Random Access Preamble Repetition for Variable Channel Quality

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Solution Overview

Problem

The inefficiency of using a fixed repetition number for all preambles to which the MSG1 repetition feature is applied in wireless communication systems is a challenge, leading to suboptimal performance and increased signaling overhead.

Innovation Solution

A method for determining the repetition number of random access preambles based on channel quality, using a plurality of preamble configurations and RACH configurations, including BWP-uplink common configurations, to support multiple repetition numbers suitable for varying channel conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed repetition number is used for all preambles to which the MSG1 repetition feature is applied, then the configuration is simple, but the transmission efficiency is reduced and signaling overhead is increased

Engineering Contradiction:
Improveconfiguration complexityVSAvoidtransmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments the RACH configuration into multiple preamble configurations, where each configuration is associated with a specific repetition number. This segmentation allows the system to move away from a single fixed repetition number for all preambles, enabling different repetition numbers to be assigned to different preambles based on channel conditions, thereby improving transmission efficiency while maintaining manageable configuration complexity through structured organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic selection of repetition numbers by associating multiple preamble configurations with different repetition numbers (e.g., first preamble configuration with first repetition number, second preamble configuration with second repetition number). The UE can dynamically select the appropriate preamble configuration and repetition number based on channel quality indicators such as RSRP, transforming the static fixed repetition number approach into a dynamic adaptive approach that improves transmission efficiency.

Inventive Principle:
Principle #15Dynamics

2Loss of information

If a fixed repetition number is used for all preambles, then the signaling overhead is reduced, but the RACH procedure efficiency is degraded

Engineering Contradiction:
Improvesignaling overheadVSAvoidRACH procedure efficiency
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent applies local quality by assigning different repetition numbers to different preamble configurations based on local channel conditions. Instead of using a uniform repetition number across all preambles, the system allows each preamble configuration to have its own optimized repetition number, enabling efficient adaptation to local channel characteristics while minimizing unnecessary signaling overhead through targeted configuration.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the repetition number parameter dynamically by introducing multiple preamble configurations, each associated with a different repetition number. The system modifies the repetition number parameter based on channel quality measurements (such as RSRP thresholds), allowing the RACH procedure to adapt to varying channel conditions and improve efficiency without requiring excessive signaling overhead for configuration.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If multiple repetition numbers are supported for the same feature, then the transmission optimization is improved, but the configuration complexity is increased

Engineering Contradiction:
Improvetransmission optimizationVSAvoidconfiguration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent achieves universality by creating a multi-functional RACH configuration framework where multiple preamble configurations can coexist, each supporting different repetition numbers. This universal structure allows the same RACH procedure to handle various repetition scenarios (first repetition number, second repetition number) through a unified configuration mechanism, enabling transmission optimization across different channel conditions without requiring separate procedures for each repetition number.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies preliminary action by pre-configuring multiple preamble configurations with their respective repetition numbers before the actual RACH procedure. The network configures the UE with multiple preamble configurations in advance, each associated with a specific repetition number and RSRP threshold. This preliminary configuration allows the UE to quickly select the appropriate repetition number based on measured channel conditions without requiring complex real-time decision-making, thus improving transmission optimization while managing configuration complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4694521A1Method and device for transmission and reception of random access preamble in wireless communication system
Publication Date: 2026.02.11 LG ELECTRONICS INC
  • EP4694521A1 patent drawingFigure 1~2
  • EP4694521A1 patent drawingFigure 3(a)~3(b)
  • EP4694521A1 patent drawingFigure 4

AI summary

A method according to an embodiment of the present disclosure includes receiving a random access channel (RACH) configuration, and transmitting a random access preamble based on a repetition number related to a feature combination. The RACH configuration includes a plurality of preamble configurations. Each of the plurality of preamble configurations is related to one feature combination. The repetition number is one of a plurality of repetition numbers based on the plurality of preamble configurations.