HARQ Codebook Switching for Carrier Aggregation Feedback Overhead
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Solution Overview
Problem
Existing HARQ feedback mechanisms struggle to adapt to complex conditions involving varying numbers of Code Block Groups (CBGs) across different Component Carriers (CCs), leading to inefficient feedback overhead.
Innovation Solution
A method and apparatus for configuring HARQ codebook formats based on carrier aggregation information, switching between first and second formats to optimize feedback overhead, including grouping CCs with similar resource units and adjusting feedback interpretation based on service requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a unified HARQ codebook format is used for multiple Component Carriers, then the feedback mechanism is simple to implement, but the feedback overhead increases when the number of CBGs varies across CCs
Solution Approach 1:
The patent implements dynamic HARQ codebook format switching between Type1 and Type2 formats based on the actual CBG configuration across aggregated CCs. The network device determines which format to use according to whether the total CBG count exceeds a threshold, allowing the system to adapt its feedback structure to varying transmission conditions rather than using a fixed format.
Solution Approach 2:
The patent changes the structural parameters of the HARQ codebook by switching between two distinct formats: Type1 uses a unified codebook structure suitable for fewer CBGs, while Type2 uses a segmented codebook structure for larger CBG counts. This parameter change optimizes the feedback overhead by matching the codebook structure to the actual data volume and distribution across CCs.
2Loss of time
If HARQ feedback is optimized for delay-sensitive services like URLLC, then transmission timeliness improves, but the system becomes less adaptable to diverse service requirements
Solution Approach 1:
The patent creates a universal HARQ feedback mechanism that can handle multiple service types (eMBB, mMTC, URLLC) through a single unified framework. By supporting both Type1 and Type2 codebook formats and allowing flexible CBG aggregation across CCs, the system can adapt to different service requirements without needing separate feedback mechanisms for each service type.
Solution Approach 2:
The patent segments the HARQ feedback approach into two distinct codebook formats (Type1 and Type2) that can be selectively applied based on service requirements and CBG configuration. This segmentation allows the system to use the more compact Type1 format when appropriate for faster feedback, while using Type2 when dealing with larger CBG counts, thus balancing timeliness and adaptability.
3Productivity
If CBG-level retransmission is implemented instead of TB-level retransmission, then retransmission efficiency improves, but the feedback overhead increases due to finer granularity
Solution Approach 1:
The patent merges multiple CBGs from different Component Carriers into a unified or segmented codebook structure depending on the total CBG count. By aggregating CBG-level feedback across multiple CCs into a single HARQ feedback message (using either Type1 unified format or Type2 segmented format), the system achieves fine-grained retransmission control without proportionally increasing feedback overhead, as the feedback is consolidated rather than sent separately for each CBG.
Data Source
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AI summary
Provided are a Hybrid Automatic Repeat reQuest (HARQ) feedback configuration method and device, a method and device for determining data to be retransmitted, a data receiving apparatus, a data sending apparatus and a computer-readable storage medium. The HARQ feedback configuration method includes: configuring HARQ codebook switching information for a data sender according to carrier aggregation information; and sending the HARQ codebook switching information the data sender. According to the embodiments of the present disclosure, the HARQ codebook switching information is configured for the data sender according to the carrier aggregation information for adaptation to a complex condition, and the HARQ codebook switching information is sent to the data sender, so that the data sender may accordingly determine resource unit information of data to be retransmitted.