Adaptive Cyclic-Shift Selection for Sidelink HARQ-ACK and CSI
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently multiplexing Hybrid Automatic Repeat Request (HARQ) acknowledgement and Channel State Information (CSI) feedback for sidelink communications, particularly in NR sidelink communications, due to limitations in cyclic shift pair configurations for physical sidelink feedback channels (PSFCH), which can lead to detection errors and inefficiencies in resource utilization.
Innovation Solution
A method and apparatus for selecting cyclic shift values for HARQ-ACK and CSI feedback based on bit values associated with HARQ-ACK and CSI feedback, allowing for equal or unequal distances between cyclic shift values, and potentially using multiple PSFCH resources to transmit CSI feedback, including repurposing NACK bits for additional CSI feedback, to improve multiplexing efficiency and reduce detection errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cyclic shift pair configurations for PSFCH are limited, then device complexity is reduced, but multiplexing efficiency and reliability of HARQ-ACK and CSI feedback deteriorate
Solution Approach 1:
The patent applies dynamics by making the cyclic shift configuration adaptive rather than fixed. The system dynamically selects cyclic shift values based on the actual feedback bits to be transmitted (HARQ-ACK and CSI), allowing the configuration to change according to transmission requirements. This resolves the contradiction by enabling efficient multiplexing only when needed while maintaining simplicity for basic cases.
Solution Approach 2:
The patent changes the parameter of cyclic shift values based on the feedback bit values. Different cyclic shift values are selected depending on the combination of HARQ-ACK and CSI feedback bits, creating a mapping between feedback states and cyclic shift configurations. This allows the system to optimize multiplexing efficiency for each feedback scenario without requiring all possible configurations to be always active.
2Productivity
If multiple PSFCH resources are used for CSI feedback, then multiplexing efficiency is improved, but device complexity and resource utilization efficiency deteriorate
Solution Approach 1:
The patent applies universality by enabling PSFCH resources to serve multiple functions. The same PSFCH resource can carry different combinations of HARQ-ACK and CSI feedback depending on the cyclic shift configuration used. This allows a single resource to be universally used for various feedback types, improving multiplexing efficiency without proportionally increasing device complexity.
Solution Approach 2:
The system dynamically determines which PSFCH resource to use based on the feedback content and configured cyclic shift values. Rather than statically allocating separate resources for different feedback types, the system adapts its resource selection in real-time, optimizing resource utilization efficiency while managing complexity through dynamic rather than static resource management.
3Productivity
If NACK bits are repurposed for CSI feedback, then resource utilization efficiency is improved, but reliability of HARQ-ACK feedback may deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the feedback transmission into distinct phases or stages. The HARQ-ACK feedback is transmitted first using one set of cyclic shift values, and then CSI feedback is transmitted using different cyclic shift values. This temporal or sequential segmentation allows NACK bits to be repurposed for CSI without interfering with the initial HARQ-ACK transmission, maintaining reliability while improving resource utilization.
Solution Approach 2:
The system uses feedback mechanisms to ensure reliable transmission. By transmitting HARQ-ACK feedback first and then CSI feedback with different cyclic shift configurations, the system creates a feedback loop where the receiver can accurately distinguish between the two types of feedback based on the cyclic shift values used. This feedback approach allows NACK bit repurposing while maintaining HARQ-ACK reliability through proper sequencing and differentiation.
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may receive, from a second UE, a sidelink communication via a physical sidelink shared channel (PSSCH). The UE may transmit, to the second UE and based at least in part on the sidelink communication via the PSSCH, hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback and channel state information (CSI) feedback on a single physical sidelink feedback channel (PSFCH) resource. Numerous other aspects are described.