NR V2X Sidelink Resource Selection for HARQ Collision Avoidance
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Solution Overview
Problem
In sidelink communication, when hybrid automatic repeat request (HARQ) feedback is enabled, random selection of resources can lead to collisions, particularly in scenarios where UEs receive ACK/NACK based on physical sidelink feedback channels (PSFCH) resources, complicating retransmission judgments.
Innovation Solution
Disallowing random selection for resource allocation when HARQ feedback is enabled, allowing UEs to select resources within a sensing window based on sensing results to avoid collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If random selection is performed for resource allocation, then resource allocation flexibility is improved, but resource collision occurs making retransmission judgment difficult
Solution Approach 1:
The patent changes the resource selection parameter from random selection to sensing-based selection. The UE performs sensing operations to detect channel conditions and selects resources based on sensed information, transforming the selection mechanism from stochastic to deterministic based on channel state, thereby avoiding collisions while maintaining allocation flexibility
Solution Approach 2:
The patent introduces feedback mechanisms where UEs perform sensing operations and use the sensed information to make resource selection decisions. This feedback loop allows UEs to adapt their resource selection based on channel conditions and other UE transmissions, preventing collisions and enabling accurate retransmission judgment through proper resource coordination
2Reliability
If partial sensing is performed for resource selection, then resource collision is avoided, but sensing complexity increases
Solution Approach 1:
The patent implements partial sensing where UEs perform sensing operations for a subset of resources or during specific time periods rather than continuous full sensing. This partial action approach provides sufficient collision avoidance information while limiting the complexity and power consumption associated with comprehensive sensing
Solution Approach 2:
The sensing process is segmented into discrete operations performed at specific intervals or for specific resource subsets. Rather than continuous sensing, the UE performs sensing in segments, processing information in manageable portions that reduce computational complexity while maintaining effective collision avoidance
Data Source
AI summary
An embodiment proposes a method for performing wireless communication by a first device. The method may comprise the steps of: selecting a first resource within a first selection window on the basis of first sensing; generating a first medium access control (MAC) protocol data unit (PDU) on the basis of at least one logical channel (LCH) in which hybrid automatic repeat request (HARQ) feedback is enabled; transmitting, to a second device, first sidelink control information (SCI) for scheduling a first physical sidelink shared channel (PSSCH), through a first physical sidelink control channel (PSCCH), on the basis of the first resource; and transmitting, to the second device, second SCI and the first MAC PDU, through the first PSSCH, on the basis of the first resource. For example, random selection of the first resource may not be allowed on the basis of the at least one LCH in which the HARQ feedback is enabled.