NR-U Logical Channel Multiplexing Priority Control
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Solution Overview
Problem
In 5G New Radio-Unlicensed (NR-U) systems, the multiplexing of high priority and low priority logical channels (LCHs) results in the lowest priority assignment for transport blocks, leading to increased latency for high priority data transmission due to lower priority assignment.
Innovation Solution
Implementing a Channel Access Priority Class (CAPC)-based restriction rule, either through a configured threshold CAPC value or a flag per CAPC, to prevent low priority LCHs from being multiplexed with high priority LCHs, ensuring faster transmission of high priority data by maintaining higher priority for high priority LCHs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low priority LCHs are multiplexed with high priority LCHs in configured grants, then resource utilization is improved, but transmission priority is degraded (lowest priority assignment)
Solution Approach 1:
The patent segments the logical channels into high priority and low priority categories based on CAPC values, and applies different multiplexing rules to each segment. High priority LCHs (with CAPC below threshold) can be multiplexed together, while low priority LCHs (with CAPC at or above threshold) are restricted from being multiplexed with high priority LCHs, thus preserving priority levels while allowing resource utilization.
Solution Approach 2:
The patent applies different multiplexing characteristics to different parts of the system based on their priority level. High priority LCHs follow one multiplexing rule (allowing mixing with other high priority channels), while low priority LCHs follow a different rule (restricting mixing with high priority channels). This local differentiation ensures that priority is preserved where needed while still allowing resource consolidation where appropriate.
2Ease of operation
If low priority LCHs are multiplexed with high priority LCHs, then channel access is simplified, but latency for high priority data increases
Solution Approach 1:
By segmenting LCHs into priority-based groups and applying distinct multiplexing rules to each group, the patent maintains simple channel access procedures while preventing latency issues. The threshold-based segmentation ensures that high priority LCHs remain in a separate multiplexing domain, allowing them to access the channel without being delayed by low priority data.
Solution Approach 2:
The CAPC threshold acts as an intermediary criterion that mediates between the desire for simplified channel access and the need to minimize latency. It provides a clear decision boundary that determines which LCHs can be multiplexed together, thereby maintaining access simplicity while protecting high priority data from latency caused by low priority multiplexing.
3Reliability
If CAPC-based restriction rule is implemented, then high priority data transmission is improved, but system complexity increases
Solution Approach 1:
The patent changes the parameter used for multiplexing decision from a simple availability check to a CAPC-based threshold comparison. By introducing this parameter change, the system can distinguish between high and low priority LCHs and apply appropriate multiplexing rules, thereby improving high priority data transmission while managing complexity through a clear, threshold-based decision framework.
Solution Approach 2:
The CAPC threshold is configured in advance through RRC signaling, establishing the multiplexing rules before data transmission occurs. This preliminary configuration allows the UE to automatically apply the correct multiplexing logic without complex real-time decisions, thereby improving high priority data transmission while minimizing operational complexity.
4Reliability
If threshold-based CAPC restriction is applied, then priority preservation is improved, but multiplexing flexibility is reduced
Solution Approach 1:
The patent segments the multiplexing space into distinct regions based on CAPC thresholds. High priority LCHs (below threshold) and low priority LCHs (at or above threshold) are separated into different multiplexing domains. This segmentation preserves priority levels while maintaining flexibility within each domain, as LCHs within the same priority segment can still be multiplexed together.
Solution Approach 2:
The patent applies different multiplexing characteristics to different priority segments. Within the high priority segment, LCHs can be multiplexed freely to maximize resource utilization. Within the low priority segment, similar flexibility is maintained. The restriction only applies at the boundary between segments, preserving priority while allowing flexibility where appropriate.
Data Source
AI summary
A method of multiplexing logical channels (LCHs) in configured grants (CG) to enable faster transmission of high priority data in 5G New Radio-Unlicensed (NR-U) is proposed. Two options of imposing a CAPC-based restriction rule on multiplexing a low priority LCH with a high priority LCH are provided. In a first option, a threshold CAPC value is configured via RRC signaling. Data belonging to LCH having a priority lower than the CAPC threshold is not allowed to be multiplexed with data belonging to LCH having a priority higher than the CAPC threshold. In a second option, each CAPC has a flag indicating if the CPAC can have reduced priority via RRC signaling. If the flag is set for the CAPC, then data belonging to LCH assigned with the CAPC cannot be multiplexed with data belonging to lower priority LCHs.