PDCCH Repetition Control for Random Access With Multiple TCI States

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing control channel repetitions for random access procedures, particularly in environments with multiple transmission configuration indicator (TCI) states, leading to suboptimal performance and reliability.

Innovation Solution

A method for wireless devices and base stations that involves receiving a physical downlink control channel order through a control resource set activated with multiple TCI states, transmitting a random-access preamble, and receiving downlink control information based on these TCI states to enhance the random-access response, thereby improving the reliability and efficiency of control channel repetitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If control channel repetitions are managed in existing wireless communication systems, then coverage and reliability are improved, but system complexity and resource overhead increase

Engineering Contradiction:
Improverandom access reliabilityVSAvoidcontrol channel management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of TCI state indication by introducing a specific field in DCI format 1_0 that indicates which TCI state among multiple activated states should be used for PDCCH reception. This parameter change enables the system to select appropriate TCI states dynamically without increasing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the control channel reception process by separating the activation of multiple TCI states from the selection of active TCI state. The MAC CE activates multiple TCI states while the DCI field selects which one to use, dividing the complex management into manageable segments.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple TCI states are activated for control resource set, then control channel repetition performance is improved, but processing overhead and signaling complexity increase

Engineering Contradiction:
Improvecontrol channel repetition performanceVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent makes the DCI format 1_0 multi-functional by adding a versatile field that serves dual purposes: indicating TCI state for PDCCH reception and enabling the UE to identify which repetition instance it is receiving. This single field handles multiple functions without requiring separate signaling.

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

Solution Approach 2:

The patent uses a compact copy of TCI state information in the DCI field rather than transmitting full TCI state configurations repeatedly. The field contains essential identification information that references the activated TCI states, reducing signaling overhead while maintaining functionality.

Inventive Principle:
Principle #26Copying

3Reliability

If random access response scheduling uses multiple TCI states, then access reliability is improved, but device processing complexity increases

Engineering Contradiction:
Improverandom access response reliabilityVSAvoiddevice processing ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent enables the UE to self-determine which TCI state to use by providing clear indication through the DCI field. The UE autonomously selects the appropriate TCI state based on the indication without requiring complex network coordination or additional processing steps.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4205459B1Methods, devices and system for random access in control channel repetition
Publication Date: 2025.07.09 OFINNO LLC
  • EP4205459B1 patent drawingFigure 1A~1B
  • EP4205459B1 patent drawingFigure 2A~2B
  • EP4205459B1 patent drawingFigure 3

AI summary

A wireless device may receive, via a control resource set (coreset) activated with at least two transmission configuration indicator (TCI) states, a physical downlink control channel (PDCCH) order triggering a random-access procedure for a cell. The wireless device may transmit a random-access preamble, of the random-access procedure, with a transmission power based on a TCI state among the at least two TCI states of the coreset.