Spatial Listen-Before-Talk Protocol for MIMO Interference

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Solution Overview

Problem

Conventional Listen-Before-Talk (LBT) protocols in wireless communication systems, particularly with advanced MIMO configurations, face inefficiencies due to the use of fixed interference thresholds based on omni-directional energy detection, leading to unsatisfactory performance in 5G and beyond scenarios.

Innovation Solution

The implementation of a spatial LBT procedure that takes into account MIMO configuration information, allowing for accurate measurement of effective interference and adaptive adjustment of power detection thresholds, thereby improving channel assessment and reducing interference-related failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional omni-directional energy detection with fixed interference thresholds is used, then the LBT protocol is simple to implement, but the performance is unsatisfactory in advanced MIMO configurations

Engineering Contradiction:
ImproveImplementation simplicityVSAvoidLBT protocol performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the detection parameters from omni-directional energy detection to spatially-selective detection based on MIMO configuration. The system adapts the power detection threshold and detection direction according to the MIMO rank and antenna configuration, transforming the fixed threshold into a dynamic parameter that varies with spatial conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic adaptation of the LBT detection process based on real-time MIMO configuration information. The system dynamically selects detection beams and adjusts thresholds according to the transmitted MIMO rank, making the previously static omni-directional detection into a dynamic spatially-adaptive process.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If spatial LBT procedure with MIMO configuration information is implemented, then channel assessment accuracy is improved, but the device complexity increases

Engineering Contradiction:
ImproveChannel assessment accuracyVSAvoidLBT procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary determination of MIMO configuration information before executing the LBT procedure. By pre-obtaining the MIMO rank and antenna configuration, the system prepares the detection parameters in advance, avoiding complex real-time calculations during the actual LBT process and reducing operational complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces MIMO configuration information as an intermediary that bridges the gap between simple energy detection and complex spatial processing. This intermediary parameter enables the system to select appropriate detection beams and thresholds without requiring full spatial processing complexity, acting as a control variable that simplifies the overall system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If fixed power detection threshold is used, then the LBT protocol is easy to operate, but interference-related failures increase

Engineering Contradiction:
ImproveLBT operation simplicityVSAvoidLBT message exchange success rate
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent transforms the fixed power detection threshold into a variable parameter that changes based on MIMO configuration. The threshold is adjusted according to the MIMO rank and spatial conditions, allowing the system to maintain high reliability across different configurations while preserving operational simplicity through automated parameter selection.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3677084B1Apparatuses and methods for a spatial listen-before-talk protocol
Publication Date: 2022.03.02 QUALCOMM INC
  • EP3677084B1 patent drawingFigure 1
  • EP3677084B1 patent drawingFigure 2A~2D
  • EP3677084B1 patent drawingFigure 3

AI summary

A method, apparatus, and computer-readable medium at a transmitting network device or a target network device in a listen-before-talk (LBT) session that employ a spatial LBT procedure is disclosed. The spatial LBT procedure takes into account multiple-input multiple-output (MIMO) configuration information in measuring an effective interference. Accordingly, the spatial LBT procedure enables the transmitting network device or the target network device to more accurately measure an interference and make a more accurate decision on whether a channel is clear, and thus improves the system-wide performance. Also, the spatial LBT procedure allows the transmitting network device or the target/receiving network device to adaptively adjust the LBT power detection threshold when the MIMO configuration is not available. This also enables the network devices to more accurately measure interference and make a more accurate decision on whether the channel is clear, especially when advanced MIMO technologies are deployed in 5G or beyond.