Random Access Resource Selection for NTN Access Conflict Avoidance
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Solution Overview
Problem
In non-terrestrial networks, existing technologies fail to address the issue of terminals initiating random access at the same time due to shared uplink synchronization auxiliary information epoch times, leading to access conflicts.
Innovation Solution
The method involves determining the transmission resource of the first message based on the time difference between a first time and a second time, where the first time is determined based on system information and the second time is determined based on the epoch time of uplink synchronization auxiliary information, thereby preventing terminals from initiating random access at the same time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terminals use the same effective timepoint for uplink synchronization auxiliary information, then uplink synchronization is achieved, but terminals initiate random access at the same time causing access conflicts
Solution Approach 1:
The patent segments the random access initiation time by introducing a first timepoint based on system information reception time and a second timepoint based on effective timepoint. The terminal determines the transmission resource based on the time difference between these two timepoints, thereby segmenting the access timing to avoid conflicts while maintaining synchronization.
Solution Approach 2:
The patent applies preliminary action by having the terminal determine the first timepoint based on system information reception before using it for random access initiation. The terminal calculates the time difference between the first timepoint and second timepoint in advance to determine the appropriate transmission resource, preventing simultaneous access before it occurs.
2Reliability
If terminals select the first RACH occasion after the effective timepoint, then uplink synchronization is maintained, but terminals searching at different times collide at the same RACH occasion
Solution Approach 1:
The patent introduces dynamic timing adjustment by making the random access initiation time dependent on the time difference between the first timepoint (system information reception) and the second timepoint (effective timepoint). This dynamic approach allows terminals to stagger their access attempts while maintaining synchronization, improving both reliability and productivity.
3Device complexity
If the same effective timepoint is configured for all terminals, then network configuration is simplified, but access conflicts increase
Solution Approach 1:
The patent enables terminals to autonomously determine their own access timing based on their individual system information reception times. Each terminal calculates the time difference between its first timepoint and the second timepoint independently, allowing self-service timing adjustment without complex network configuration while reducing access conflicts.
Data Source
AI summary
A random access method is performed by a terminal and includes: determining, based on a time difference between a first timepoint and a second timepoint, a resource for sending a first message, wherein the first timepoint is determined based on system information (SI) received by the terminal, the second timepoint is determined based on an effective timepoint of uplink synchronization auxiliary information received by the terminal, and the first message is used for initiating random access.