LTE Interference Suppression via Reference Signal Measurement

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Solution Overview

Problem

In LTE communication systems, especially in dynamic TDD and full-duplex FDD modes, uplink and downlink signals often interfere with each other, leading to reduced network throughput and communication quality due to the increased demand for spectrum resources and the proximity of user terminals.

Innovation Solution

A method where an interfered-with end receives reference signals from both a base station and a potential interfering source, compares their signal strengths, and sends interference information to coordinate scheduling to avoid allocating the same time-frequency resources for uplink and downlink signals, thereby suppressing mutual interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dynamic TDD working mode or full-duplex FDD working mode is used to improve spectrum utilization, then spectrum utilization is improved, but interference between uplink and downlink signals increases

Engineering Contradiction:
Improvespectrum utilizationVSAvoidinterference between uplink and downlink signals
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The interfered-with terminal performs preliminary measurement of reference signals from both the base station and potential interfering sources before actual data transmission. This advance measurement enables the terminal to identify interfering sources and report interference information to the base station, allowing scheduling decisions to be made that prevent interference before it occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The interfered-with terminal feeds back interference information (including interference identification and signal strength) to the base station. This feedback mechanism enables the base station to adjust scheduling decisions dynamically, coordinating between different terminals to avoid simultaneous uplink-downlink transmissions that would cause interference.

Inventive Principle:
Principle #23Feedback

2Productivity

If user terminals are located near each other to increase network capacity, then network capacity is improved, but mutual interference between terminals increases

Engineering Contradiction:
Improvenetwork capacityVSAvoidmutual interference between terminals
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The interference suppression mechanism is applied locally at each interfered-with terminal based on its specific measurement results. Each terminal independently measures reference signals, identifies local interfering sources, and reports to its serving base station. This localized approach allows the system to handle interference specific to each terminal's location and environment.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes scheduling parameters (time-frequency resource allocation) based on measured signal strength parameters. When interference is detected above a certain threshold, the base station adjusts the scheduling parameters to allocate different time-frequency resources to interfering and interfered-with terminals, thereby suppressing interference.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If reference signal measurement and interference coordination is implemented to suppress interference, then interference is suppressed, but system complexity increases

Engineering Contradiction:
Improveinterference suppressionVSAvoidsystem complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The interfered-with terminal performs self-measurement of reference signals from potential interfering sources and autonomously generates interference information reports. This self-service approach eliminates the need for complex centralized measurement and coordination mechanisms, reducing overall system complexity while achieving interference suppression.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses reference signals (which are known pilot signals) as copies of the actual data signals to measure and predict potential interference. By measuring these simplified reference signals instead of analyzing complex data signals, the system reduces measurement complexity while still accurately identifying interfering sources.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2981143B1Interference suppression method, related device, and system
Publication Date: 2020.07.08 HUAWEI TECH CO LTD
  • EP2981143B1 patent drawingFigure 1~2
  • EP2981143B1 patent drawingFigure 3
  • EP2981143B1 patent drawingFigure 4~5

AI summary

Embodiments of the present invention disclose an interference suppression method and a related device and system. The method includes: sending, on a specified time-frequency resource, a first reference signal or a first reference signal group to an interfered-with end; receiving interfering source information sent by the interfered-with end, where the interfering source information includes an interference identifier used for indicating whether a potential interfering source sending a reference signal on the specified time-frequency resource causes interference to the interfered-with end; and if the interference identifier in the interfering source information indicates that the potential interfering source sending the reference signal on the specified time-frequency resource causes interference to the interfered-with end, determining that the potential interfering source is an interfering source, or if the interference identifier in the interfering source information indicates that the potential interfering source sending the reference signal on the specified time-frequency resource causes interference to the interfered-with end, determining that the potential interfering source is an interfering source. According to the present invention, mutual interference between uplink and downlink signals of terminals located in a same cell or different cells can be suppressed.