Transport Block Size Scaling for Wireless TTI Adaptation

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Solution Overview

Problem

Conventional techniques struggle to adapt transport block size (TBS) effectively to varying transmission time interval (TTI) lengths and different services, leading to suboptimal code rates that affect transmission robustness.

Innovation Solution

A method where a scaling factor is dynamically or semi-statically configured by the network for different services, TTI lengths, directions, transmission modes, and downlink control information (DCI) types, allowing the user equipment (UE) to compute the TBS based on the modulation and coding scheme (MCS) and a default TBS table.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed TBS calculation method is used, then the calculation is simple, but the code rate cannot be adapted to varying TTI lengths and services

Engineering Contradiction:
Improvecode rate adaptationVSAvoidTBS calculation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a scaling factor parameter that modifies the base TBS calculation to adapt to different TTI lengths and service types. The scaling factor is determined based on the ratio of actual TTI length to reference TTI length, allowing the code rate to be dynamically adjusted without fundamentally changing the TBS calculation methodology.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent pre-configures scaling factors for different service types and TTI length combinations. This allows the UE to quickly determine the appropriate scaling factor by simple lookup rather than performing complex real-time calculations, reducing computational complexity while maintaining adaptability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the TBS is not adapted to TTI length, then the calculation is straightforward, but the code rate becomes higher than intended

Engineering Contradiction:
Improvetransmission robustnessVSAvoiddata transmission efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The scaling factor directly adjusts the TBS based on TTI length, ensuring that shorter TTIs result in proportionally smaller TBS values. This maintains the intended code rate and transmission robustness for different service types while preventing excessive code rates that would reduce data transmission efficiency.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If different code rates are configured for different services, then transmission robustness improves, but the configuration complexity increases

Engineering Contradiction:
Improveservice-specific transmission robustnessVSAvoidconfiguration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies different scaling factors for different service types (e.g., eMBB, URLLC, mMTC) to achieve service-specific code rates and transmission robustness. Each service type has its own scaling factor configuration that is optimized for its requirements, allowing local optimization without affecting other services.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The network pre-configures service-specific scaling factors and parameters before data transmission begins. This allows the UE to simply apply the pre-configured parameters for each service type without performing complex real-time adjustments, reducing configuration complexity while maintaining service-specific optimization.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3688901B1Transport block size configuration
Publication Date: 2025.01.29 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3688901B1 patent drawingFigure 1
  • EP3688901B1 patent drawingFigure 2A~2B
  • EP3688901B1 patent drawingFigure 3A~3B

AI summary

A wireless communication device determines a base value for a transport block size, determines a scaling factor for the transport block size, applies the scaling factor to the base value to determine the transport block size, and receives information from a radio access node according to the determined transport block size.