Inter-RAT Cell Reselection Using Signal Quality Offsets

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Solution Overview

Problem

In heterogeneous wireless communication networks with multiple radio access technologies, mobile stations face challenges in effectively performing cell reselection due to the lack of priority information from serving cells, leading to increased power consumption and potential service quality deterioration.

Innovation Solution

A method where a mobile station determines if priority information for the first radio access technology is provided, and if not, performs inter-RAT cell reselection based on measured values from the second radio access technology without considering its priority information, selecting cells with better signal quality by offsetting measured values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If priority-based inter-RAT cell reselection is performed, then cell reselection efficiency is improved, but the system requires priority information from the serving cell which may not be provided

Engineering Contradiction:
Improvecell reselection efficiencyVSAvoidpriority information
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent changes the cell reselection parameters by introducing measured value offsets (Qoffset) and hysteresis margins that allow the mobile station to perform effective cell reselection based on signal quality measurements even without priority information from the serving cell

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The mobile station performs self-service by autonomously determining cell reselection based on its own measurements of neighboring cells and applying offset values, without requiring priority information from the serving cell

Inventive Principle:
Principle #25Self-service

2Reliability

If the mobile station continuously measures signals in all searchable frequency bands for cell reselection, then cell quality is improved, but power consumption increases

Engineering Contradiction:
Improvecell qualityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by introducing offset values (Qoffset) that are specific to each neighboring cell, allowing the mobile station to prioritize measurements of cells with better signal characteristics while reducing unnecessary measurements of cells with poor signal quality

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The mobile station performs partial measurements by only evaluating neighboring cells that meet certain signal quality thresholds after applying offsets, rather than continuously measuring all cells in all frequency bands

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2378815B1Method and apparatus for performing cell reselection in wireless communication system
Publication Date: 2016.04.13 LG ELECTRONICS INC
  • EP2378815B1 patent drawingFigure 1
  • EP2378815B1 patent drawingFigure 2
  • EP2378815B1 patent drawingFigure 3

AI summary

An apparatus and method of performing cell reselection in a wireless communication system is provided. A mobile station determines whether first priority information for the first RAT is provided by the serving cell, and receives second priority information of a second RAT from the serving cell. The mobile station performs inter-RAT cell reselection based on the first and second priority information if the first priority information for the first RAT is provided. The mobile station performs cell reselection toward the second RAT based on measured values of cells of the second RAT without considering the second priority information if the first priority information for the first RAT is not provided.