Uplink Timing Adjustment in NTN Communications
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Solution Overview
Problem
In Non-Terrestrial Networks (NTN), the long propagation delay between satellites or aircraft and User Equipment (UE) poses challenges for uplink timing adjustment, as existing Timing Advance (TA) configurations designed for terrestrial communications are inadequate, leading to potential interference and increased scheduling complexity.
Innovation Solution
A method where the UE independently determines timing adjustments based on candidate timing adjustments, using real-time information such as moving speed, geographical position, and crystal-oscillator offset, to ensure timely uplink synchronization, thereby avoiding the limitations of network-side TA configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If network equipment configures Timing Advance for uplink transmissions in NTN, then uplink synchronization is maintained, but the TA adjustment signaling cannot reflect uplink synchronization status in time due to very large propagation delay
Solution Approach 1:
The network equipment pre-calculates and configures a set of candidate TA values to the UE before the UE actually needs them. This preliminary provision of timing adjustment options allows the UE to quickly select and apply appropriate TA values without waiting for network signaling during critical timing adjustments, thus reducing the effective latency while maintaining synchronization reliability
Solution Approach 2:
The patent introduces dynamic TA adjustment where the UE can autonomously select from multiple candidate TA values based on current propagation conditions. This dynamic selection mechanism enables the system to adapt quickly to changing timing requirements in NTN environments with large propagation delays, overcoming the static and slow network-configured TA approach
2Device complexity
If existing TA configuration designed for terrestrial communications is applied to NTN, then system complexity is reduced, but uplink interference increases due to inadequate timing adjustment
Solution Approach 1:
The TA configuration is segmented into multiple candidate values rather than using a single TA value as in terrestrial communications. This segmentation allows the system to provide a range of timing adjustments suitable for different propagation delays in NTN, enabling fine-grained timing control that reduces uplink interference while maintaining manageable complexity through structured candidate sets
Solution Approach 2:
The patent changes the TA parameter from a single network-configured value to a set of candidate values that the UE can select from. This parameter transformation enables the system to adapt to the varying propagation conditions in NTN without requiring completely new complex configuration mechanisms, thus reducing interference while controlling complexity
Data Source
AI summary
The present disclosure provides a method and a device in a communication node for wireless communications. The communication node in the present disclosure first receives first information, and then transmits a first radio signal; a length of a time interval between a start time for transmitting the first radio signal and a first reference time is equal to a sum of a first timing adjustment and a second timing adjustment, the first timing adjustment being one of X candidate timing adjustments, the X being a positive integer greater than 1; the second timing adjustment is used for determining a transmission timing of a radio signal transmitted before the first radio signal in time domain; a transmitter of the first radio signal determines the first timing adjustment out of the X candidate timing adjustments by itself. The present disclosure can improve uplink synchronization performance.