UE Interference Cancellation via Synthesized CRS in 5G

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Solution Overview

Problem

In 5G networks, interference with reference signals affects the accuracy of measurements such as reference signal received power (RSRP), which is crucial for mobility decisions and UE management, as base stations do not transmit cell reference signals, making traditional interference cancellation methods ineffective.

Innovation Solution

A user equipment (UE) is configured to measure and remove contributions from interfering cells by identifying cell IDs, thereby isolating and estimating the power measurement of the serving cell's reference signal, including removing interference from synchronization signal blocks, channel state information-reference signals, physical downlink control channels, and physical downlink shared channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional CRS-based interference cancellation is used, then interference removal is effective in LTE networks, but it cannot be applied in 5G networks where CRS is not transmitted

Engineering Contradiction:
Improveinterference cancellation effectivenessVSAvoidcompatibility with 5G network architecture
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a virtual copy of the CRS signal by generating a synthesized cell reference signal that mimics the characteristics of the actual CRS. This synthesized signal is then used for interference cancellation purposes, allowing the system to apply LTE-style interference cancellation techniques in 5G networks where actual CRS transmission is eliminated. The copying principle enables the preservation of useful interference cancellation functionality while adapting to the new 5G signal structure.

Inventive Principle:
Principle #26Copying

2Productivity

If base stations do not transmit CRS to improve spectral efficiency, then network capacity increases, but interference cancellation accuracy deteriorates

Engineering Contradiction:
Improvenetwork capacityVSAvoidinterference cancellation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by pre-calculating and storing synthesized CRS signals for multiple possible interfering cells before actual interference cancellation is needed. These synthesized reference signals are prepared in advance based on known cell configurations and are readily available when interference cancellation operations are required, enabling fast and accurate interference removal without impacting real-time network capacity.

Inventive Principle:
Principle #10Preliminary action

3Speed

If UE measures reference signals in the presence of interfering cell transmissions, then measurement speed is maintained, but measurement accuracy deteriorates

Engineering Contradiction:
Improvemeasurement speedVSAvoidRSRP measurement accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of interfering cell transmissions into a beneficial process by using the synthesized CRS to model and subtract the interference component from the received signal. Instead of treating interfering signals as mere noise to be avoided, the system actively utilizes knowledge of potential interferers to construct cancellation signals, thereby transforming the measurement challenge into an opportunity for improved accuracy through interference exploitation and removal.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4465559A1UE-based interference cancellation in 5g networks
Publication Date: 2024.11.20 T MOBILE US INC
  • EP4465559A1 patent drawingFigure 1
  • EP4465559A1 patent drawingFigure 2
  • EP4465559A1 patent drawingFigure 3

AI summary

System and methods for estimating a reference signal received power (RSRP) for a reference signal of a serving cell for a user equipment (UE), based on measuring received reference signals and removing a contribution of an interfering cell from the reference signals, are described herein. The reference signals may be received on a same frequency at a same transmission time interval by the UE. At least one of the serving cell and the interfering cell may be associated with Fifth Generation (5G) or later technology.