Zero-Power CSI-RS Configuration Handling for Interference Management

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Solution Overview

Problem

In wireless communication systems, particularly in 3GPP LTE, there is a need for efficient handling of zero-power Channel State Information Reference Signal (CSI-RS) configurations for discovery signals to manage muting between CSI-RS transmissions among cells, which is crucial for reducing interference and improving user packet throughput in scenarios with multiple small cells.

Innovation Solution

A method for a user equipment (UE) to receive and handle zero-power CSI-RS configurations, allowing muting between CSI-RS transmissions, which involves data rate matching and specific configurations to support efficient CSI-RS behavior, particularly in scenarios with multiple small cells and varying transmission modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If zero-power CSI-RS configurations are used for muting between DRS transmissions, then interference is reduced and user packet throughput is improved, but device complexity and configuration management become more complex

Engineering Contradiction:
Improveuser packet throughputVSAvoidconfiguration management
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the muting pattern parameters (periodicity, subframe offset, resource block allocation) of zero-power CSI-RS configurations. This allows the system to optimize interference management and user packet throughput by adapting these parameters based on traffic conditions and cell load, rather than using fixed configurations. The base station can modify these parameters to balance between reducing interference through muting and maintaining configuration simplicity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple small cells are deployed in macro cell coverage, then system capacity and coverage are expanded, but interference increases when all small cells are turned on

Engineering Contradiction:
Improvesystem capacityVSAvoidinterference
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements periodic action through the use of periodic muting patterns configured via zero-power CSI-RS. Small cells periodically mute their CSI-RS transmissions according to configured patterns (with different periodicities and subframe offsets), creating time-division multiplexing effects. This periodic muting reduces interference between neighboring small cells while maintaining system capacity, as cells take turns being active and others remain muted during their respective transmission intervals.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies preliminary action by pre-configuring muting patterns and resource allocations for small cells before interference issues arise. The base station provides advance configuration information to small cells about when to mute transmissions, allowing them to proactively avoid interfering with each other. This preliminary configuration enables smooth coordination among multiple small cells without requiring real-time interference management.

Inventive Principle:
Principle #10Preliminary action

3Speed

If fast transition between on/off states of small cells is implemented, then service quality and responsiveness are improved, but interference management becomes more challenging

Engineering Contradiction:
Improvetransition speedVSAvoidinterference
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamics by enabling flexible and rapid adjustment of muting pattern configurations for small cells. The system can dynamically change periodicity, subframe offsets, and resource allocations based on real-time traffic conditions and interference measurements. This dynamic capability allows small cells to quickly transition between active and muted states while maintaining coordinated interference management, as the configurations can be updated without requiring complete system reconfiguration.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3186905B1Method for handling zero power channel state information reference signal configurations for discovery signals in wireless communication system
Publication Date: 2021.08.18 LG ELECTRONICS INC
  • EP3186905B1 patent drawingFigure 1~2
  • EP3186905B1 patent drawingFigure 3
  • EP3186905B1 patent drawingFigure 4

AI summary

A method and apparatus for receiving a zero-power channel state information reference signal (CSI-RS) configuration in a wireless communication system is provided. A user equipment (UE) receives at least one first zero-power CSI-RS configuration for data rate matching on a discovery reference signal (DRS) from a network, and receives a second zero-power CSI-RS configuration for interference measurement from the network. The at least one first zero-power CSI-RS configuration is not used for the second zero-power CSI-RS configuration.