HARQ-ACK Codebook Prioritization Across Multi-Cell Feedback
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in managing Hybrid Automatic Repeat reQuest (HARQ) processes across cells with varying priorities, leading to suboptimal wireless signal transmission and reception.
Innovation Solution
A method and apparatus for configuring HARQ-ACK feedback based on cell and process indices, where HARQ-ACK information for cells with lower priority is excluded from the codebook when indicated by Downlink Control Information (DCI), optimizing transmission and reception procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HARQ-ACK feedback for all cells is included in the codebook, then complete feedback coverage is achieved, but transmission efficiency decreases due to inclusion of low-priority cell data
Solution Approach 1:
The patent extracts and excludes HARQ-ACK information for low-priority cells from the codebook when high-priority feedback is required. The DCI format includes a priority indicator that triggers selective exclusion of second cell (low-priority) HARQ-ACK information, keeping only first cell (high-priority) information in the codebook, thus improving transmission efficiency without losing critical feedback information
Solution Approach 2:
The patent implements dynamic configuration of the codebook content based on priority indicators in DCI. The codebook structure changes dynamically - sometimes including all cells, sometimes excluding low-priority cells - depending on the current transmission requirements indicated by the priority field in DCI, allowing flexible adaptation to different feedback scenarios
2Reliability
If HARQ-ACK codebook includes all cells regardless of priority, then feedback completeness is maintained, but processing complexity increases
Solution Approach 1:
The patent segments the HARQ-ACK codebook into high-priority and low-priority portions corresponding to different cells. The first cell contains high-priority HARQ processes while the second cell contains low-priority HARQ processes. This segmentation allows selective inclusion/exclusion of segments based on priority indicators, reducing processing complexity when only high-priority feedback is needed
Solution Approach 2:
The patent applies different quality levels to different parts of the codebook by assigning priority levels to different cells. The first cell is designated with first priority while the second cell is designated with second priority. This local quality differentiation enables the system to focus processing resources on high-priority portions while optionally excluding low-priority portions, reducing overall processing complexity
3Productivity
If priority-based exclusion of HARQ-ACK information is implemented, then transmission efficiency improves, but system complexity increases due to priority management
Solution Approach 1:
The patent implements a universal priority indicator mechanism in DCI that can trigger priority-based exclusion across multiple cells and HARQ processes. This single priority indicator field in the DCI format provides multi-functional control - it can indicate whether to include or exclude low-priority cell feedback, and this mechanism works universally across different cell configurations and HARQ process numbers, managing complexity through a standardized approach
Solution Approach 2:
The patent changes the parameter of codebook composition based on the priority indicator parameter in DCI. When the priority indicator signifies high-priority transmission, the codebook parameter is changed to exclude low-priority cell information. This parameter-based control mechanism automates the priority management process, reducing manual configuration complexity while maintaining transmission efficiency
Data Source
AI summary
The present disclosure relates to a wireless communication system, and specifically to a method and a device therefor, the method comprising: a step for receiving configuration information about a plurality of cells comprising (i) a first cell having a first HARQ process index and operable with a first priority, and (ii) a second cell having only a second HARQ process index and operating only with a second priority lower than the first priority; a step for receiving an HARQ-ACK feedback request via DCI; and a step for transmitting an HARQ-ACK codebook for the plurality of cells on the basis of the HARQ-ACK feedback request, wherein HARQ-ACK information in the HARQ-ACK codebook is in descending order of first cell index and then HARQ process index, and the HARQ-ACK information about the second cell is excluded from the HARQ-ACK codebook on the basis that the first priority is indicated by the DCI.