Soft ACK-NACK CSI Codebook for Missed DCI Trigger Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In wireless communication systems, user equipment (UE) may miss downlink control information (DCI) with CSI triggers, leading to incorrect A-CSI reporting and payload size mismatches, which can hinder decoding by the base station.

Innovation Solution

The UE is designed to detect missed DCIs with CSI triggers and provide A-CSI reporting in a soft A/N payload, using techniques such as fixed-size A-CSI reporting, joint encoding, or additional DAI bits to ensure accurate payload size determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the UE uses variable-size A-CSI reporting based on received DCIs, then the reporting efficiency is improved, but the base station cannot correctly decode the payload when DCIs are missed

Engineering Contradiction:

Improvereporting efficiencyVSAvoidpayload decoding accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by having the UE detect and report missed DCIs with CSI triggers before the base station can correctly decode the payload. The UE uses counter increments in the soft A/N payload to pre-indicate the presence of A-CSI bits, allowing the base station to correctly interpret the payload size and structure even when DCIs are missed, thus resolving the contradiction between reporting efficiency and decoding accuracy.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the UE transmits soft A/N payload with A-CSI bits, then the communication efficiency is improved, but the payload size becomes unpredictable causing decoding errors

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidpayload size prediction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by having the UE include counter information in the soft A/N payload that indicates the number of A-CSI bits transmitted. This feedback mechanism allows the base station to accurately determine the payload size and correctly decode the A/N information, resolving the contradiction between communication efficiency and payload size prediction accuracy.

Inventive Principle:

Principle #23Feedback

3Reliability

If the UE reports A-CSI based on detected missed DCIs, then the reliability of CSI reporting is improved, but the complexity of detecting and handling missed DCIs increases

Engineering Contradiction:

ImproveCSI reporting accuracyVSAvoidmissed DCI detection complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by having the UE autonomously detect missed DCIs and automatically adjust its reporting behavior without requiring complex external intervention. The UE uses counter increments and soft A/N payload mechanisms to self-correct for missed DCIs, maintaining CSI reporting accuracy while managing the complexity through standardized procedures.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP3871351B1Soft ACK-NACK with CSI codebook

Publication Date: 2026.01.28 QUALCOMM INC

Figure 1
Figure 2
Figure 3A

AI summary

Systems and methods for wireless communication include a user equipment (UE) and a base station, wherein the UE transmits additional channel state information (A-CSI), along with ACK/NACK (or "A/N") reporting to the base station in a soft A/N payload. The A/N reporting is responsive to downlink control information (DCI) grants in a downlink transmission from the base station. The A-CSI reporting is responsive one or more DCIs which include a CSI trigger. Even if one or more DCIs with CSI triggers are missed in the downlink transmission, the UE is designed to detect whether there may be any missing DCIs with CSI triggers and provide A-CSI reporting in the soft A/N payload based on this detection.