Sidelink HARQ-ACK Codebook Selection in NR Terminals
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Solution Overview
Problem
In NR sidelink communication, it is unclear which HARQ-ACK codebook to use when multiple codebooks are configured for reporting HARQ-ACK bits to a base station in direct terminal communication.
Innovation Solution
A terminal is equipped with a receiving unit to specify codebooks for retransmission control, a controlling unit to determine the appropriate codebook for sidelink communication, and a transmitting unit to report HARQ-ACKs to the base station using the determined codebook.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple HARQ-ACK codebooks are configured for downlink transmission, then the system can support multiple downlink carriers or services, but it becomes unclear which codebook the terminal should use for sidelink HARQ-ACK reporting
Solution Approach 1:
The patent segments the codebook selection process by introducing specific indication mechanisms (PUCCH resource indication, DCI fields, or RRC configuration parameters) that divide the ambiguous codebook selection problem into distinct, identifiable codebook options. This allows the terminal to clearly identify which codebook to use for sidelink HARQ-ACK reporting among multiple configured codebooks.
Solution Approach 2:
The patent introduces an intermediary indication mechanism (such as PUCCH resource indication or DCI fields) that mediates between the base station's codebook configuration and the terminal's codebook selection. This intermediary provides explicit guidance to the terminal, resolving the ambiguity of which codebook to use for sidelink reporting.
2Productivity
If HARQ-ACK bits from multiple sidelinks are multiplexed, then traffic efficiency is improved, but the complexity of codebook management increases
Solution Approach 1:
The patent merges multiple sidelink HARQ-ACK bits into a single codebook structure for multiplexed reporting. By combining the HARQ-ACK information from multiple sidelinks into one unified codebook, the system improves traffic efficiency while the indication mechanism manages the complexity of codebook selection.
3Ease of operation
If explicit codebook indication mechanisms are introduced, then codebook selection clarity is improved, but signaling overhead increases
Solution Approach 1:
The patent applies local quality by introducing codebook indication only where needed (in specific DCI fields or PUCCH resource configurations) rather than universally throughout all signaling. This provides necessary codebook selection clarity while minimizing unnecessary signaling overhead in other parts of the system.
Data Source
AI summary
A terminal includes a receiving unit configured to receive, from a base station, one or more pieces of information specifying a plurality of codebooks for transmitting a response related to retransmission control to be applied to transmission and reception in a downlink; a controlling unit configured to determine which codebook among the plurality of codebooks is a codebook for transmitting a response related to retransmission control to be applied to transmission and reception in a sidelink; and a transmitting unit configured to transmit to the base station, by using the determined codebook, one or more responses related to retransmission control to be applied to transmission and reception in the sidelink.