PUCCH Repetition for Reliable NTN Initial Access

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Solution Overview

Problem

In non-terrestrial network (NTN) systems, the current transmission mechanism for the initial access phase fails to successfully transmit a physical uplink control channel (PUCCH), leading to initial access failures and reduced coverage performance due to limited coverage.

Innovation Solution

Introduce a repetition of PUCCH transmission in the initial access phase, allowing the terminal device to repeatedly transmit the PUCCH, improving the initial access success rate and coverage performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single transmission of PUCCH is used in the initial access phase, then the transmission mechanism is simple, but the coverage performance and initial access success rate are limited

Engineering Contradiction:
Improveinitial access success rateVSAvoidtransmission mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements periodic repetition of PUCCH transmissions at defined intervals (e.g., every 4, 8, or 16 slots) during the initial access phase. This periodic transmission strategy allows the UE to send multiple copies of the same uplink control information across different time resources, significantly improving coverage performance and access success rate in NTN scenarios without requiring complex adaptive modulation or power control mechanisms

Inventive Principle:
Principle #19Periodic action

2Reliability

If PUCCH repetition is introduced in the initial access phase, then coverage performance improves, but the transmission time and resource consumption increase

Engineering Contradiction:
Improvecoverage performanceVSAvoidtransmission time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent dynamically configures the PUCCH repetition interval and number of repetitions based on network conditions and UE requirements. The network can adjust the repetition parameter via RRC signaling or MAC CE, allowing the system to adapt between aggressive repetition (for poor coverage) and minimal repetition (for good coverage), thereby optimizing the trade-off between coverage enhancement and transmission time

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the transmission parameter by introducing a repetition factor that multiplies the number of PUCCH transmissions. By adjusting this parameter, the system can scale the coverage enhancement level without fundamentally changing the transmission protocol structure, allowing flexible optimization between coverage performance and time consumption based on specific NTN scenario requirements

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4503486B1Wireless communication methods, terminal devices, and network devices
Publication Date: 2025.10.29 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4503486B1 patent drawingFigure 1~2
  • EP4503486B1 patent drawingFigure 3~4
  • EP4503486B1 patent drawingFigure 5~7

AI summary

Embodiments of this application provide a wireless communications method, a terminal device, and a network device. The method includes: repeatedly transmitting a first physical uplink control channel PUCCH to a network device in an initial access phase. In this application, a repetition of PUCCH transmission is introduced in an initial access phase, which can improve an initial access success rate, and further improve coverage performance. Particularly, in a communication scenario in which coverage performance is limited, for example, in an NTN system, the repetition of PUCCH transmission is introduced in the initial access phase, so that the terminal device can successfully transmit the PUCCH for the initial access phase, thereby improving an initial access success rate and coverage performance.