HARQ-ACK Codebook Arrangement for Multiple SPS Configurations
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Solution Overview
Problem
In next-generation mobile communication systems, particularly in New Radio (NR), the existing specifications do not clearly define how to configure the HARQ-ACK codebook for multiple Semi-Persistent Scheduling (SPS) configurations, leading to inadequate HARQ control and potentially deteriorated communication throughput when multiple SPSs are used.
Innovation Solution
The proposed solution involves determining the codebook size and arrangement order of HARQ-ACK bits for multiple SPS PDSCHs based on active SPS configurations and HARQ timing values, using rules such as earlier SPS occasion, lower CC index, and lower SPS index to ensure appropriate feedback even in cases with multiple SPS configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple SPS configurations are used to increase data rates and capacity, then communication throughput is improved, but HARQ control reliability deteriorates due to unclear codebook configuration specifications
Solution Approach 1:
The patent changes the arrangement parameters of HARQ-ACK bits in the codebook by introducing a specific ordering rule based on SPS occasion indices. When multiple SPS configurations are used, HARQ-ACK bits are arranged in increasing order of candidate PDSCH reception occasion indices, with ties broken by serving cell indices. This parameter change in bit arrangement resolves the ambiguity in codebook configuration while maintaining support for multiple SPS configurations, thus improving reliability without sacrificing throughput
Solution Approach 2:
The patent segments the HARQ-ACK codebook arrangement process into hierarchical levels: first grouping by SPS occasion indices, then by serving cell indices. This segmentation approach allows the system to handle multiple SPS configurations systematically by dividing the complex arrangement problem into manageable segments, ensuring each HARQ-ACK bit has a deterministic position in the codebook while supporting high throughput scenarios with multiple active SPS configurations
2Productivity
If multiple SPS configurations are activated to increase system capacity, then data rate is improved, but codebook configuration complexity increases leading to potential misalignment between UE and base station
Solution Approach 1:
The patent simplifies the codebook configuration by changing the arrangement parameter from an undefined structure to a deterministic ordering based on SPS occasion indices and serving cell indices. This parameter change reduces configuration complexity by providing a clear, rule-based arrangement method that both UE and base station can independently apply, eliminating misalignment issues even when multiple SPS configurations are activated to increase system capacity
Solution Approach 2:
The patent enables self-service in codebook configuration by establishing a deterministic arrangement rule that allows both UE and base station to independently construct the same HARQ-ACK codebook structure without complex coordination. The systematic ordering by SPS occasion indices and serving cell indices allows each device to autonomously determine bit positions, reducing configuration complexity and eliminating alignment issues in multi-SPS scenarios
Data Source
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Figure 3A~3B
AI summary
A terminal according to an aspect of the present disclosure includes: a control section that determines a size of a semi-static hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook including HARQ-ACK corresponding to a downlink shared channel (physical downlink shared channel (PDSCH)) of semi-persistent scheduling (SPS) based on the number of configured SPS configurations, the number of configured or activated cells, and the number of HARQ-ACK timing values included in a set of the configured HARQ-ACK timing values; and a transmitting section that transmits an HARQ-ACK information bit corresponding to the HARQ-ACK codebook by using a resource of an uplink control channel. According to one aspect of the present disclosure, the HARQ-ACK can be appropriately feed back even in a case where multiple SPSs are used.