Fourier Transform Matrix Sector Isolation Calibration

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Solution Overview

Problem

Existing wireless communication systems employing Fourier transform matrices face challenges in maintaining optimal sector-to-sector isolation (SSI) due to imbalances in gain and phase between transmit paths, leading to degraded signal quality and data transmission rates.

Innovation Solution

A method and system that calibrate and adjust the gains and phases of transmit paths between Fourier transform matrices by using a known test signal, phase shifter, and attenuator to minimize output and achieve balanced sector-to-sector isolation, involving setting one matrix to pass-through mode, adjusting gains and phases to achieve null angles, and using a correlator to determine necessary adjustments for improved isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If Fourier transform matrices are used to distribute power amongst amplifiers, then power distribution efficiency is improved, but sector-to-sector isolation degrades due to gain and phase imbalances between transmit paths

Engineering Contradiction:
Improvepower distribution efficiencyVSAvoidsector-to-sector isolation
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent adjusts gain and phase parameters of individual transmit paths to compensate for imbalances. By dynamically changing these parameters, the system maintains optimal sector-to-sector isolation while preserving the power distribution efficiency of the Fourier transform matrix architecture.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system employs feedback mechanisms to monitor and adjust transmit path characteristics. This allows continuous optimization of gain and phase settings to maintain high sector-to-sector isolation performance while utilizing the Fourier transform matrix for efficient power distribution.

Inventive Principle:
Principle #23Feedback

2Device complexity

If gain and phase imbalances exist between transmit paths, then system complexity is reduced, but signal quality and data transmission rates degrade

Engineering Contradiction:
Improvesystem complexityVSAvoidsignal quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent performs preliminary calibration of gain and phase settings during system initialization or maintenance periods. This preliminary adjustment ensures optimal signal quality during normal operation without requiring continuous complex adjustments, thus balancing simplicity and performance.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If gain and phase imbalances exist between transmit paths, then device complexity is reduced, but data transmission rates decrease

Engineering Contradiction:
Improvedevice complexityVSAvoiddata transmission rates
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The system performs preliminary calibration of transmit paths to optimize data transmission rates before normal operation begins. This upfront adjustment ensures high productivity without requiring continuously complex adjustment mechanisms during data transmission.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2069871B1Method and apparatus for improving sector-to-sector isolation in a fourier transform matrix system
Publication Date: 2012.10.03 MOTOROLA MOBILITY LLC
  • EP2069871B1 patent drawingFigure 1
  • EP2069871B1 patent drawingFigure 2
  • EP2069871B1 patent drawingFigure 3

AI summary

A method for providing increased sector-to-sector isolation when transmitting data between a plurality of Fourier transform matrices (105,110), each having an input Fourier transform matrix (FTM), an output FTM, and a plurality of transmit paths therebetween is disclosed. The method includes applying a tone to one of the plurality of transmit paths (410) so that a correlated output can be produced, measuring an output of the output FTM, correlating the output of the output FTM against the tone applied to produce a correlated output (320), adjusting a phase of the transmit path such that a direct current value of the correlated output is minimized, and adjusting an attenuation of the transmit path such that the direct current of the correlated output is minimized.