MU-MIMO Scheduling SINR Prediction Link Adaptation

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Solution Overview

Problem

Current MU-MIMO scheduling in LTE networks experiences abrupt Signal to Interference and Noise Ratio (SINR) variations due to non-ideal pairing of UEs, leading to performance degradation and inefficient power control, which cannot be quickly adapted by existing methods.

Innovation Solution

A method and radio base station configuration that predicts SINR values for UEs during pairing and de-pairing, allowing for improved link adaptation and power control adjustments to minimize interference and optimize transport formats, using pre-defined coefficients and power adaptation parameters to quickly adjust transmission power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If MU-MIMO scheduling is implemented to increase system throughput, then productivity is improved, but SINR stability deteriorates due to abrupt variations when UEs are paired or de-paired

Engineering Contradiction:

Improvesystem throughputVSAvoidSINR stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The system performs preliminary actions by predicting SINR values before actual MU-MIMO pairing occurs. The network node predicts what the SINR would be for each UE if paired with another UE, and uses these predictions to determine transport formats in advance, preventing abrupt SINR variations when pairing actually happens.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by using predicted SINR values to adjust transport formats before pairing occurs. The network node continuously monitors and adjusts the transport format based on predicted SINR, creating a feedback loop that maintains SINR stability while enabling MU-MIMO scheduling.

Inventive Principle:

Principle #23Feedback

2Device complexity

If power control step size is limited to [-1, 0, 1, 3] dB, then device complexity is reduced, but adaptability to abrupt SINR variations deteriorates

Engineering Contradiction:

Improvepower control complexityVSAvoidSINR adaptation speed

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary adaptation by predicting SINR values and determining appropriate transport formats before MU-MIMO pairing occurs. This allows the system to prepare power control adjustments in advance, avoiding the need for large reactive power control steps that would increase complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system skips the intermediate steps of reactive power control by directly predicting the required transport format based on predicted SINR. This allows the system to rush through the adaptation process in a single step rather than requiring multiple incremental power control adjustments.

Inventive Principle:

Principle #21Skipping (Rushing through)

Data Source

PatentEP2870814B1Methods and nodes for multiple user MIMO scheduling

Publication Date: 2018.03.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

The present invention relates to an RBS of a wireless network and to a method in the RBS for link adaptation at MU-MIMO scheduling. The method comprises scheduling (410) a first UE in pair with a second UE, and predicting (420) a signal to noise and interference value for each of the first and second UE as paired. The method also comprises using (430) the predicted signal to noise and interference values for performing link adaptation for the first and second UE.