HARQ-ACK Multiplexing on PUSCH for Overlap Decoding Consistency
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Solution Overview
Problem
In wireless communication systems, particularly in NR-U systems, there is a challenge in handling HARQ-ACK feedback transmission when a configured grant physical uplink shared channel (PUSCH) overlaps with a physical uplink control channel (PUCCH) on an unlicensed spectrum, leading to inconsistencies in decoding due to mismatched HARQ-ACK codebook sizes between the user equipment (UE) and the base station (BS).
Innovation Solution
The method involves separately encoding configured grant uplink control information (CG-UCI) and HARQ-ACK feedback, and then transmitting them on the PUSCH, using techniques such as Reed-Muller or polar coding, with additional mechanisms to align the HARQ-ACK codebook sizes by indicating the downlink assignment index (DAI) or using predefined sets to ensure consistent decoding at both the UE and BS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK feedback is transmitted on PUCCH separately from CG-UCI, then the control information can be transmitted with dedicated resources, but when PUCCH overlaps with PUSCH, resource conflicts occur and decoding consistency cannot be ensured
Solution Approach 1:
The patent merges HARQ-ACK feedback transmission with CG-UCI transmission by multiplexing both on the PUSCH. Instead of maintaining separate PUCCH and PUSCH transmissions, the solution combines these control information types into a single PUSCH transmission, eliminating resource conflicts and ensuring decoding consistency between UE and BS.
Solution Approach 2:
The PUSCH is made multi-functional by enabling it to carry both CG-UCI and HARQ-ACK feedback simultaneously. This universal approach allows a single channel to serve multiple purposes, resolving the contradiction between dedicated resource transmission and flexible resource utilization.
2Reliability
If HARQ-ACK feedback and CG-UCI are multiplexed on PUSCH, then resource conflicts are resolved and decoding consistency is improved, but the complexity of encoding and multiplexing increases
Solution Approach 1:
The patent segments the encoding process into separate steps: first encoding CG-UCI, then encoding HARQ-ACK feedback, and finally multiplexing them together on the PUSCH. This segmentation allows for manageable encoding complexity while ensuring proper codebook size alignment and reliable decoding.
3Measurement precision
If separate encoding of CG-UCI and HARQ-ACK feedback is used, then decoding accuracy is improved, but transmission time increases
Solution Approach 1:
By merging the encoding of CG-UCI and HARQ-ACK feedback into a unified process that occurs within the same transmission time window, the patent achieves both high decoding accuracy through separate encoding and efficient transmission time utilization. The multiplexed PUSCH transmission delivers both encoded information simultaneously without requiring separate transmission slots.
Data Source
AI summary
Embodiments of the present disclosure relate to methods and apparatuses. According to some embodiments of the disclosure, a method for wireless communications performed by a UE may include: receiving, from a base station (BS), at least one downlink (DL) transmission with corresponding hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback to be transmitted in a physical uplink control channel (PUCCH) in a slot; determining that the PUCCH overlaps with a physical uplink shared channel (PUSCH), wherein the PUSCH is configured to be transmitted by the UE in the slot; and transmitting, to the BS, the PUSCH in the slot, wherein configured grant uplink control information (CG-UCI) associated with the PUSCH and the HARQ-ACK feedback are multiplexed on the PUSCH.