Heterogeneous LTE Measurement Resource Restriction Patterns

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Solution Overview

Problem

In heterogeneous LTE networks, issues such as interference from aggressor cells can lead to unreliable detection of system information changes, inadequate cell range extension, inaccurate mobility state evaluation, and increased probability of radio link failures due to limitations in time domain measurement resource restriction patterns and S-Measure definitions.

Innovation Solution

Implementing enhanced time domain measurement resource restriction patterns, shifting paging occasions to protected subframes, defining physical cell ID ranges for pico cells, and configuring S-Measure to include RSRQ measurements, along with reporting measurement resource restriction patterns and mobility state information in radio link failure reports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If time domain measurement resource restriction patterns are used in heterogeneous LTE networks, then interference from aggressor cells is reduced, but detection of system information changes becomes unreliable

Engineering Contradiction:
Improveinterference from aggressor cellsVSAvoiddetection of system information changes
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system segments measurement resources by creating separate measurement subframe patterns for different cell types (macro cells and pico cells). This allows UEs to measure pico cell signals during specific subframes that are protected from macro cell interference, while maintaining separate measurement opportunities for system information detection, thereby resolving the conflict between interference reduction and reliable detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a time dimension by utilizing specific subframe patterns and modification periods. System information changes are detected at modification period boundaries, which are timed to occur during protected subframes where interference is minimized. This temporal dimension allows the system to maintain both interference protection and reliable detection capabilities.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If measurement resource restriction patterns are applied, then cell range extension is improved, but mobility state evaluation becomes inaccurate

Engineering Contradiction:
Improvecell range extensionVSAvoidmobility state evaluation
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The measurement resource restriction patterns are designed to serve multiple functions simultaneously: they enable cell range extension by allowing pico cell measurements during protected subframes, while also providing sufficient measurement opportunities for accurate mobility state evaluation. The patterns are configured to ensure UEs have access to both restricted and unrestricted subframes for different measurement purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If paging occasions are shifted to protected subframes, then interference-related failures are reduced, but system complexity increases

Engineering Contradiction:
Improveinterference-related failuresVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements periodic paging occasions that are synchronized with the modification period boundaries and protected subframe patterns. By making paging occasions periodic and predictable, the system reduces complexity compared to arbitrary scheduling, while still ensuring they occur during protected subframes to minimize interference-related failures.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2761786B1Enhancment and improvement for hetnet deployments
Publication Date: 2017.09.13 BLACKBERRY LTD
  • EP2761786B1 patent drawingFigure 1~2
  • EP2761786B1 patent drawingFigure 3~4
  • EP2761786B1 patent drawingFigure 5

AI summary

A method is provided for operating a UE in a wireless communications network. The method comprises, when a measurement resource restriction is configured, verifying, by a UE, whether stored system information is valid by examining a system information identifier after a modification period has occurred.