Random Access Channel Resource Allocation for NTN Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Non-Terrestrial Networks (NTNs) such as those utilizing satellites and airborne vehicles, the challenge of effectively supporting random access from multiple UEs with varying elevation angles and propagation delays leads to issues with PRACH performance due to time and frequency synchronization problems, particularly in 2-step RACH procedures.
Innovation Solution
The solution involves dividing the coverage area of a beam into sub-areas based on location, time, or frequency offsets, ensuring UEs in the same sub-area share the same RACH occasions (ROs) to reduce synchronization issues, and implementing 2-step and 4-step RACH procedures based on UE capabilities and indicated resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coverage area is divided into sub-areas based on location, time, or frequency offsets, then time and frequency synchronization among UEs is improved, but device complexity increases
Solution Approach 1:
The patent divides the coverage area into multiple sub-areas based on location, time, or frequency offsets. This segmentation allows UEs within the same sub-area to share common RACH occasions, thereby improving time and frequency synchronization. The segmentation principle directly addresses the synchronization reliability issue while managing complexity through structured division of the coverage area.
2Loss of time
If 2-step RACH procedure is implemented, then random access delay is reduced, but PRACH performance deteriorates due to synchronization issues
Solution Approach 1:
The patent segments the coverage area into sub-areas that share common RACH occasions. This segmentation enables the implementation of 2-step RACH procedure by ensuring that UEs within the same sub-area have synchronized timing and frequency, thereby reducing random access delay while maintaining PRACH performance. The segmentation resolves the contradiction by creating manageable groups that can support faster access procedures.
Solution Approach 2:
The patent applies local quality by assigning different RACH occasions to different sub-areas based on their specific location, time, or frequency characteristics. This allows each sub-area to have optimized access parameters tailored to its local conditions, enabling 2-step RACH in synchronized sub-areas while maintaining overall system reliability.
3Adaptability or versatility
If multiple RACH occasions are configured for different sub-areas, then adaptability to varying elevation angles and propagation delays is improved, but signaling overhead increases
Solution Approach 1:
The patent segments the coverage area into sub-areas, each associated with specific RACH occasions optimized for particular elevation angles and propagation delays. This segmentation provides adaptability to varying UE conditions while managing signaling overhead through structured configuration. Each sub-area's RACH occasion is configured once and reused by all UEs in that sub-area, reducing the need for individual UE-specific signaling.
Solution Approach 2:
The patent implements universality by making RACH occasions shared across multiple UEs within the same sub-area. A single RACH occasion configuration serves multiple purposes for different UEs with similar location, time, or frequency characteristics. This multi-functionality reduces signaling overhead compared to configuring separate RACH occasions for each UE while maintaining adaptability to varying elevation angles and propagation delays.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Systems and methods for wireless communications are disclosed herein. In some embodiments, a wireless communication method includes indicating, by a base station to a wireless communication device, at least one set of resources for network access and performing, by the base station, a network access procedure with the wireless communication device based on the at least one indicated set of resources for network access.