Dynamic Type-3 HARQ-ACK Codebook Selection for URLLC

The patent implements dynamic codebook size adjustment by introducing multiple enhanced type-3 HARQ-ACK codebooks with different sizes. The UE can dynamically select the appropriate codebook size based on the actual scheduling situation and number of active cells, rather than being constrained to a fixed codebook structure. This dynamic adaptation resolves the contradiction between maintaining simple standardized feedback and achieving flexible codebook size reduction.

The patent changes the parameter of codebook size by defining multiple enhanced type-3 HARQ-ACK codebooks with different bit lengths. The DCI format includes a codebook indication field that signals which codebook size should be used, allowing the system to adjust the codebook parameter according to traffic conditions and active cell configurations, thereby achieving flexible size adaptation while maintaining operational simplicity.

The patent applies local quality by allowing different codebook sizes to be used for different scheduling scenarios and active cell configurations. Instead of uniformly reporting for all cells regardless of activity status, the system locally adapts the codebook size to match the actual number of active cells and scheduled transmissions, thereby reducing reporting overhead while maintaining complete feedback coverage for all relevant cells.

The patent implements partial action by enabling the UE to report HARQ-ACK feedback only for the necessary subset of cells and transmissions rather than always reporting for all cells in the cell group. By using smaller codebook sizes when appropriate, the system performs the minimum necessary feedback action required for reliability, avoiding excessive reporting overhead while maintaining complete coverage for all scheduled and active cells.

The patent introduces dynamic codebook size selection through multiple enhanced type-3 HARQ-ACK codebooks, allowing the system to adapt the codebook size to the actual feedback volume requirements of URLLC services. This dynamic approach maintains implementation simplicity through standardized procedures while significantly improving resource usage efficiency by matching codebook size to the variant feedback volumes characteristic of URLLC traffic patterns.

The patent changes the codebook size parameter based on the specific service requirements and feedback volume characteristics. For URLLC services with small and variant feedback volumes, the system can select smaller codebook sizes from the available options, thereby improving resource usage efficiency without sacrificing implementation simplicity, as the selection process follows standardized procedures defined in the specification.