Cross-TRP Random Access Using PDCCH Target TRP Indication

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Solution Overview

Problem

Existing communication systems face challenges in efficiently performing random access procedures across multiple transmission and reception points (TRPs) in environments with limited line-of-sight paths, requiring improved methods for identifying and communicating with target TRPs during random access operations.

Innovation Solution

A method and apparatus for cross-TRP random access involving a user equipment (UE) receiving a cross-physical downlink control channel (PDCCH) order to identify a target TRP and transmit a random access preamble, utilizing timing advance group (TAG) identifiers, transmission configuration indicator (TCI) states, and cell identifiers to facilitate communication with a second TRP different from the first.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a terminal transmits an RA preamble to a first TRP based on a PDCCH order from the first TRP, then the random access procedure can be performed, but it cannot achieve cross-TRP random access when communication with the second TRP is required

Engineering Contradiction:
Improvecross-TRP random access capabilityVSAvoidrandom access procedure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the random access procedure by introducing separate indication information for the target TRP identity within the PDCCH order. This allows the terminal to independently identify whether to access the first or second TRP, enabling cross-TRP random access while maintaining clear procedural separation and avoiding overall complexity increase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a new dimension to the PDCCH order by including target TRP identity indication information. This additional dimension enables the terminal to determine the appropriate target TRP for random access, transforming a single-TRP access mechanism into a multi-TRP capable mechanism without fundamentally changing the existing procedure structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If indication information for target TRP identity is added to the PDCCH order, then cross-TRP random access is enabled, but the signaling overhead increases

Engineering Contradiction:
Improvecross-TRP random access capabilityVSAvoidsignaling overhead
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies local quality by making the target TRP identity indication information conditional - it is only included in the PDCCH order when cross-TRP random access is required. This selective inclusion minimizes signaling overhead while maintaining the capability for cross-TRP access when needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses partial action by including only the necessary target TRP identity information in the PDCCH order rather than complete TRP configuration data. This partial information approach enables cross-TRP access functionality while keeping the signaling overhead minimal.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4723759A1Method and device for cross-TRP random access
Publication Date: 2026.04.08 HYUNDAI MOTOR CO LTD
  • EP4723759A1 patent drawingFigure 1
  • EP4723759A1 patent drawingFigure 2
  • EP4723759A1 patent drawingFigure 3

AI summary

Disclosed are a method and device for cross-TRP random access. The method performed by a UE comprises the steps of: receiving a cross-PDCCH order from a first TRP; identifying a second TRP on which to perform an RA procedure, the second TRP being identified on the basis of first indication information included in the cross-PDCCH order; and transmitting a message including an RA preamble to the second TRP, wherein the first TRP and the second TRP are different TRPs.