HARQ-ACK Codebook Signaling for Variable 5G Feedback Delays

The HARQ-ACK codebook is segmented into multiple sub-codebooks, where each sub-codebook corresponds to a specific downlink time unit. This segmentation allows the receiving end to determine and feedback HARQ-ACK information for different time units separately, managing the complexity of variable delay feedback by dividing it into manageable segments.

The patent implements dynamic determination of HARQ-ACK codebook size and structure based on received control signaling. The receiving end dynamically adjusts the codebook configuration according to the actual scheduling conditions and variable delay requirements, allowing the system to adapt to different scheduling scenarios while maintaining manageable complexity through standardized determination procedures.

The patent employs preliminary indexing mechanisms (such as DAI - Downlink Assignment Index) that are included in the control signaling before HARQ-ACK feedback is required. These indices pre-indicate the codebook size and structure, allowing the receiving end to determine the codebook configuration in advance without complex real-time calculations, thus improving resource utilization while managing determination complexity.

Control signaling acts as an intermediary that carries index information and determination rules from the transmitting end to the receiving end. This intermediary mechanism simplifies the codebook determination process by providing standardized index-based rules, eliminating the need for complex negotiations or calculations between endpoints.

The patent divides downlink shared channels into multiple PDSCH groups, with each group potentially requiring different HARQ-ACK codebook types (such as Type-1 or Type-2 codebooks). By segmenting the feedback into group-specific sub-codebooks, the system achieves precise feedback for each group's specific requirements while managing overall signaling overhead through standardized group management mechanisms.

Different PDSCH groups can be assigned different codebook types based on their specific characteristics and requirements. This local quality approach allows each group to have optimized feedback accuracy suited to its particular needs, while the overall system maintains efficiency through the standardized framework for managing multiple groups with different properties.