell changes to less suitable cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cell reselection is performed based on standard measurement criteria, then cell change speed is improved, but measurement precision deteriorates due to coverage level differences and measurement bias
Solution Approach 1:
The patent introduces a coverage level parameter that modifies the cell reselection measurement process. By determining the coverage level of the serving cell and adjusting the measurement evaluation accordingly, the system accounts for measurement bias in different coverage conditions. This parameter change enables accurate cell selection across varying coverage levels while maintaining efficient reselection timing.
Solution Approach 2:
The patent introduces an intermediate evaluation step that acts as a mediator between standard measurement criteria and cell reselection decisions. This intermediate layer evaluates whether a target cell is suitable for reselection by considering the coverage level and measurement bias, preventing premature or inaccurate cell changes while maintaining efficient reselection processes.
2Productivity
If measurement margin is reduced for faster cell reselection, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The patent dynamically adjusts the measurement margin parameter based on the determined coverage level. Instead of using a fixed margin that would require large values for precision, the system adapts the margin to the specific coverage conditions, enabling both fast reselection and accurate measurement evaluation across different coverage scenarios.
Solution Approach 2:
The patent makes the measurement margin dynamic rather than static. The margin value changes based on the coverage level determination, allowing the system to optimize between reselection speed and measurement precision adaptively. This dynamic approach eliminates the need for conservative fixed margins while maintaining accuracy.
3Measurement precision
If coverage level determination is added to cell reselection process, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-service mechanism where the user equipment autonomously determines its own coverage level based on measurement results and system information. This self-determination process eliminates the need for complex network-side coverage level assignment procedures, reducing overall system complexity while maintaining measurement precision.
Solution Approach 2:
The patent performs coverage level determination as a preliminary action before cell reselection evaluation. By determining the coverage level in advance and using it to adjust subsequent measurement evaluations, the system integrates the additional functionality smoothly into the existing reselection process without creating complex conditional logic during the critical reselection moment.
Data Source
AI summary
A method is performed in a wireless communication system (10). The method may comprise ranking a first cell (22A) and a second cell (22B) of the wireless communication system (10) according to one or more defined cell-ranking criteria. The method may also comprise evaluating that the second cell (22B) has met a reselection criterion for a wireless device (16), provided that the second cell (22B) is ranked better than the first cell (22A) by at least a margin. The value of the margin may depend on a coverage level of the wireless device (16) with respect to the first cell (22A) and a coverage level of the wireless device (16) with respect to the second cell (22B).