PUCCH Occasion Selection for Delayed HARQ-ACK Codebooks
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Solution Overview
Problem
In 5G NR systems, determining a valid PUCCH for delayed HARQ-ACK codebook is challenging when SPS periodicity is low, leading to imbalanced HARQ-ACK feedback and unreliable PUCCH transmission for ultra-reliable and low-latency communications due to collisions with downlink or flexible symbols.
Innovation Solution
A method for determining a valid PUCCH occasion by selecting PUCCH resources from preconfigured sets based on condition settings, including using only uplink symbols, converting flexible symbols to uplink, and considering PUCCH format, size, and timing to ensure reliable transmission of delayed HARQ-ACK codebooks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE determines PUCCH resources based on the latest received DCI without considering delayed HARQ-ack codebook, then the PUCCH resource determination is simple and fast, but the HARQ-ack feedback may be missed or incorrectly transmitted due to resource collision
Solution Approach 1:
The UE performs preliminary determination of the delayed HARQ-ack codebook based on previously received DCIs before the current PUCCH transmission. This preliminary action allows the UE to identify overlapping PUCCH resources in advance and adjust the codebook determination accordingly, preventing HARQ-ack feedback loss while maintaining efficient resource allocation.
2Device complexity
If the UE uses type-1 codebook determination method, then the codebook size is smaller and processing is simpler, but the method cannot handle delayed HARQ-ack scenarios properly
Solution Approach 1:
The UE dynamically determines the codebook type based on the actual transmission scenario. When delayed HARQ-ack is detected through DCI examination, the UE switches from static type-1 codebook determination to dynamic type-2 codebook determination. This dynamic adaptation allows the system to maintain simplicity for normal operations while ensuring reliability for delayed HARQ-ack scenarios.
3Ease of manufacture
If the network configures PUCCH resources without considering delayed HARQ-ack codebook, then the resource configuration is simpler and faster, but resource collisions occur leading to feedback loss
Solution Approach 1:
The UE examines the DCI to determine whether delayed HARQ-ack codebook transmission is configured, and provides feedback information to the network about the overlapping PUCCH resources. This feedback mechanism enables the network to adjust resource allocation dynamically, preventing resource collisions while maintaining configuration simplicity through automated UE-initiated adjustments.
Data Source
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AI summary
Systems, methods and devices for determining PUCCH of delayed HARQ-ACK codebook may include A wireless communication device determining, in response to an event, to delay sending of uplink control information (UCI), by sending the UCI in a valid physical uplink control channel (PUCCH) occasion determined according to at least one configuration, instead of sending the UCI in an indicated PUCCH occasion that is invalid and prior to the valid PUCCH. The wireless communication device determine may the valid PUCCH occasion from a plurality of candidate PUCCH occasions, according to the at least one configuration.