PDSCH ACK-NACK Bundling Using DAI for Missing Grant Alignment
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Solution Overview
Problem
In wireless communication systems, particularly in New Radio (NR), the handling of multi-PDSCH grants leads to misalignment between base stations and user equipment (UE) regarding ACK-NACK reporting, resulting in increased control overhead and inefficiencies due to undefined parameters like PDSCH-to-HARQ feedback timing, PUCCH resource indicators, and downlink assignment indicators.
Innovation Solution
Implementing a counter DAI and total DAI mechanism at the UE to track multi-PDSCH grants, along with ACK-NACK bundling and virtual DCI association, to align reporting and reduce signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-PDSCH grants are implemented without DAI mechanism, then scheduling flexibility is improved, but misalignment between base station and UE occurs leading to increased control overhead
Solution Approach 1:
The patent implements a feedback mechanism using Downlink Assignment Indicators (DAI) that provide counting information from the base station to the UE. The counter DAI and total DAI work together to enable the UE to accurately track and report ACK-NACK status for multiple PDSCH grants, preventing misalignment and reducing unnecessary control overhead while preserving scheduling flexibility.
Solution Approach 2:
The DAI mechanism acts as an intermediary between the base station's scheduling decisions and the UE's ACK-NACK reporting. By introducing counter DAI and total DAI as intermediate signaling elements, the patent enables indirect coordination that resolves the alignment problem without requiring direct complex interaction, thus reducing control overhead while maintaining flexibility.
2Measurement precision
If ACK-NACK reporting is performed for each PDSCH individually, then reporting accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent combines multiple ACK-NACK reports into a single bundled report by implementing counter DAI and total DAI mechanisms. The counter DAI tracks individual PDSCH assignments while the total DAI provides overall counting information, enabling the UE to bundle multiple acknowledgments into one efficient report that maintains accuracy for each individual PDSCH while reducing total signaling overhead.
3Device complexity
If PUCCH resource indicators are not defined for multi-PDSCH grants, then DCI format simplicity is improved, but resource allocation efficiency deteriorates
Solution Approach 1:
The patent implements a universal PUCCH resource indicator mechanism that works across multiple PDSCH grants within a single DCI format. By defining PRI fields that can indicate PUCCH resources for multiple downlink assignments, the system maintains DCI format simplicity while enabling efficient resource allocation for multi-PDSCH scheduling scenarios.
Data Source
AI summary
This disclosure provides systems, methods and apparatuses for using acknowledgement or negative acknowledgement (ACK-NACK) bundling when reporting from a user equipment (UE) a bundled ACK-NACK for a plurality of physical downlink shared channels (PDSCHs) associated with a PDSCH grant. A counter downlink assignment indicator (DAI) and a total DAI may be used to track PDSCH grants that are received at the UE. The UE may detect missing PDSCHs and report ACK-NACKs for the missing PDSCHs based on the counter DAI and the total DAI. A base station (BS) may transmit the PDSCH grant associated with the plurality of PDSCHs to the UE. The BS may receive, from the UE, the bundled ACK-NACK for the plurality of PDSCHs associated with the PDSCH grant.