CRS Muting Based on UE Capability for LTE Interference Control

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Solution Overview

Problem

Existing LTE networks face challenges in minimizing inter-cell interference and optimizing downlink throughput for low-complexity UEs in even further enhanced Machine Type Communication (efeMTC), particularly in bandwidth-reduced scenarios, where current CRS muting techniques do not effectively account for UE capabilities and result in unnecessary power consumption and interference.

Innovation Solution

Implementing frequency domain CRS muting based on UE capability signaling, allowing BL UEs to indicate non-reliance on CRS outside their narrowband or wideband, and configuring CRS muting parameters through semi-static and dynamic signaling to optimize channel estimation and reduce interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CRS muting is applied in LTE networks, then downlink throughput is improved and inter-cell interference is reduced, but connection drop rate increases and UE performance deteriorates

Engineering Contradiction:
Improvedownlink throughputVSAvoidconnection drop rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies different CRS muting configurations to different frequency regions (resource blocks) based on local interference conditions and UE requirements. Instead of uniform muting across the entire bandwidth, the system selectively mutes CRS in specific resource blocks where interference is problematic, while maintaining CRS transmission in other regions where UEs need reliable channel estimation, thus balancing throughput improvement with connection reliability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces dynamic CRS muting configuration where the muting pattern can be adjusted based on traffic conditions, interference levels, and UE capabilities. The system can switch between different muting patterns and activate/deactivate muting in response to changing network conditions, allowing optimization of downlink throughput while maintaining connection stability through adaptive control

Inventive Principle:
Principle #15Dynamics

2Productivity

If CRS muting is applied to reduce inter-cell interference, then downlink throughput increases, but network power consumption increases due to unnecessary muting

Engineering Contradiction:
Improvedownlink throughputVSAvoidnetwork power consumption
Core Design Contradiction:
ProductivityVSUse of energy by stationary object

Solution Approach 1:

The patent implements partial CRS muting where only specific resource blocks experiencing interference are muted, rather than applying muting across the entire frequency bandwidth. This partial action approach achieves interference reduction and throughput improvement in affected regions while avoiding unnecessary power consumption from muting CRS in regions where it is not needed, optimizing the trade-off between performance and energy efficiency

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the muting parameter configuration based on observed interference levels and traffic conditions. The system dynamically adjusts which resource blocks are muted and the muting pattern, transitioning from static full-bandwidth muting to adaptive selective muting, thereby reducing network power consumption by avoiding unnecessary CRS muting while maintaining throughput benefits where interference occurs

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If CRS muting is applied without considering UE capabilities, then inter-cell interference is reduced, but UE performance and power efficiency deteriorate

Engineering Contradiction:
Improveinter-cell interferenceVSAvoidUE power efficiency
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent segments the frequency bandwidth into different resource block groups and applies CRS muting selectively to specific segments based on UE capabilities and interference conditions. Instead of uniform muting across the entire bandwidth, the system divides the spectrum and applies muting only where necessary for each UE, reducing inter-cell interference while preserving UE power efficiency by avoiding unnecessary muting in capability-matched regions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adjusts CRS muting parameters (which resource blocks to mute, muting pattern, periodicity) based on reported UE capabilities such as bandwidth support and channel estimation requirements. The system dynamically changes muting configuration parameters to match UE capabilities, ensuring that muting is applied only when beneficial for interference reduction while maintaining UE power efficiency and performance

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3603257B1Design of cell specific reference signal (CRS) muting for even further enhanced machine type communication (efemtc)
Publication Date: 2025.07.23 APPLE INC
  • EP3603257B1 patent drawingFigure 1
  • EP3603257B1 patent drawingFigure 2
  • EP3603257B1 patent drawingFigure 3

AI summary

A network device such as an evolved NodeB (eNB) or next generation NodeB (gNB) can configure a set of user equipment (UE) for cell reference signal (CRS) muting in order to provide better channel quality and power efficiency in communications. Where an eNB mutes CRS transmissions that are not needed by any UE, an improvement in downlink throughput and reduce connection drop rate can be generated. A CRS muting capability can be determined based on a user equipment (UE) capability information. According to the CRS muting capability of a UE, CRS muting can be generated in a physical channel outside of a narrow band (NB) or a wide band (WB) plus / minus X physical resource blocks (PRBs), wherein X is a non-negative integer, based on the CRS muting capability.