Sidelink Feedback Resource Configuration for Unlicensed Spectrum
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Solution Overview
Problem
Current solutions for sidelink communication in licensed spectrum lack flexibility and efficiency, particularly in unlicensed spectrum where listen-before-talk (LBT) is required, leading to unreliable feedback information transmission and unnecessary re-transmissions due to uncertain channel assessment results.
Innovation Solution
Configuring primary and backup resources for feedback information transmission without performing channel assessment, allowing for timely and reliable feedback even in unlicensed spectrum by prioritizing primary resources and using backup resources when primary ones are unavailable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If channel assessment (LBT) is performed before feedback transmission on unlicensed resources, then collision avoidance with other systems is improved, but transmission reliability deteriorates due to uncertain channel availability
Solution Approach 1:
The patent configures backup resources in advance for feedback transmission without requiring channel assessment. When primary resources are unavailable due to LBT failure, the receiving device can immediately use the pre-configured backup resources to transmit feedback, eliminating the need for real-time channel assessment and ensuring reliable feedback delivery.
Solution Approach 2:
The patent introduces backup resources as a cushioning mechanism against LBT failures. These backup resources are prepared beforehand and can be activated when primary transmission fails, providing a safety net that ensures feedback transmission reliability even when channel conditions are unfavorable.
2Reliability
If channel assessment is performed before feedback transmission, then channel access reliability is improved, but transmission latency increases due to assessment time
Solution Approach 1:
The patent performs the channel access preparation in advance by configuring both primary and backup resources through higher-layer signaling. This preliminary configuration eliminates the need for real-time channel assessment before feedback transmission, allowing the receiving device to immediately transmit feedback on available resources and significantly reducing transmission latency.
3Reliability
If multiple resources are configured for feedback transmission, then transmission reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments feedback transmission resources into primary resources (requiring LBT) and backup resources (no LBT required). This segmentation allows the device to use simple, clear rules for resource selection: attempt primary resources first, and if unsuccessful, immediately use backup resources. The segmented approach simplifies the decision-making process while ensuring reliable feedback transmission.
4Speed
If backup resources are used without channel assessment, then transmission speed is improved, but spectral efficiency may deteriorate due to potential collisions
Solution Approach 1:
The patent applies partial channel assessment by requiring LBT only for primary resources while allowing backup resources to be used without full channel assessment. This partial approach balances speed and spectral efficiency: backup resources provide fast feedback transmission when primary resources are unavailable, while the limited scope of LBT-free transmission minimizes potential collisions and maintains acceptable spectral efficiency.
Data Source
AI summary
Embodiments of the present disclosure relate to transmission of sidelink feedback information on unlicensed spectrum. The first device transmits a configuration to a second device and a third device. The configuration indicates a primary resource and at least one backup resource, where the primary resource is to be used by the third device for transmitting feedback information of a sidelink transmission to the second device, the sidelink transmission being transmitted by the second device on an unlicensed resource, and the at least one backup resource is to be used by the third device for transmitting the feedback information of the sidelink transmission without performing a channel assessment.