Base Station Timing Derivation from Wireless Terminal Data
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Solution Overview
Problem
In wireless telecommunications systems where base stations are not synchronized to a common time reference, determining the relative timing of events across multiple base stations is challenging, hindering services that require precise timing, such as position determination services based on time-difference of arrival (TDOA) techniques.
Innovation Solution
An attribute server generates time offset values for each base station using an iterative process involving trilateration and least-squares methods, refining these values to achieve accurate timing information across unsynchronized base stations, enabling improved timing accuracy for position determination services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If base stations use independent clocks without synchronization to a common time reference, then device complexity and ease of operation are improved (no complex synchronization infrastructure needed), but measurement precision of relative timing across base stations deteriorates
Solution Approach 1:
The patent introduces a data processing system that acts as an intermediary to collect timing information from multiple base stations and wireless terminals, perform iterative calculations using trilateration and least-squares methods, and derive relative timing relationships. This mediator process enables precise relative timing measurement without requiring complex hardware synchronization infrastructure between base stations.
2Reliability
If base stations are not synchronized to a common time reference, then ease of operation is improved (independent operation), but reliability of timing-dependent services deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the data processing system continuously collects timing information from base stations and wireless terminals, calculates predicted coordinates using current time offset values, compares them with reference coordinates, and iteratively refines the time offset values. This feedback loop ensures reliable timing-dependent services while maintaining base station operational independence.
3Measurement precision
If iterative refinement of time offset values is performed using trilateration and least-squares methods, then measurement precision of timing information is improved, but productivity of the processing system deteriorates (computational complexity)
Solution Approach 1:
The patent applies partial iteration by performing a predetermined number of refinement iterations or stopping when convergence criteria are met (when coordinate differences fall below a threshold). This approach achieves sufficient timing precision without performing excessive computational iterations, balancing measurement precision with processing efficiency.
Data Source
AI summary
A technique for deriving timing information across wireless base stations is disclosed. After initializing values for base station time-offset parameters, a server acquires reference coordinates of a wireless terminal, which are provided from an independent source, and also acquires values for one or more time-of-occurrences of events associated with signals that travel between the wireless terminal and the base stations. The server generates predicted coordinates of the wireless terminal, based in part on the current time-offset values, by using trilateration. The server then generates updated time-offset values, based on a method of least squares, in which each residual is a difference between the reference and predicted coordinates of each wireless terminal location, for one or more wireless terminals. The server modifies the time-offset values so as to minimize the least-squares function.