Sidelink Resource Reselection for Unlicensed Band LBT Failures
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently communicating on unlicensed frequency bands due to interference from other communication systems and the need to limit interference to other systems, which is not effectively addressed by current methods.
Innovation Solution
A method and apparatus for user equipment (UE) in a wireless communication system that determines resources for sidelink (SL) transmission, identifies unavailable resources due to listen before talk (LBT) failures or overlap with other UE resources, and performs resource reselection to ensure successful transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If listen before talk (LBT) is performed before transmission, then interference to other communication systems is limited, but transmission reliability deteriorates due to LBT failures
Solution Approach 1:
The patent applies preliminary action by performing LBT before each transmission to ensure the channel is clear, preventing interference to other systems. This preliminary check is performed before both initial transmission and retransmission, establishing a reliable mechanism to avoid harmful interference while preparing for successful transmission.
Solution Approach 2:
The patent implements feedback by having the UE determine whether LBT was successful before initiating transmission. The UE receives feedback information indicating LBT success or failure, and based on this feedback, the UE decides whether to perform retransmission, thereby adjusting transmission behavior according to LBT outcomes to maintain reliability.
2Device complexity
If resource selection is performed without considering LBT failure probability, then resource allocation is simple, but transmission success rate deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the resource selection process to incorporate LBT failure probability as a key parameter. The UE determines LBT failure probability based on channel conditions and uses this parameter to adjust resource selection, choosing resources that are less likely to result in LBT failure, thereby improving transmission success rate while managing complexity through parameter-based decision making.
3Reliability
If retransmission is performed without resource reselection, then transmission reliability improves, but interference to other systems increases due to repeated LBT failures
Solution Approach 1:
The patent applies dynamics by making the resource selection process adaptive and dynamic. Instead of using fixed resource allocation, the UE dynamically selects resources based on real-time LBT outcomes and channel conditions. When LBT fails, the UE reselects different resources for retransmission, dynamically adjusting the transmission strategy to avoid repeated interference while maintaining reliability.
Solution Approach 2:
The patent applies preliminary action by performing LBT before each retransmission to ensure the channel is clear before attempting to send data again. This preliminary LBT check before retransmission prevents unnecessary interference to other systems while still allowing retransmission when LBT succeeds, thereby maintaining reliability without causing harmful interference.
4Productivity
If multiple consecutive slots are used for transmission, then data transmission efficiency improves, but vulnerability to LBT failure increases
Solution Approach 1:
The patent applies preliminary action by performing LBT before initiating a sequence of transmissions in multiple consecutive slots. This preliminary LBT ensures the channel is clear before starting the efficient multi-slot transmission sequence, allowing high productivity to be achieved while maintaining reliability through proper channel clearance beforehand.
Solution Approach 2:
The patent implements feedback by monitoring LBT outcomes during multi-slot transmission sequences. When LBT failure is detected, the UE receives feedback information and adjusts the transmission strategy, potentially reducing the number of consecutive slots or changing resource selection, thereby maintaining transmission stability while preserving efficiency when conditions are favorable.
Data Source
AI summary
The disclosure relates to a fifth generation (5G) or sixth generation (6G) communication system for supporting a higher data transmission rate. A method and an apparatus in a wireless communication system include determining first resources for a sidelink (SL) transmission, the first resources including multiple consecutive time units, determining whether the first resources include second resources unavailable for the SL transmission, and performing reselection of at least one of the second resources and at least one of third resources in a case that the first resources include the second resources, wherein the third resources include resources other than the second resources among the first resources.