Diagonal Loading Coefficient for IRC Noise Matrix

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Solution Overview

Problem

The existing methods for determining the specific value of diagonal loading in Interference Rejection Combining (IRC) systems for orthogonal frequency division multiplexing are inadequate, affecting the estimation accuracy of the noise matrix and subsequently the interference rejection capability.

Innovation Solution

A method and device for determining a diagonal loading coefficient based on noise power and interference power at the user's location, where the coefficient is inversely proportional to the interference power over noise power, used to diagonally load the noise matrix for improved equalization in IRC systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If diagonal loading is applied to improve noise matrix estimation accuracy, then the interference rejection capability is improved, but the specific value of diagonal loading is not well determined leading to suboptimal performance

Engineering Contradiction:
Improvenoise matrix estimation accuracyVSAvoidinterference rejection capability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the parameter of diagonal loading value from arbitrary or fixed to dynamically adjusted based on signal-to-interference-plus-noise ratio (SINR). The diagonal loading value is modified according to the formula: diagonal_loading_value = initial_diagonal_loading_value + adjustment_factor * SINR, where the adjustment factor controls the sensitivity to SINR changes. This parameter adaptation resolves the contradiction by optimizing both estimation accuracy and interference rejection capability simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the diagonal loading value is adjusted based on the estimated SINR from received signals. The system continuously monitors the signal quality, estimates SINR, and uses this information to adaptively adjust the diagonal loading parameter in the noise matrix estimation process. This closed-loop feedback ensures that the diagonal loading value remains optimal under varying channel conditions, resolving the contradiction between estimation accuracy and interference rejection.

Inventive Principle:
Principle #23Feedback

2Reliability

If the number of receiving antennas is increased to enhance interference rejection capability, then the receiving quality is improved, but the system complexity and computational burden increase

Engineering Contradiction:
Improveinterference rejection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces SINR-based adaptive diagonal loading as a parameter adjustment mechanism that optimizes the noise matrix estimation without requiring additional hardware. By dynamically adjusting the diagonal loading value based on SINR, the system achieves better interference rejection performance with the existing number of antennas, avoiding the need to increase antenna count and thereby reducing system complexity while maintaining improved reliability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3447983B1Diagonal loading method, device, and computer storage medium
Publication Date: 2023.04.19 ZTE CORP
  • EP3447983B1 patent drawingFigure 1
  • EP3447983B1 patent drawingFigure 2
  • EP3447983B1 patent drawingFigure 3

AI summary

Disclosed in embodiments of the present invention is a diagonal loading method. The method comprises: determining, according to a received pilot signal, a noise vector; determining, according to the noise vector, a noise matrix; determining, according to a noise power and interference power of a user location, a diagonal loading coefficient; and determining, according to the diagonal loading coefficient and the noise matrix, a diagonally loaded noise matrix, and performing equalization by means of the diagonally loaded noise matrix. Also disclosed in the embodiments of the present invention are a diagonal loading device and computer storage medium.