HARQ Codebook Determination for BWP Change Scenarios
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Solution Overview
Problem
Current Hybrid Automatic Repeat Request (HARQ) codebook determination procedures in wireless communication systems are inefficient, particularly in scenarios involving active UL BWP changes, leading to unnecessary transmissions and increased latency due to the inclusion of irrelevant HARQ information in the codebook.
Innovation Solution
A User Equipment (UE) determines whether to include HARQ information in the codebook based on whether the cell associated with the active UL BWP change is the same as the cell used for transmitting the HARQ codebook, optimizing the codebook generation to exclude irrelevant occasions and reduce unnecessary transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE includes all HARQ information in the codebook regardless of active UL BWP changes, then the codebook is complete and reliable, but the codebook size increases and causes unnecessary transmissions
Solution Approach 1:
The patent extracts and removes irrelevant HARQ information from the codebook by identifying occasions where the active UL BWP changed before the occasion but the transmitting cell is different from the cell where the BWP change occurred. This extraction principle eliminates unnecessary HARQ entries while preserving those that are actually needed, resolving the contradiction between codebook completeness and size reduction.
Solution Approach 2:
Instead of including all possible HARQ information (excessive action), the patent applies partial action by selectively including only those HARQ entries that are relevant to the current active UL BWP configuration. This partial inclusion approach maintains sufficient reliability for actual transmissions while avoiding the overhead of including redundant HARQ information.
2Reliability
If the UE includes irrelevant HARQ information in the codebook, then the codebook is comprehensive, but transmission latency increases due to unnecessary transmissions
Solution Approach 1:
The patent extracts irrelevant HARQ information from the codebook by applying a filtering criterion: if an active UL BWP change occurred before a HARQ occasion and the transmitting cell differs from the cell where the BWP change occurred, that HARQ entry is excluded. This extraction eliminates unnecessary transmissions and reduces the time required for codebook processing and transmission.
3Productivity
If the UE optimizes the HARQ codebook by excluding irrelevant occasions, then transmission efficiency improves, but the complexity of codebook determination increases
Solution Approach 1:
The patent applies preliminary action by determining whether an active UL BWP change occurred before each HARQ occasion in advance of codebook construction. This preliminary identification of BWP change events allows the UE to pre-filter irrelevant HARQ entries, simplifying the subsequent codebook assembly process while maintaining high transmission efficiency.
Solution Approach 2:
The patent segments the HARQ codebook determination process into distinct steps: first identifying active UL BWP changes, then determining which cells are affected, and finally filtering HARQ entries based on the relationship between BWP change cells and transmitting cells. This segmentation makes the complex determination process more manageable and systematic.
Data Source
AI summary
In an example, a User Equipment (UE) is configured with one or more first Physical Uplink Control Channel (PUCCH) resources on a primary cell (PCell) and configured with one or more second PUCCH resources on a secondary cell (SCell). The PCell and the SCell are associated with a PUCCH group. Before a first slot, the UE changes an active uplink (UL) bandwidth part (BWP) of a cell. The cell associated with the changing the active UL BWP is the PCell or the SCell. A first occasion of the PCell is before the changing the active UL BWP. A second occasion of the SCell is before the changing the active UL BWP. The first occasion and the second occasion are associated with the first slot. The UE determines whether or not to include Hybrid Automatic Repeat request (HARQ) information, associated with the second occasion, in a HARQ codebook based on whether or not the SCell, associated with transmitting the HARQ codebook, is the same as the cell associated with the changing the active UL BWP. The UE transmits, in the first slot and on the SCell, a PUCCH including the HARQ codebook.