UE CRS Mitigation Detection and RSRP Measurement Adjustment

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Solution Overview

Problem

The introduction of network-based Cell Specific Reference Signal (CRS) mitigation in LTE standards may degrade radio resource management and demodulation performance at user equipment (UE) devices, particularly due to inaccurate reference signal received power (RSRP) measurements and increased power consumption, especially when neighboring cells mute CRS signals without UE notification.

Innovation Solution

User equipment (UE) devices employ autonomous detection methods or network-assisted approaches to determine whether network-based CRS mitigation is used by neighboring or serving cells, adjusting their receiver demodulation and radio resource management algorithms to mitigate interference and optimize performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If network-based CRS mitigation is introduced to reduce interference, then interference mitigation performance is improved, but measurement precision of RSRP degrades

Engineering Contradiction:
ImproveCRS interferenceVSAvoidRSRP measurement accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where the UE reports detected CRS muting patterns back to the network, enabling the network to adjust and optimize muting configurations. This feedback loop allows the system to maintain interference mitigation benefits while improving measurement accuracy through adaptive configuration adjustments.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes key parameters including introducing CRS muting indication information, adjusting RSRP measurement configurations, and modifying demodulation reference signal (DM-RS) based measurement parameters. These parameter changes enable the system to adapt to CRS muting scenarios while maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If network-based CRS mitigation is introduced to reduce interference, then interference mitigation performance is improved, but device complexity increases

Engineering Contradiction:
ImproveCRS interferenceVSAvoidUE receiver complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the network pre-configure CRS muting patterns and provide muting indication information to the UE before actual measurements occur. This allows the UE to prepare appropriate measurement configurations and algorithms in advance, reducing real-time processing complexity while maintaining interference mitigation effectiveness.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If autonomous detection of CRS muting is implemented, then adaptability is improved, but loss of time increases due to detection overhead

Engineering Contradiction:
ImproveAdaptability to CRS mutingVSAvoidDetection time overhead
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent implements self-service through autonomous detection mechanisms where the UE independently detects CRS muting patterns without requiring extensive network assistance. The UE uses its own processing capabilities to identify muting configurations, reducing dependency on network signaling and minimizing time overhead while maintaining high adaptability to different muting scenarios.

Inventive Principle:
Principle #25Self-service

4Object-affected harmful factors

If CRS muting is applied in neighboring cells, then interference mitigation is improved, but reliability of demodulation performance degrades

Engineering Contradiction:
ImproveNeighboring cell CRS interferenceVSAvoidDemodulation performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies segmentation by separating measurement and demodulation processes into distinct configurations. It introduces separate parameter sets for RSRP measurements in CRS-muted regions versus non-muted regions, and for demodulation using DM-RS based methods. This segmentation allows the system to maintain reliable demodulation performance while still benefiting from interference mitigation through targeted CRS muting in specific resource blocks.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3665846B1Network based CRS mitigation
Publication Date: 2023.11.29 APPLE INC
  • EP3665846B1 patent drawingFigure 1
  • EP3665846B1 patent drawingFigure 2A
  • EP3665846B1 patent drawingFigure 2A

AI summary

An apparatus of a user equipment (UE), comprises one or more baseband processors to receive one or more subframes from a cell of a network, and to detect a Cell Specific Reference Signal (CRS) transmission pattern in the one or more subframes to determine whether CRS mitigation is used by the cell, wherein the one or more baseband processors are to adjust processing of the one or more subframes when CRS mitigation is used. The apparatus further includes a memory to store the one or more subframes.