Sidelink Collision Avoidance via PSFCH Sensing
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Solution Overview
Problem
In 5G NR sidelink communication systems, there is a challenge in avoiding collisions between data transmissions due to hidden nodes, where a transmitter UE may not be able to sense transmissions from a hidden UE, leading to potential interference with intended recipients.
Innovation Solution
The proposed solution involves a UE that senses sidelink feedback transmissions from a receiver UE in Physical Sidelink Feedback Channel (PSFCH) resources to determine the radio resources used by the receiver UE for data transmissions. Based on this information, the UE can deprioritize or exclude candidate radio resources that overlap with the determined resources to avoid collisions, and trigger radio resource reselection if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transmitter UE performs sensing to detect ongoing transmissions before selecting radio resources, then collision avoidance is improved, but hidden nodes cannot be detected leading to residual interference
Solution Approach 1:
The transmitter UE performs sensing operations in advance before selecting radio resources for data transmission. By sensing PSFCH resources and determining associated radio resources beforehand, the UE can identify and exclude resources that would cause collisions with ongoing transmissions, thereby improving collision avoidance reliability
Solution Approach 2:
The patent uses PSFCH (Physical Sidelink Feedback Channel) resources as an intermediary indicator to infer the presence of hidden transmissions. Since PSFCH resources are directly associated with radio resources used by receiver UEs, sensing PSFCH provides indirect information about ongoing data transmissions that would be invisible through direct sensing alone, thus addressing the hidden node problem
2Reliability
If a transmitter UE excludes candidate radio resources that overlap with determined radio resources, then collision avoidance is enhanced, but the pool of available resources for transmission is reduced
Solution Approach 1:
The transmitter UE performs resource exclusion in advance during the resource selection phase, before actual data transmission occurs. By determining radio resources associated with sensed PSFCH and excluding overlapping candidate resources beforehand, the UE ensures collision-free transmission while maximizing the use of remaining available resources
Solution Approach 2:
The sensing and resource determination mechanism serves the transmitter UE itself by providing it with information about hidden transmissions. The UE uses this self-acquired information to autonomously make informed resource selection decisions, excluding only those resources that would cause interference while keeping other resources available for its own transmissions
Data Source
AI summary
Systems, methods, and apparatuses for sidelink collision avoidance based on sensing, such as PSFCH sensing, are provided. One method may include sensing, by a first UE, a first sidelink feedback transmission from a second UE in a first PSFCH resource, and determining, based on the first PSFCH resource, a first radio resource in which the second UE received a first data transmission from a third UE. The method may also include sensing a second sidelink feedback transmission from the second UE in a second PSFCH resource, determining, based on the second PSFCH resource, a second radio resource in which the second UE received a second data transmission from the third UE, and determining, based on at least one of the determined first radio resource or second radio resource, a third radio resource in which the second UE is expected to receive a third data transmission from the third UE.