URLLC TBS Table Segmentation for Latency and Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Transport Block Size (TBS) tables in 3GPP standards are inadequate for achieving both high reliability and low latency in Ultra-Reliable and Low-Latency Communications (URLLC), as they often require trading off between these two conflicting aspects, and existing link adaptation mechanisms are not efficient for stringent latency requirements.
Innovation Solution
Introducing separate sets of TBS/MCS mapping tables for URLLC and non-URLLC traffic, with URLLC tables featuring finer granularity and lower minimum TBSs, and using scaling factors to generate these tables from existing ones, allowing for dynamic selection and configuration in network nodes and user equipment to meet varying reliability and latency demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard TBS tables are used for URLLC communication, then backward compatibility is maintained, but reliability and latency requirements cannot be simultaneously met
Solution Approach 1:
The patent segments the TBS table into multiple versions: a first TBS table for non-URLLC traffic and a second TBS table for URLLC traffic. This segmentation allows each table to be optimized for its specific traffic type, with the second table providing finer granularity and lower minimum TBS values to meet URLLC requirements while the first table maintains standard operation for other traffic.
Solution Approach 2:
The patent introduces dynamic selection between different TBS table versions based on traffic type. The network node determines whether incoming traffic is URLLC or non-URLLC and selects the appropriate TBS table accordingly. This dynamic adaptation enables the system to switch between standard and optimized TBS mappings in real-time, meeting both URLLC and non-URLLC requirements.
2Reliability
If time domain repetition is used for reliability boosting, then reliability improves, but latency increases which violates URLLC requirements
Solution Approach 1:
The patent changes the TBS parameter values in the second TBS table to be smaller and more finely granulated compared to the first table. By reducing the minimum TBS and increasing granularity, the system can allocate smaller, more precise resource blocks for URLLC traffic, reducing the amount of data to be transmitted and thus reducing latency while maintaining reliability through optimized resource allocation.
3Productivity
If dynamic link adaptation is used, then communication efficiency improves, but convergence time increases which is not allowed for latency rigorous URLLC
Solution Approach 1:
The patent prepares multiple TBS table versions in advance, with the second table pre-optimized for URLLC characteristics. When URLLC traffic is detected, the system immediately switches to the pre-prepared second TBS table without needing to perform dynamic calculations or convergence procedures. This preliminary preparation eliminates convergence time while maintaining efficient resource allocation for URLLC traffic.
Data Source
Figure 1
Figure 2~3
AI summary
According to the present disclosure, different TBS tables especially different TBS table sets are used for URLLC traffic and non-URLLC traffic. ATBS table for URLLC is selected by a network node, upon determination of traffic type as URLLC, and informed to a UE. The informing can be a TBS table index or a scaling factor. After receiving the information of TBS table selection, the UE identifies the selected TBS table from its TBS table set for URLLC, or generates a new TBS table based on the scaling factor and a corresponding TBS table.