MU-MIMO SNR Estimation via Channel Orthogonality

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Solution Overview

Problem

Current MU-MIMO systems face high computational complexity in estimating Signal-to-Interference-and-Noise Ratio (SINR) due to the need for precoding and post-coding weights for multiple user combinations, which hinders efficient user pairing and performance enhancement in wireless networks.

Innovation Solution

A method is proposed to estimate MU-MIMO SINR based on channel orthogonality and SU-MIMO signal quality measurements, reducing computational complexity by using orthogonality factors and correlation coefficients to evaluate user pairing alternatives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods for SINR estimation are used in MU-MIMO, then accurate signal quality measurement can be obtained, but computational complexity becomes excessively high due to the need for precoding and post-coding weights for all possible user combinations

Engineering Contradiction:
ImproveSINR estimation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential information needed for SINR estimation from the full MU-MIMO system by using SU-MIMO signal quality measurements and channel orthogonality indicators. Instead of computing complete precoding/post-coding weights for all user combinations, the method extracts only the necessary orthogonality factors between user channels, significantly reducing computational requirements while maintaining estimation accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses SU-MIMO signal quality measurements as a simplified copy or approximation of the more complex MU-MIMO SINR estimation. By measuring signal quality in a simpler SU-MIMO configuration and combining this with channel orthogonality information, the method obtains sufficient SINR estimates without performing the computationally intensive full MU-MIMO analysis.

Inventive Principle:
Principle #26Copying

2Productivity

If the number of active users is increased to improve network capacity, then spectrum usage and throughput can be enhanced, but the number of possible user pairing combinations increases exponentially

Engineering Contradiction:
Improvespectrum usage and throughputVSAvoiduser pairing evaluation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the user pairing evaluation process by independently evaluating orthogonality between individual user pairs rather than analyzing all possible combinations simultaneously. This segmentation allows the system to handle a larger number of active users by breaking down the complex pairing evaluation into simpler, independent orthogonality assessments between user pairs.

Inventive Principle:
Principle #1Segmentation

3Reliability

If user pairing algorithms evaluate all possible combinations to maximize joint channel capacity, then optimal user selection can be achieved, but the evaluation process becomes computationally intensive and slow

Engineering Contradiction:
Improveoptimal user pairing selectionVSAvoiduser pairing evaluation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical/computational process of calculating complete precoding weights and evaluating all user combinations with a more efficient approach based on channel orthogonality indicators. This substitution maintains the ability to identify optimal user pairings while dramatically increasing evaluation speed by using simpler orthogonality metrics instead of full system analysis.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11411632B2Method to estimate SNR for MU-MIMO based on channel orthogonality
Publication Date: 2022.08.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US11411632B2 patent drawing
  • US11411632B2 patent drawing
  • US11411632B2 patent drawing

AI summary

Systems and methods for estimating Signal-to-Noise Ratio (SNR) for Multi-User Multiple-Input and Multiple-Output (MU-MIMO) based on channel orthogonality. In some embodiments, a method performed by a radio access node includes obtaining a SU-MIMO signal quality measurement for at least a first user and an additional user; obtaining an indication of orthogonality between a channel of the first user and a channel of the additional user; and estimating a MU-MIMO signal quality measurement for the first user as if the first user and the additional user are paired with each other for a potential MU-MIMO transmission based on the SU-MIMO signal quality measurements and the indication of orthogonality. In this way, a computational complexity for the SINR estimation of MU-MIMO users can be greatly reduced. This may enable a large number of user pairing alternatives to be evaluated in practical wireless systems to achieve improved MU-MIMO performance.