Upstream Timing Control for Satellite Mobility in Non-Terrestrial Networks
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Solution Overview
Problem
Existing timing control mechanisms for terrestrial wireless networks are ineffective for non-terrestrial networks due to large propagation delays and satellite mobility, leading to significant timing errors and increased latency.
Innovation Solution
A wireless communications system for non-terrestrial networks that includes a base station, user equipment (UE), and a satellite, where the UE determines an initial timing adjustment based on satellite information, and the base station provides closed-loop feedback through timing commands to reduce timing errors, using group control information or dedicated physical channel messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If terrestrial wireless network timing control techniques are used, then timing control is simplified, but timing errors increase significantly due to large propagation delays and satellite mobility
Solution Approach 1:
The patent implements dynamic timing adjustment mechanisms that continuously adapt to changing propagation conditions. The base station dynamically determines timing adjustments based on current satellite position, velocity, and propagation delay measurements, allowing the system to maintain timing accuracy despite satellite mobility and varying network conditions.
Solution Approach 2:
The patent employs feedback mechanisms where the base station measures actual timing errors in upstream transmissions and uses this information to determine corrective timing adjustments. The base station transmits timing command messages to UEs based on measured timing errors, creating a closed-loop control system that continuously refines timing accuracy.
2Area of stationary object
If propagation delay is large in non-terrestrial networks, then communication coverage is extended, but timing errors and latency increase
Solution Approach 1:
The patent applies preliminary timing adjustments based on predicted propagation delays. The base station determines timing adjustments in advance using satellite ephemeris data and predicted positions, allowing upstream transmissions to be timed correctly before the actual communication occurs. This proactive approach compensates for the large propagation delays inherent in satellite communications.
Solution Approach 2:
The patent changes timing parameters dynamically based on measured propagation delays and satellite conditions. The base station adjusts timing parameters such as timing advance values and transmission scheduling based on current network conditions, optimizing communication timing to reduce latency while maintaining coverage.
3Measurement precision
If timing adjustments are continuously refined through closed-loop feedback, then timing accuracy improves, but system complexity increases
Solution Approach 1:
The base station performs self-measurement of timing errors using locally available information such as satellite ephemeris data and observed transmission characteristics. This self-service capability allows the base station to determine timing adjustments independently without requiring complex external synchronization systems, reducing overall system complexity while maintaining accuracy.
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AI summary
Methods, systems, and devices for wireless communications that support upstream timing control mechanisms for non-terrestrial networks are described. Generally, the described techniques provide for wireless communications from a user equipment (UE) in wireless communication with a satellite. A gateway in the non-terrestrial networks may receive an upstream transmission from the UE in wireless communication with the satellite and determine a timing adjustment for a second upstream transmission from the UE based on the upstream transmission from the UE. The gateway may then transmit to the UE in a group control information message or a dedicated physical channel message, a timing command indicating the timing adjustment for the second upstream transmission. The UE may receive the second timing adjustment and transmit data over the second upstream transmission using the second timing adjustment.