E911 Call Positioning Using Carrier Aggregation and OTDOA
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Solution Overview
Problem
In urban environments and indoor/underground scenarios, GNSS signals are obstructed or reflected, leading to inaccurate location data or delays in determining the precise coordinates of a user equipment (UE) during emergency calls, necessitating improved positioning strategies.
Innovation Solution
Implement carrier aggregation using low and high frequency bands, enabling downlink beamforming operations and observed time difference of arrival (OTDOA) positioning to enhance location determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS is used for positioning, then positioning accuracy is improved in open environments, but positioning reliability deteriorates in urban environments and indoor scenarios due to signal obstruction and reflection
Solution Approach 1:
The patent introduces network-based positioning methods (OTDOA, E-CID) as intermediary solutions when GNSS is unavailable or unreliable. The location server acts as a mediator that coordinates positioning measurements between the UE and network infrastructure, providing alternative positioning paths that bypass the need for direct satellite signals in challenging environments.
Solution Approach 2:
The patent changes the positioning parameters from satellite-based (GNSS) to network-based measurements. By switching to uplink/downlink signal measurements between UE and base stations, the system adapts to environments where satellite signals are blocked, maintaining positioning capability through different physical measurement principles.
2Measurement precision
If carrier aggregation with high frequency bands is implemented, then positioning accuracy is improved through precise angle and time measurements, but signal degradation increases in challenging environments due to higher path loss
Solution Approach 1:
The patent merges multiple frequency bands (low/mid band and high band) using carrier aggregation. This combination allows the system to leverage the coverage advantages of low/mid bands and the positioning precision advantages of high bands simultaneously, achieving both reliable signal reception and accurate positioning measurements.
Solution Approach 2:
The patent applies different frequency bands for different purposes: low/mid frequency bands are used for general coverage and signal reliability, while high frequency bands are specifically utilized for positioning measurements where precision is critical. This local optimization of frequency band usage maximizes overall system performance.
3Measurement precision
If downlink beamforming is enabled for high frequency band, then positioning accuracy is enhanced through focused signal direction, but device complexity increases due to additional processing requirements
Solution Approach 1:
The location server acts as an intermediary that manages the complexity of beamforming operations. By centralizing the control and coordination of downlink beamforming at the network side, the patent reduces the processing burden on UE devices while still achieving the positioning accuracy benefits of focused signal direction.
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 significantly improves positioning accuracy by leveraging high-frequency signals' precise angle and time measurements, overcoming signal degradation in challenging environments.
Implementation Method 1
initiating observed time difference of arrival (OTDOA) positioning operations; determining a location of a communication device that initiated the emergency call based on the enabling of the downlink beamforming operations and the initiating of the OTDOA positioning operations
Implementation Method 2
enabling downlink beamforming operations in respect of the high frequency band
Data Source
AI summary
Aspects include obtaining a call request, determining that the call request is placed from an environment that suffers from location inaccuracy, resulting in a first determination, based on the first determination, determining, that a serving cell is operating at a low or mid frequency band and at least one high frequency band neighbor is available, resulting in a second determination, based on the second determination, initiating carrier aggregation in a downlink direction using the low or mid frequency band and a high frequency band included in the at least one high frequency band neighbor, enabling downlink beamforming operations in respect of the high frequency band, initiating observed time difference of arrival (OTDOA) positioning operations, and determining a location of a mobile communication device that initiated the call request based on the enabling of the downlink beamforming operations and the initiating of the OTDOA positioning operations. Other embodiments are disclosed.