HARQ Feedback Reporting in NR V2X Sidelink BWP
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Solution Overview
Problem
In a MODE 1 TX UE scenario, there is an ambiguity regarding which information to report to the base station through a pre-configured PUCCH resource when no PSSCH and/or PSCCH is transmitted to an RX UE.
Innovation Solution
The MODE 1 TX UE determines the information to transmit to the base station by receiving information related to sidelink bandwidth parts (BWP) and uplink BWP from the base station, and then generates and transmits ACK related to the transmission of data with HARQ feedback disabled, based on the sidelink resource in the sidelink BWP, and reports this ACK to the base station through the uplink resource in the uplink BWP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If MODE 1 TX UE uses pre-configured PUCCH resource to report information, then the reporting mechanism is established, but ambiguity arises regarding which information to report when no PSSCH and/or PSCCH is transmitted
Solution Approach 1:
The patent introduces HARQ feedback as a key element to resolve the information ambiguity. When no PSSCH and/or PSCCH is transmitted, the UE still needs to provide feedback information to the base station. The patent establishes that the UE should report HARQ feedback information (indicating no transmission occurred) through the pre-configured PUCCH resource, thereby eliminating ambiguity about what information to report.
Solution Approach 2:
The patent applies preliminary action by having the UE prepare and transmit HARQ feedback information in advance through the pre-configured PUCCH resource. This ensures that the base station receives necessary information about transmission status before any potential retransmission or resource allocation decision is made, resolving the ambiguity proactively.
2Productivity
If the UE transmits data with HARQ feedback disabled on sidelink, then direct communication efficiency is improved, but the base station needs to receive ACK information through uplink resource
Solution Approach 1:
The patent segments the communication system into two distinct bandwidth parts: a sidelink BWP for direct UE-to-UE communication with HARQ feedback disabled (for efficiency), and an uplink BWP for reporting ACK information to the base station. This segmentation allows each part to serve its specific function optimally without interfering with the other, resolving the complexity by organizing functions spatially in the frequency domain.
Solution Approach 2:
The patent introduces the uplink resource as an intermediary mechanism. Instead of the sidelink directly reporting to the base station (which would require network coverage and increase complexity), the UE uses the uplink resource configured by the base station to report ACK information. This intermediary approach maintains the efficiency of direct sidelink communication while ensuring the base station is informed through a controlled pathway.
Data Source
AI summary
Provided is a method by which a first apparatus performs wireless communication and an apparatus for supporting the method. The method comprises the steps of: receiving, from a base station, information related to a sidelink (SL) bandwidth part (BWP); receiving, from the base station, information related to an uplink (UL) BWP; receiving, from the base station, information related to an SL resource and information related to a UL resource for reporting a hybrid automatic repeat request (HARQ) feedback; transmitting, on the basis of the SL resource within the SL BWP, data in which the HARQ feedback has been disabled to a second apparatus through a physical sidelink shared channel (PSSCH); generating an ACK related to the transmission of the data in which the HARQ feedback has been disabled; and transmitting, to the base station, the ACK on the basis of the UL resource within the UL BWP.