Sidelink CAPC Selection Under PDB Constraints in Shared Spectrum
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Solution Overview
Problem
Existing wireless communication systems face mismatches between Channel Access Priority Class (CAPC) selection and Packet Delay Budget (PDB) requirements in sidelink operations, leading to potential LBT procedure failures and incorrect channel access parameters for sidelink transmissions.
Innovation Solution
A UE selects the highest priority CAPC for sidelink transmissions when the highest priority CAPC is above a preconfigured threshold, or the lowest priority CAPC when below, ensuring alignment with PDB requirements to optimize channel access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lowest priority CAPC is selected for SL TB, then channel access parameters are more conservative, but transmission timeliness deteriorates and may fail to meet PDB requirements
Solution Approach 1:
The patent applies dynamics by making the CAPC selection adaptive rather than static. The UE dynamically selects the CAPC based on the highest priority LCH present in the SL TB, allowing the system to adjust channel access parameters in real-time according to the actual data priority, thus resolving the contradiction between conservative reliability and timely transmission.
Solution Approach 2:
The patent changes the parameter selection criterion from lowest priority to highest priority CAPC based on the specific transmission requirements. By selecting the CAPC corresponding to the highest priority LCH, the system adjusts channel access parameters (such as contention window size, defer period) to match the actual urgency of the data, ensuring both reliability and timeliness.
2Loss of time
If the highest priority CAPC is selected for SL TB, then transmission timeliness is improved, but channel access parameters become overly aggressive, potentially causing interference
Solution Approach 1:
The patent applies local quality by applying different CAPC priorities to different LCHs within the same SL TB. Instead of using a single fixed priority for all data, the system identifies the highest priority LCH and applies its corresponding CAPC, ensuring that only the most time-sensitive data drives the channel access behavior, thus avoiding overly aggressive access while meeting critical delay requirements.
3Ease of operation
If CAPC selection does not consider PDB requirements, then channel access is simplified, but transmission failures increase due to mismatched parameters
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously determine the appropriate CAPC based on the priority information of LCHs present in the SL TB. The system automatically matches the highest priority LCH with its corresponding CAPC without requiring external configuration or complex algorithms, thus maintaining operational simplicity while significantly improving transmission reliability through proper parameter matching.
Data Source
AI summary
Various aspects of the present disclosure relate to sidelink (SL) operation in a cell with shared spectrum channel access. A UE may be configured to generate an SL transport block (TB) to be transmitted to a set of Rx UEs, the TB including data units from multiple SL logical channels (LCHs), each SL LCH associated with a respective channel access priority class (CAPC). The UE may be configured to determine a highest priority CAPC associated with the SL TB and to select a CAPC value for the SL TB based at least in part on the highest priority CAPC satisfying a threshold. The UE may be configured to perform a listen-before-talk (LBT) procedure using parameters corresponding to the selected CAPC value and to transmit the SL TB based at least in part on a success of the LBT procedure.