Link Adaptation via Channel Quality Distribution Estimation

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Solution Overview

Problem

Traditional link adaptation methods in wireless communication networks face challenges in efficiently managing channel quality due to rapid changes caused by interference from neighboring cells, leading to poor convergence speed and increased estimation errors, especially when considering flash light effects and burst characteristics in real traffic volumes.

Innovation Solution

A method that estimates the distribution of channel quality values rather than tracing individual channel quality values, allowing for the optimization of transmission parameters to maximize expected throughput by mapping sets of transmission parameters to required channel qualities for successful reception, using techniques such as Gaussian mixture models and histogram methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional link adaptation methods trace individual channel quality values, then the system can maintain simplicity in implementation, but the convergence speed deteriorates and estimation errors increase due to rapid channel changes and interference

Engineering Contradiction:
Improveimplementation complexityVSAvoidchannel quality estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms the approach from tracking individual channel quality values to estimating the statistical distribution parameters (mean and variance) of channel quality. This parameter transformation allows the system to capture channel behavior characteristics without being affected by rapid fluctuations, thereby improving estimation accuracy while maintaining computational efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of directly tracking the complex and rapidly changing individual channel quality values, the patent creates a statistical representation (distribution model) that copies the essential characteristics of channel behavior. This statistical copy is more stable and easier to process, resolving the contradiction between simplicity and accuracy.

Inventive Principle:
Principle #26Copying

2Stability of the object's composition

If traditional methods use outer loop adjustments for link adaptation, then the system can maintain a fixed structure, but confidence range issues arise and convergence becomes slow due to burst characteristics in real traffic

Engineering Contradiction:
Improvesystem structure stabilityVSAvoidconvergence speed
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent introduces dynamic adaptation by continuously estimating distribution parameters from incoming channel quality measurements and adjusting transmission parameters accordingly. This dynamic approach replaces the static outer loop adjustment mechanism, enabling faster convergence while adapting to burst characteristics in real traffic without requiring complex structural changes.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the system considers flash light effects from neighboring cells, then the robustness against interference improves, but the complexity of channel quality tracking increases significantly

Engineering Contradiction:
Improveinterference resistanceVSAvoidchannel quality tracking complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential statistical characteristics (distribution mean and variance) from the complex channel quality data, discarding the detailed temporal variations caused by flash light effects. This extraction approach maintains robustness against interference while significantly reducing tracking complexity by focusing on the stable statistical properties rather than instantaneous values.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS11296817B2Method and network node, for handling link adaption of a channel
Publication Date: 2022.04.05 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US11296817B2 patent drawing
  • US11296817B2 patent drawing
  • US11296817B2 patent drawing

AI summary

A method performed by a network node, for handling link adaption (LA) of a channel. The network node obtains a channel quality value for each Transmission Time Interval (TTI) in a set of TTIs. The network node estimates a probability that a specific channel quality will occur from the obtained channel quality values for the set of TTIs based on a distribution of channel quality values. The network node further determines a set of transmission parameters which optimizes a target function of LA, based on the estimated probability for the channel quality, wherein each set of transmission parameters is mapped to a channel quality which is required for a successful reception.