NTN Cell Signaling for Delay-Tolerant Random Access
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Solution Overview
Problem
In the New Radio (NR) system, the large distance between a satellite and the ground in Non-Terrestrial Networks (NTN) results in high signal transmission delay, making it difficult for terminal devices to use a random access scheme for NTN cells, necessitating a solution to distinguish cell types for proper access.
Innovation Solution
A network device indicates the type of a cell via first signaling, allowing a terminal device to select an appropriate random access scheme, thereby improving the success rate of access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal device uses a random access scheme for Terrestrial Networks (TN) to access an NTN cell, then the access procedure follows the conventional TN protocol, but the success rate of random access is low due to high signal transmission delay caused by the large distance between satellite and ground
Solution Approach 1:
The patent changes the access parameters by introducing NTN-specific random access configurations that account for the high transmission delay. The network device configures different random access parameters for NTN cells compared to TN cells, including adjusted timing advance values and random access resource allocations that compensate for the satellite distance-induced delay, thereby improving access success rate despite the inherent time loss.
Solution Approach 2:
The patent segments the random access procedure into NTN-specific and TN-specific paths by introducing cell type identification. The terminal device first identifies whether it is accessing an NTN cell or TN cell, then selects the appropriate random access scheme. This segmentation allows the system to apply delay-tolerant access protocols for NTN while maintaining conventional protocols for TN, resolving the contradiction between using TN protocols and achieving reliable NTN access.
2Adaptability or versatility
If the terminal device does not distinguish cell types, then the access procedure is simple, but the terminal device cannot select the appropriate random access scheme for NTN cells
Solution Approach 1:
The patent applies preliminary action by having the network device pre-configure and indicate cell type information before the terminal device attempts random access. The network device sends indication information (such as physical layer signaling or higher layer signaling) that identifies the cell as NTN or TN. This preliminary identification allows the terminal device to select the appropriate access scheme without adding complex real-time decision-making, as the cell type is already known from prior signaling.
3Measurement precision
If the network device provides detailed cell type indication information, then the terminal device can accurately identify NTN cells and select the correct access scheme, but the signaling overhead increases
Solution Approach 1:
The patent uses an intermediary approach by leveraging existing cell identification mechanisms (such as Physical Cell ID or synchronization signal block information) that already exist in the system. Instead of introducing entirely new detailed indication messages, the network device utilizes or extends existing signaling fields to convey NTN cell identification. This intermediary use of existing infrastructure provides accurate cell type identification while minimizing additional signaling overhead.
Data Source
AI summary
The present disclosure provides a wireless communication method, a terminal device, and a network device. The method includes: receiving, by a terminal device, first signaling transmitted by a network device, the first signaling being used to determine whether a target cell is a Non-Terrestrial Network (NTN) cell. The network device can indicate a type of a cell via first signaling, such that the terminal device can select an appropriate random access scheme to perform random access according to the type of the cell, thereby improving the success rate of the random access.