Logical Channel Prioritization for Delay-Critical Uplink Data
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Solution Overview
Problem
The priority-based token bucket algorithm in LCP procedures for 5G NR does not adequately address the transmission requirements of delay-critical data, leading to potential delays in critical data transmission despite higher priority, which is detrimental to low-latency applications like XR and telesurgery.
Innovation Solution
Enhance the LCP procedure by allocating resources to logical channels with delay-critical data even if they have a non-positive number of tokens, and optionally exempting or reducing the decrement of tokens for such channels to ensure they always have a positive number, thereby prioritizing their resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the priority-based token bucket algorithm is used for UL resource allocation, then PBR-based fairness is achieved, but delay-critical data transmission is not ensured
Solution Approach 1:
The patent segments the logical channels into two categories: those with delay-critical data and those without. This segmentation allows different resource allocation strategies to be applied to each category, ensuring that delay-critical data receives prioritized treatment while maintaining PBR-based fairness for other data types.
Solution Approach 2:
The patent introduces dynamic behavior by allowing logical channels with delay-critical data to preemptively claim resources before the token bucket algorithm processes them. The algorithm dynamically adjusts the allocation process based on whether data is marked as delay-critical, enabling real-time response to urgent transmission needs while maintaining overall fairness.
2Productivity
If strict decreasing priority order allocation is applied to all logical channels, then high priority channels are served first, but delay-critical data in lower priority channels cannot be transmitted timely
Solution Approach 1:
The patent applies preliminary action by allowing logical channels with delay-critical data to perform a preliminary resource claim before the standard token bucket allocation process. This preliminary action ensures that urgent data is secured first, and only then does the algorithm proceed with the常规 PBR-based allocation for other channels.
Solution Approach 2:
The patent applies local quality by treating logical channels with delay-critical data differently from those without. Instead of uniform treatment, the system applies enhanced prioritization rules specifically to channels carrying delay-critical data, allowing them to bypass certain allocation constraints while maintaining standard rules for other channels.
3Measurement precision
If tokens are decremented for all logical channels, then accurate token tracking is maintained, but delay-critical data may be blocked from allocation when tokens are non-positive
Solution Approach 1:
The patent extracts the token decrement operation from the universal allocation process and applies it selectively. Tokens are decremented only for logical channels without delay-critical data, while channels with delay-critical data are exempted from this operation. This extraction allows accurate token tracking for non-critical channels while preventing token-based blocking of critical data transmission.
Solution Approach 2:
The patent applies preliminary action by allowing delay-critical data to perform a preliminary resource claim before the token decrement operation is applied. This ensures that critical data can secure allocation resources even when tokens would otherwise be non-positive, while still maintaining accurate token tracking for other channels.
Data Source
AI summary
Various solutions for logical channel prioritization (LCP) enhancements in mobile communications are described. An apparatus may select a plurality of logical channels for an uplink (UL) grant. The apparatus may allocate resources of the UL grant to one or more of the plurality of logical channels in a decreasing priority order. Each of the one or more of the plurality of logical channels carries delay-critical data or is associated with a positive number of tokens. Then, the apparatus may decrement the positive number of tokens for each of the one or more of the plurality of logical channels by a total size of medium access control (MAC) service data units (SDUs) served to a corresponding logical channel of the one or more of the plurality of logical channels. After that, the apparatus may multiplex the MAC SDUs in a MAC protocol data unit (PDU) for transmission on the UL grant to a network node.