LBT-Aware Autonomous Sidelink Sensing for 5G NR
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in sidelink communications over shared radio frequency bands due to channel access uncertainty and outdated resource selection windows, leading to inefficiencies in LBT-aware autonomous sensing.
Innovation Solution
A method where a UE determines a sensing window and resource selection window based on projected LBT completion time, filtering resources to accommodate LBT procedures, ensuring reliable resource selection and improved performance by excluding resources with significant LBT gaps or overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If autonomous sensing is performed without considering LBT completion time, then resource selection process is simpler, but resource selection becomes outdated and unreliable due to channel access uncertainty
Solution Approach 1:
The UE performs sensing actions in advance based on projected LBT completion time. The sensing window and resource selection window are determined before the actual LBT procedure completes, allowing the UE to prepare resource selections proactively rather than reactively, thus improving reliability while managing complexity through advance planning
Solution Approach 2:
The sensing window and resource selection window are made dynamic by adjusting their timing and duration based on the projected LBT completion time. This dynamic adaptation allows the system to flexibly respond to varying LBT durations and channel conditions, resolving the contradiction between reliability and complexity
2Reliability
If resource selection window is determined without LBT completion time consideration, then resource selection is faster, but selected resources may have significant LBT gaps or overlaps reducing performance
Solution Approach 1:
The UE determines the resource selection window timing in advance based on projected LBT completion time, identifying suitable resources before the LBT procedure actually completes. This preliminary determination ensures resources are selected with proper timing margins, avoiding LBT gaps and overlaps while minimizing delays through advance planning
Solution Approach 2:
The UE skips unnecessary waiting time by projecting LBT completion time and determining resource selection window accordingly. Instead of waiting for LBT to complete before selecting resources, the system rushes through the process by making informed selections in advance, reducing delays while maintaining reliability
3Measurement precision
If sensing window is extended to capture more recent sensing results, then resource selection accuracy improves, but processing time and complexity increase
Solution Approach 1:
The sensing window duration and timing are made dynamic, adjusted based on the projected LBT completion time and specific channel conditions. This allows the system to extend the sensing window when needed to capture sufficient sensing results, while dynamically adjusting the window size to avoid excessive processing time, resolving the contradiction between accuracy and time
Data Source
AI summary
Wireless communications systems and methods related to LBT aware autonomous sidelink sensing are provided. A first UE determines, based on a projected listen-before-talk (LBT) completion time, at least one of a sensing window or a first resource selection window. The first UE senses, based on the determining, in a sidelink resource pool within a shared radio frequency band during the sensing window. The first UE identifies, based on the sensing, a subset of resources from the sidelink resource pool that are within the first resource selection window. The first UE selects at least a first resource from the subset of resources. The first UE transmits, to a second UE using the selected first resource, a sidelink transmission.