Timing Advance Determination with Error Compensation
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Solution Overview
Problem
In satellite communication, the high round-trip delay causes timing advance errors, leading to intersymbol interference during the random access process due to positioning and ephemeris errors, resulting in inefficient transmission.
Innovation Solution
A method to determine timing advance by considering the positioning error of the terminal device and ephemeris error of the satellite, using specific rules based on horizontal and vertical distances, errors, and light speed constant, to ensure the random access preamble reaches the satellite within the correct time period, thereby avoiding intersymbol interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If timing advance is calculated based on location and ephemeris information, then the terminal device can send random access preamble in advance, but positioning error and ephemeris error cause timing advance error leading to intersymbol interference
Solution Approach 1:
The patent changes the parameters used for timing advance calculation by introducing a compensation value that accounts for positioning error and ephemeris error. Instead of using only location and ephemeris information, the calculation incorporates error compensation parameters to adjust the timing advance value, thereby maintaining accuracy while still enabling early transmission.
Solution Approach 2:
The patent replaces the simple geometric calculation method (based solely on distance and speed of light) with a corrected calculation mechanism that substitutes error-prone direct calculation with an error-compensated approach. This substitution introduces a correction layer that accounts for systematic errors in positioning and ephemeris data.
2Reliability
If timing advance is adjusted to account for positioning and ephemeris errors, then intersymbol interference is avoided, but calculation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating or pre-obtaining the compensation value for positioning and ephemeris errors. This compensation value is determined in advance and stored or prepared before the actual timing advance calculation, allowing the terminal device to simply add this pre-computed correction to the basic timing advance without performing complex real-time error analysis.
Solution Approach 2:
The patent extracts the error compensation component as a separate, independent parameter from the main timing advance calculation. By separating the compensation value from the core distance-based calculation, the system handles errors independently, simplifying the overall structure while improving accuracy.
Data Source
AI summary
Example methods and apparatus for determining a timing advance are described. One example method includes obtaining ephemeris information of a satellite, where the ephemeris information includes coordinates of the satellite and an ephemeris error of the satellite. A timing advance is determined according to a preset rule based on the ephemeris information and location information of a terminal device, where the location information includes coordinates of the terminal device and a positioning error of the terminal device. The preset rule is determined by using a first horizontal distance, a first vertical distance, the ephemeris error, and the positioning error.