Link Adaptation for Dynamic TDD Interference Management

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Dynamic TDD configurations in cellular networks lead to inaccurate radio channel quality measurement and estimation due to interference from neighboring cells with different uplink and downlink subframe configurations, resulting in suboptimal link adaptation and performance deterioration.

Innovation Solution

Implementing a method for link adaptation that involves determining interference from neighboring cells' subframes and applying specific link adaptation loops based on interference thresholds, using SINR compensation factors and CRC check results to adjust Modulation and Coding Schemes (MCS) in uplink and downlink subframes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dynamic TDD configurations are used to improve system performance in hot spot and indoor scenarios, then adaptability is improved, but measurement precision deteriorates due to interference from neighboring cells with different uplink and downlink subframe configurations

Engineering Contradiction:

Improvedynamic TDD configuration adaptabilityVSAvoidradio channel quality measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the link adaptation process into two distinct loops: a first link adaptation loop for uplink subframes and a second link adaptation loop for downlink subframes. Each loop independently determines interference conditions and applies appropriate SINR compensation factors, preventing interference from one subframe type from affecting the other and thus maintaining measurement precision while preserving dynamic TDD adaptability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different quality adjustment strategies to different parts of the system based on local interference conditions. By identifying whether specific uplink or downlink subframes experience interference and applying targeted SINR compensation only where needed, the system maintains accurate channel quality measurements in non-interfered subframes while correcting measurements in interfered subframes

Inventive Principle:

Principle #3Local quality

2Productivity

If link adaptation uses measured SINR to select MCS, then productivity is improved, but reliability deteriorates when interference causes inaccurate SINR measurement

Engineering Contradiction:

Improvedata transmission throughputVSAvoidMCS selection accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary interference determination before MCS selection by checking whether uplink or downlink subframes experience interference from neighboring cells. Based on this preliminary assessment, the system pre-calculates appropriate SINR compensation factors and selects different link adaptation loops, ensuring that accurate SINR values are obtained before MCS selection to maintain both productivity and reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the system monitors interference conditions and adjusts SINR compensation factors accordingly. By continuously determining whether interference exists and adjusting the link adaptation approach based on this feedback, the system ensures accurate MCS selection even in dynamic interference environments, maintaining both throughput and reliability

Inventive Principle:

Principle #23Feedback

3Device complexity

If a single link adaptation loop is used for all subframes, then device complexity is reduced, but measurement precision deteriorates due to interference from neighboring cells with different subframe configurations

Engineering Contradiction:

Improvelink adaptation structure complexityVSAvoidchannel quality estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces dynamic selection of link adaptation loops based on real-time interference conditions. Rather than using a fixed single loop or a always-complex multi-loop structure, the system dynamically determines which loop to use for each subframe based on whether interference is present, achieving measurement precision comparable to multiple loops while maintaining lower average complexity through conditional logic

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10277358B2Methods for performing link adaptation and related base stations

Publication Date: 2019.04.30 SAGO STRATEGIC SOLUTIONS LLC

AI summary

The present disclosure relates to a link adaptation scheme. In one embodiment, there provides a method for performing link adaptation in an uplink subframe for a first cell, the method comprising: obtaining interference to the uplink subframe of the first cell from at least one neighboring cell's downlink subframe occupying a time interval same as the uplink subframe; determining whether the obtained interference exceeds a predetermined threshold; and applying to the uplink subframe a first link adaptation loop when the obtained interference exceeds the predetermined threshold.