Terminal Apparatus HARQ-ACK Feedback Coordination via Segmented NFI Fields
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Solution Overview
Problem
Current communication systems, particularly in the context of LTE and emerging New Radio (NR) standards, face challenges in efficiently managing and coordinating HARQ-ACK feedback for multiple PDSCH groups across different DCI formats, leading to complexities in monitoring occasions and resource allocation.
Innovation Solution
The solution involves a terminal apparatus and base station apparatus configuration that allows for the reception and transmission of HARQ-ACK information based on distinct New Feedback Indicator (NFI) fields in different DCI formats, with parameter M being set to zero or corresponding to the number of monitoring occasions for PDCCH, enabling efficient coordination of HARQ-ACK feedback across multiple PDSCH groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If HARQ-ACK feedback is managed for multiple PDSCH groups across different DCI formats using a single NFI field, then the feedback process becomes simpler, but ambiguity arises in determining which PDSCH group the NFI applies to
Solution Approach 1:
The patent segments the NFI field into separate instances for different DCI formats. Specifically, a first NFI field is used for DCI format 1_0 and a second NFI field is used for DCI format 1_1. This segmentation eliminates ambiguity by clearly associating each NFI field with its corresponding DCI format and PDSCH group, while keeping the feedback management process straightforward through this clear separation.
2Reliability
If parameter M is set to the number of monitoring occasions for PDCCH, then HARQ-ACK feedback coverage is maximized, but the complexity of coordinating feedback across multiple PDSCH groups increases
Solution Approach 1:
The patent divides the monitoring occasions into separate sets for different DCI formats. The first set of monitoring occasions is associated with DCI format 1_0 and the second set with DCI format 1_1. By setting parameter M to the number of monitoring occasions in each respective set, the patent achieves comprehensive feedback coverage for each format while reducing coordination complexity through this clear separation of monitoring responsibilities.
3Loss of information
If separate NFI fields are used for different DCI formats, then ambiguity in NFI applicability is eliminated, but the downlink control information overhead increases
Solution Approach 1:
The patent applies local quality by making the NFI field structure adaptive to the specific DCI format being used. DCI format 1_0 includes a first NFI field specifically for its associated PDSCH group, while DCI format 1_1 includes a second NFI field for its PDSCH group. This localized approach ensures clear applicability of each NFI field to its corresponding format while minimizing overall overhead by not imposing additional NFI fields on formats that don't require them.
Data Source
AI summary
A terminal apparatus includes: a reception unit configured to receive indication of a first PDSCH group index in a first DCI format, and receive indication of a second PDSCH group index in a second DCI format; and a transmission unit configured to, in a case that the first DCI format is detected, transmit HARQ-ACK information of the second PDSCH group index, the HARQ-ACK information being determined based at least on a parameter M. A value of a first NFI of the second PDSCH group index is indicated by a first NFI field in the second DCI format. A value of a second NFI of the second PDSCH group index is indicated by a second NFI field in the first DCI format. In a case that the value of the second NFI is not null and the value of the second NFI is different from the value of the first NFI, a value of the parameter M is set to zero.