Wireless Terminal Timing Correction for Moving Base Stations
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Solution Overview
Problem
Existing mobile communication systems face challenges in maintaining effective timing and frequency corrections, especially when both the wireless terminal and base station are in motion, as they often rely on pre-programmed base station location information, which is not feasible for all scenarios, including mobile base stations and unknown or unanticipated network interactions.
Innovation Solution
The system determines the position of a moving base station and uses this information to calculate timing and frequency corrections, considering the relative motion between the base station and wireless terminal, allowing for dynamic adjustments to compensate for Doppler shift and changes in signal propagation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pre-programmed base station location information is used, then timing and frequency corrections can be made, but the system cannot support mobile base stations or unknown network interactions
Solution Approach 1:
The patent transforms the static pre-programmed base station location information into dynamic real-time position determination. The wireless terminal actively determines the base station's current position through signal processing and calculation, allowing the system to adapt to mobile base stations and unknown network interactions without requiring prior programming of location data.
Solution Approach 2:
The wireless terminal performs self-service by autonomously determining base station position and calculating timing/frequency corrections without relying on pre-programmed information. The terminal uses received signals to compute relative position and motion, enabling the system to support any base station regardless of whether its location was known at deployment time.
2Reliability
If fixed known base station locations are assumed, then timing corrections can be calculated, but the system fails when base stations are in motion
Solution Approach 1:
The patent makes the base station position dynamic rather than fixed. By continuously determining the base station's current position and calculating relative motion between the terminal and base station, the system maintains reliable communication even when both parties are in motion, eliminating the limitation of fixed location assumptions.
Solution Approach 2:
The system uses feedback from signal processing to continuously update the relative position and motion calculations. By monitoring the received signals and recalculating timing and frequency corrections based on current relative motion, the system adapts to changing conditions and maintains communication reliability in mobile scenarios.
3Adaptability or versatility
If pre-programming with all terrestrial base station locations is attempted, then complete coverage is achieved, but memory constraints make it impractical
Solution Approach 1:
The wireless terminal performs self-service by autonomously determining base station positions rather than storing them. This eliminates the need for large memory resources to store location data for all possible base stations, while still achieving complete coverage and adaptability to any base station in the network.
Solution Approach 2:
The patent extracts the base station location information from the pre-programmed memory and obtains it dynamically through real-time signal processing and position calculation. This removes the memory burden while maintaining the ability to communicate with any base station, as the position is determined on-demand rather than stored in advance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables reliable communication by reducing the need for frequent correction signals and supports communication between mobile base stations and wireless terminals, even when their locations are not pre-programmed, improving synchronization and frequency accuracy in dynamic environments.
Implementation Method 1
Motion can also introduce frequency errors which are the result of Doppler shift which occurs due to motion and changes in relative distance between the base station and wireless terminal during the transmission process
Data Source
AI summary
A wireless terminal determines the position of a moving base station and determines timing and/or frequency corrections. A wireless terminal determines its relative position with respect to the base station and determines a timing adjustment correction. The wireless terminal applies the determined timing correction to control uplink signaling timing and achieve synchronization at the base station's receiver. The wireless terminal determines its relative velocity with respect to the moving base station and determines a Doppler shift adjustment which it adds to the uplink carrier frequency or to its baseband signal. Base station position is determined from the current time and stored information correlating the base station position with time, e.g., for a geo-synchronous satellite. Base station position information, e.g., a GPS derived base station position fix, is determined from downlink airlink broadcast information, e.g., for an aircraft base station. Wireless terminals may be mobile and include a GPS receiver for wireless terminal position determination.