Terminal Device Feedback Codebook Determination for NR-U

The patent introduces dynamic determination of feedback timing by allowing the terminal to flexibly select from multiple candidate feedback timing values based on the trigger signaling and downlink channel reception status. This dynamic approach replaces the static Rel-15 scheme, enabling adaptation to infinite HARQ timing values while maintaining manageable complexity through predefined candidate sets and selection criteria.

The patent implements a feedback mechanism where the network sends trigger signaling to the terminal, which then determines the feedback information codebook based on this external trigger. The terminal autonomously generates the codebook content but the triggering and timing are controlled by network feedback, eliminating redundant information transmission while maintaining terminal autonomy in codebook construction. This resolves the ambiguity by establishing a clear trigger-based activation mechanism.

The patent makes the PUCCH resource indication information field in DCI serve multiple functions: it indicates both the PUCCH resource and the channel group information when the feedback timing field contains a predetermined value. This multi-functionality approach increases channel group identification accuracy without adding separate dedicated fields, thereby limiting the increase in DCI structure complexity while achieving precise feedback direction.