HARQ-ACK Codebook Determination for Fallback DCI Scheduling

The patent introduces an intermediary mechanism where the UE determines GI and NFI values based on the DCI format type and received indicators rather than directly extracting them from the DCI fields. For fallback DCI, the UE uses predefined GI values and NFI determination methods that involve comparing with previous DCI formats, thus mediating the information loss to enable HARQ-ACK codebook determination.

The patent changes the parameter determination approach by using different GI and NFI determination methods based on DCI format. For fallback DCI format 1_0, the UE applies specific parameter rules (e.g., using predefined GI values and alternative NFI determination through indicator comparison) rather than direct field extraction, allowing the system to adapt to the simplified DCI structure while maintaining functionality.

The patent segments the HARQ-ACK codebook determination process into distinct steps: identifying the DCI format type, determining the PDSCH group index based on DCI indicators, and determining whether new feedback is required. This segmentation allows the UE to handle the complexity systematically by processing each aspect separately based on the received indicators.

The patent implements dynamic determination of GI and NFI values based on the actual DCI format received. The UE dynamically adjusts its determination method depending on whether the DCI is fallback format 1_0 or enhanced format 1_1, allowing the system to adapt the complexity level to the specific DCI type while maintaining efficient HARQ-ACK management.