A-GPS Pre-scaling for Confidence Level Fulfillment
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Solution Overview
Problem
The 3GPP W-CDMA standard lacks clear specifications on how uncertainty and probability are related in Assisted GPS (A-GPS) positioning, leading to issues with confidence levels and quality-of-service (QoS) fulfillment, particularly in North American E-911 positioning, where the RNC scales up accuracies to meet higher confidence levels, resulting in failure to meet original accuracy requirements.
Innovation Solution
Introducing pre-scaling functionality to adjust horizontal and vertical accuracy requirements before sending them to mobile terminals, based on estimated confidence values and service types, ensuring the requested positioning accuracy is scaled according to the confidence level needed by the end user.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RNC scales up accuracy requirements to meet higher confidence levels (e.g., 95% for E-911), then the confidence level requirement is satisfied, but the original positioning accuracy requirement cannot be met
Solution Approach 1:
The patent applies preliminary action by pre-scaling the accuracy requirements before they are sent to the mobile terminal. The RNC calculates a pre-scale value based on the estimated confidence value and required confidence value, then applies this scaling factor to the accuracy requirements in advance. This allows the terminal to compute positioning results that will satisfy the final confidence level requirement without the RNC needing to scale up the accuracy afterward, thus preserving the original positioning accuracy capability.
2Productivity
If the RNC forwards accuracy requirements unchanged to the terminal, then the terminal can compute positioning results efficiently, but the QoS may not be fulfilled due to mismatched confidence levels
Solution Approach 1:
The patent applies parameter changes by modifying the accuracy requirement parameters based on confidence level calculations. The RNC determines a pre-scale value using the formula involving the estimated confidence value and required confidence value, then applies this scaling factor to transform the accuracy requirements. This parameter transformation ensures that when the terminal computes positioning results with the scaled requirements, the final QoS metrics will be satisfied while maintaining computational efficiency.
3Ease of operation
If the RNC performs shape conversion to scale accuracies to configured confidence levels, then the reported accuracy matches the service configuration, but the original requested accuracy from the end user is not achieved
Solution Approach 1:
The patent resolves this contradiction by performing the scaling action preliminarily, before sending requirements to the terminal. By calculating and applying the pre-scale value in advance based on the relationship between estimated and required confidence levels, the system ensures that the terminal's positioning computation directly produces results meeting the original end-user accuracy requirements, while the RNC can still perform any necessary shape conversions for service compliance without degrading the achieved accuracy.
Data Source
AI summary
A method in conjunction with positioning of a mobile terminal in a cellular telecommunication system is disclosed. According to the method, an end user's requested positioning accuracy for the positioning of the mobile terminal is determined (510). Also, an estimated confidence value for the positioning of the mobile terminal is determined (520), and so is a required confidence value for the end user (530). Then, a pre-scale value is produced (540) based on at least the estimated confidence value and the required confidence value. The pre-scale value is applied (550) to the requested positioning accuracy to obtain a pre-scaled requested positioning accuracy. Then, the pre-scaled requested positioning accuracy is sent (560) in the cellular telecommunication system towards the mobile terminal.