PSFCH Resource Determination for NR V2X Feedback
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Solution Overview
Problem
In NR V2X scenarios, User Equipment (UE) is unable to acquire resources for the Physical Sidelink Feedback Channel (PSFCH) from resource pools configured by the network or pre-configured, due to the lack of a feedback mechanism in LTE V2X.
Innovation Solution
A feedback resource determination method that involves acquiring a first resource set for the Physical Sidelink Shared Channel (PSSCH), determining candidate time domain positions for the PSFCH based on the time difference between PSSCH and PSFCH, and excluding positions with unavailable symbols to accurately determine the resources for PSFCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTE V2X resource pools are configured for PSSCH and PSCCH without feedback mechanism, then resource allocation is simple, but UE cannot acquire PSFCH resources and reliability of unicast/multicast communication cannot be improved
Solution Approach 1:
The patent applies preliminary action by pre-configuring time difference values between PSSCH and PSFCH resources. The network pre-determines and signals the time offset (e.g., slot offset) that receivers will use to calculate feedback resource positions. This allows UEs to proactively determine PSFCH resources without real-time computation, resolving the contradiction by enabling reliability improvement through feedback while maintaining simple resource allocation procedures.
Solution Approach 2:
The patent implements self-service by enabling UEs to autonomously calculate and determine their own PSFCH resources based on pre-configured parameters and their transmitted/received PSSCH resource positions. Each UE independently derives feedback resource locations using the formula: PSFCH resource position = f(PSSCH resource position + time difference). This self-determination mechanism improves communication reliability through feedback while avoiding complex network-controlled resource allocation.
2Productivity
If PSFCH resources are determined without considering unavailable symbols, then resource determination is simple, but resource allocation conflicts occur and resource utilization decreases
Solution Approach 1:
The patent applies preliminary action by pre-identifying and marking unavailable symbols (e.g., downlink symbols, flexible symbols configured for other purposes) before PSFCH resource allocation. The network signals which symbols are unavailable, and UEs use this information in advance to select alternative valid resources. This prevents allocation conflicts and improves resource utilization while keeping the determination process straightforward through pre-established availability rules.
Solution Approach 2:
The patent implements inversion by reversing the traditional approach: instead of allocating resources and then checking for conflicts, the system first identifies unavailable resources and then allocates PSFCH resources exclusively from the remaining valid set. This inverted allocation strategy ensures resource validity by construction, improving productivity while maintaining simple determination logic through exclusion-based selection.
3Adaptability or versatility
If extra signaling configuration is added to enable PSFCH resource acquisition, then UE can acquire feedback resources, but signaling overhead increases
Solution Approach 1:
The patent applies universality by designing the time difference parameter to serve multiple functions simultaneously: it defines the feedback timing relationship, determines resource offset calculations, and works across different unicast and multicast scenarios. This single multi-functional parameter enables PSFCH resource acquisition without requiring separate signaling for each scenario, achieving adaptability while minimizing signaling overhead through parameter reuse.
Solution Approach 2:
The patent implements parameter changes by utilizing existing time difference parameters (already used for timing alignment and scheduling purposes) and repurposing them for PSFCH resource determination. By changing the interpretation and application of existing parameters rather than introducing new ones, the system achieves the capability to acquire feedback resources while avoiding additional signaling overhead.
Data Source
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AI summary
Provided are a feedback resource determination method and apparatus for a V2X service, and a storage medium and a terminal. The method comprises: acquiring a first resource set, wherein the first resource set comprises a time domain position of at least one first resource; for each first resource, determining, according to the time domain position of the first resource and associated feedback information, a candidate time domain position of a second resource corresponding to the first resource, wherein the associated feedback information is used for indicating a time difference between a PSSCH and a PSFCH; for each candidate time domain position, determining whether symbols occupied by the candidate time domain position include an unavailable symbol, wherein the unavailable symbol refers to a symbol that cannot be used for transmitting a second resource; and when a determination result indicates that the symbols occupied by the candidate time domain position do not include an unavailable symbol, determining that the candidate time domain position is a time domain position of the second resource. According to the solution provided in the present invention, a UE in an NRV2X scenario can efficiently and accurately determine resources of a sidelink feedback channel.