PUCCH Repetition Signaling for NTN Initial Access Coverage
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Solution Overview
Problem
The physical uplink control channel (PUCCH) for Msg4 HARQ-ACK in non-terrestrial networks (NTN) fails to meet coverage requirements due to the lack of support for PUCCH repetitions during initial access, leading to potential coverage issues with control channels.
Innovation Solution
Implementing a method where a user equipment (UE) requests PUCCH repetitions by utilizing a temporary cell radio network temporary identifier (TC-RNTI) different from the assigned one, allowing the network to recognize and accommodate PUCCH repetition capabilities during initial access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PUCCH repetitions are not supported during initial access, then the system maintains simplicity in resource configuration, but the coverage of PUCCH for Msg4 HARQ-ACK deteriorates and fails to meet NTN coverage requirements
Solution Approach 1:
The terminal performs preliminary action by selecting a specific PUCCH resource from the resource set that is configured for supporting repetitions, and indicates this selection through the PRI field in Msg4. This allows the network to pre-configure multiple PUCCH resources with different repetition parameters, and the terminal to choose the appropriate one before actual PUCCH transmission, thereby enabling coverage enhancement without complex real-time configuration
Solution Approach 2:
The invention changes the PUCCH configuration parameters by introducing a mechanism where different PUCCH resources in the resource set have different numbers of repetitions configured. The terminal selects a resource with appropriate repetition parameter based on coverage requirements, and indicates the selection via PRI. This parameter differentiation allows the system to adapt PUCCH repetition behavior to specific coverage needs while maintaining a standardized resource configuration framework
2Adaptability or versatility
If the network does not have information on UE capability for PUCCH repetitions during initial access, then the signaling overhead is reduced, but the adaptability to different UE requirements deteriorates
Solution Approach 1:
The terminal performs preliminary action by selecting a PUCCH resource that reflects its capability for repetitions and indicating this selection through the PRI field in Msg4. This allows the network to infer UE capability for PUCCH repetitions from the resource selection before formal capability exchange occurs during RRC setup, thereby making capability information available earlier in the access procedure
Solution Approach 2:
The PUCCH resource selection acts as an intermediary that conveys UE capability information indirectly. Instead of requiring explicit capability signaling, the terminal's choice of PUCCH resource (which has predetermined repetition characteristics) serves as a mediator that communicates the UE's repetition capability to the network through the PRI field, enabling the network to adapt its response accordingly
Data Source
AI summary
There are provided measures for control channel repetition management. Such measures exemplarily comprise receiving, from a terminal, a connection request message, checking whether said connection request message is scrambled utilizing any of at least one temporary identifier other than a temporary identifier assigned to said terminal, and, if said connection request message is scrambled utilizing any of said at least one temporary identifier, concluding that said terminal can make use of physical uplink control channel repetitions.