MIMO Antenna Correlation Estimation for Signal Quality

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Solution Overview

Problem

Mobile device MIMO antenna systems face performance degradation due to changes in radiated channel conditions and user interactions, such as hand position, which impair RF reception and lead to gain imbalance and high antenna correlation, affecting signal quality and throughput.

Innovation Solution

A method and apparatus that utilize a correlation estimator to obtain real-time performance measurements, adaptively select MIMO antennas, and adjust antenna pairs based on estimated correlation values, using a CQI table and SNR measurements to improve antenna diversity and reduce correlation, thereby enhancing signal quality and throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If static antenna configurations are used in MIMO systems, then device complexity is reduced, but antenna correlation increases under varying channel conditions and user interactions

Engineering Contradiction:
Improveantenna configuration complexityVSAvoidsignal quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic antenna configuration by continuously monitoring channel conditions and user interaction parameters, then adaptively selecting antenna pairs with lowest correlation. The system transitions from static to dynamic antenna selection based on real-time measurements of channel quality indicators and correlation coefficients, resolving the contradiction between simplicity and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms by measuring antenna correlation and channel conditions, comparing them against thresholds, and adjusting antenna selections accordingly. This closed-loop control ensures optimal antenna pairs are selected under varying conditions while maintaining manageable system complexity through automated decision-making.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If antenna pairs are fixed regardless of operating conditions, then ease of operation is improved, but antenna correlation and gain imbalance worsen under varying channel conditions

Engineering Contradiction:
Improveantenna selection operationVSAvoidantenna correlation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The MIMO system performs self-optimization by automatically measuring channel conditions and antenna correlation, then selecting optimal antenna pairs without user intervention. The system serves itself by implementing adaptive antenna selection based on real-time performance metrics, maintaining ease of operation while improving correlation performance.

Inventive Principle:
Principle #25Self-service

3Reliability

If real-time antenna adaptation is implemented, then antenna correlation is reduced, but measurement and control complexity increases

Engineering Contradiction:
Improveantenna correlationVSAvoidmeasurement and control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements partial adaptation by focusing measurements and control efforts only on the most critical parameters (channel quality indicators and antenna correlation coefficients) rather than comprehensively monitoring all possible variables. This selective measurement approach reduces complexity while maintaining effective real-time antenna selection.

Inventive Principle:
Principle #16Partial or excessive action

4Manufacturing precision

If static figure-of-merit requirements are used, then manufacturing precision is improved, but adaptability to different operating conditions deteriorates

Engineering Contradiction:
Improveantenna system design precisionVSAvoidoperating condition adaptability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system maintains precise antenna designs with fixed physical parameters but introduces adaptability through dynamic selection of antenna pairs based on operating conditions. By changing which antennas are active rather than changing the antennas themselves, the system preserves manufacturing precision while achieving versatility across different channel conditions and user interactions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9608711B2Apparatus and methods for antenna correlation estimation in a multi-antenna system
Publication Date: 2017.03.28 GOOGLE TECHNOLOGY HOLDINGS LLC
  • US9608711B2 patent drawing
  • US9608711B2 patent drawing
  • US9608711B2 patent drawing

AI summary

Disclosed apparatuses obtain real-time performance measurements and adaptively select multiple-input, multiple-output (MIMO) antennas to improve MIMO antenna performance. A correlation estimator determines an approximation of instantaneous antenna correlation values. One method includes obtaining a channel quality indicator (CQI) measurement for first and second antennas of a mobile device. The method determines a composite CQI for the two antennas and estimates the antenna correlation for the first and second antennas based on the composite CQI. The method can include performing a lookup operation in a CQI table mapping composite CQI to coding rates. The method can include obtaining a signal-to-noise ratio (SNR) measurement for the first and second antennas of the mobile device, and estimating the antenna correlation for the first and second antennas based on the composite CQI and the SNR measurement.