NTN Time Delay Compensation via Relative Link Parameters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Satellite communication systems face significant time delay challenges due to large propagation delays, making traditional terrestrial communication compensation methods inadequate, leading to complexity in UE hardware implementation and reduced timing accuracy in uplink processes.
Innovation Solution
Implementing time delay compensation based on relative time delays of the service and feeder links in satellite communication systems, using formulas like T3=(d3−d3_ref)/c and T4=(d4−d4_ref)/c, where d3 and d4 represent absolute distances, and d3_ref and d4_ref are reference distances obtained through methods such as ephemeris information or broadcast signaling, to calculate and compensate for time delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If absolute time delay compensation is used in satellite communication systems, then timing accuracy can be improved, but UE hardware implementation complexity increases significantly
Solution Approach 1:
The patent changes the compensation parameter from absolute time delay to relative time delay. The network side calculates relative time delay compensation values based on differences between actual and reference time delays, then notifies these values to UEs. This parameter transformation maintains timing accuracy while significantly reducing UE hardware complexity, as UEs only need to apply the notified compensation values without performing complex absolute time delay calculations.
2Reliability
If absolute time delay compensation is implemented, then synchronization reliability can be improved, but the overhead of CP and GT becomes excessively large
Solution Approach 1:
The patent transforms the compensation approach from absolute to relative time delay. By calculating compensation values as differences between actual and reference time delays, the system maintains synchronization reliability while reducing the magnitude of compensation values needed. This reduces the overhead of cyclic prefix and guard time, as relative time delays are smaller than absolute time delays in satellite communication scenarios.
3Device complexity
If traditional terrestrial communication compensation methods are used in satellite communication systems, then device complexity can be kept low, but timing accuracy and synchronization reliability deteriorate
Solution Approach 1:
The patent introduces relative time delay compensation values as an intermediary between the network side and UEs. The network side performs the complex calculation of relative time delays based on satellite ephemeris information and UE location, then notifies these pre-calculated values to UEs. This intermediary approach allows UEs to maintain low device complexity while achieving accurate timing synchronization, as they only need to apply the notified compensation values without performing complex calculations.
4Measurement precision
If absolute time delay compensation is used, then timing accuracy can be maintained, but the system becomes less adaptable to satellite communication scenarios
Solution Approach 1:
The patent adapts the time delay compensation mechanism to satellite communication by changing from absolute to relative time delay parameters. This parameter transformation makes the system adaptable to satellite scenarios with large and variable propagation delays. The relative time delay approach, which compensates for differences between actual and reference delays, works effectively across varying satellite positions and UE locations, providing both accuracy and adaptability.
Data Source
AI summary
Disclosed are a time delay compensation method and apparatus and a time delay control method and apparatus, which are used for performing time delay compensation on the basis of a relative time delay of a service link and a relative time delay of a feeder link. An uplink timing mechanism for an NTN system is provided, to ensure the reliability of a synchronization establishment process of the NTN system and the timing accuracy of a subsequent data transmission process. Provided is a time delay compensation method, comprising: determining that time delay compensation needs to be performed on a service link and a feeder link in a non-terrestrial networks (NTN) system; and performing time delay compensation on the basis of a relative time delay of the service link and a relative time delay of the feeder link.