Selective Sub-band CQI Reporting for URLLC Reliability

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently reporting channel quality indicators (CQIs) across multiple sub-bands, particularly in multi-port operations, which affects the selection of modulation and coding schemes (MCS) for ultra-reliable low-latency communications (URLLC).

Innovation Solution

The proposed solution involves a user equipment (UE) that measures CQIs across multiple sub-bands for each CSI-RS resource, selects the worst CQIs, and reports them to the base station. This allows the base station to select an appropriate MCS based on worst-case channel conditions, ensuring reliability for URLLC communications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE reports all CQI measurements across all sub-bands, then the base station can make accurate MCS selection decisions, but the reporting overhead and processing complexity increase significantly

Engineering Contradiction:

ImproveCQI measurement accuracyVSAvoidreporting complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the most critical CQI information for reporting. Specifically, it identifies and reports only the worst M sub-band CQIs out of all measured sub-bands, or selectively reports CQIs based on comparison with threshold values. This extraction principle reduces reporting overhead while maintaining sufficient accuracy for reliable MCS selection at the base station.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by treating different sub-bands differently based on their channel conditions. Instead of uniform reporting across all sub-bands, it selectively identifies and reports only those sub-bands with poor channel conditions (worst M sub-bands) or sub-bands that fail to meet quality thresholds. This localized approach focuses reporting resources on the most critical areas.

Inventive Principle:

Principle #3Local quality

2Productivity

If the UE reports only a subset of CQI measurements, then the reporting overhead is reduced, but the base station loses information needed for accurate MCS selection

Engineering Contradiction:

Improvereporting efficiencyVSAvoidCQI information loss

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent converts the potential harm of information loss into a benefit by strategically selecting which CQI measurements to report. Instead of reporting all CQIs (which would be inefficient), it reports specifically the worst M sub-band CQIs or those below thresholds. The base station uses this selective information, combined with knowledge of which sub-bands were reported, to make accurate MCS decisions that account for the worst-case channel conditions.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent performs preliminary selection of CQI measurements at the UE before reporting. The UE pre-identifies the worst M sub-bands or compares CQIs against thresholds and selects only those meeting reporting criteria. This preliminary action ensures that the most critical information is prioritized for reporting, enabling the base station to make accurate MCS decisions with reduced reporting overhead.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the system uses multi-port CSI-RS resources for CQI measurement, then the reliability of channel quality assessment improves, but the complexity of CQI selection and reporting increases

Engineering Contradiction:

Improvechannel quality assessment reliabilityVSAvoidCQI selection complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the CQI measurement process by treating each CSI-RS resource separately. For each CSI-RS resource, the UE independently measures CQIs across sub-bands, selects the worst M sub-band CQIs or those below thresholds, and prepares separate reports. This segmentation allows the system to leverage multiple ports for improved reliability while managing complexity through structured, resource-by-resource processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by not requiring full CQI reporting for all CSI-RS resources. Instead, the UE performs measurements on multiple CSI-RS resources for reliability, but selectively reports only the most critical CQI information (worst M sub-bands or threshold-failing CQIs) from each resource. This partial reporting approach maintains reliability benefits while controlling complexity.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12284135B2Selective sub-band channel quality indicator reporting

Publication Date: 2025.04.22 QUALCOMM INC

AI summary

A base station may transmit a set of CSI-RSs corresponding to a set of ports of a UE and the UE may perform a set of CQI measurements on each port and across each sub-band. The UE may select, for each CSI-RS resource that the UE measures, a set of M worst CQIs and may select a best CSI-RS resource based at least in part on a corresponding set of M worst CQIs for the CSI-RS resource. The UE may report the M worst CQIs for the selected CSI-RS resource. Alternatively, the UE may select, for each CSI-RS resource that the UE measures, a set of M worst CQIs and may select a worst CSI-RS resource. In this way, the UE enables the base station to select a DMRS port and/or an MCS to use for communication.