Emergency Call Routing Using Cached and Fresh UE Location
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Solution Overview
Problem
Existing location-based routing systems for wireless emergency calls face delays due to the reliance on cached locations from global navigation satellite systems (GNSS) chips, which may not accurately reflect the current UE location, potentially leading to incorrect routing to a different Public Safety Answering Point (PSAP).
Innovation Solution
Implementing sensors in user equipment (UE) to determine if the location has changed beyond a threshold distance from a cached location, and if so, generating a fresh location via a SIPINV message to ensure accurate communication with the correct PSAP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cached location from GNSS chip is used for emergency call routing, then location availability is improved, but location accuracy deteriorates
Solution Approach 1:
The system performs preliminary actions by caching locations from location-based applications before emergency calls are made. This ensures location data is available in advance, improving availability while the system later validates accuracy through sensor-based movement detection to prevent routing errors.
Solution Approach 2:
The system implements feedback mechanisms by using sensors to detect UE movement and comparing current position against cached location. This feedback loop allows the system to determine when a fresh location is needed versus when the cached location remains valid, balancing availability with accuracy.
2Measurement precision
If fresh location is obtained via SIPINV message, then location accuracy is improved, but call setup time increases
Solution Approach 1:
The system applies partial action by obtaining location data through multiple sources (location-based applications, sensors, and SIPINV messages) rather than relying on a single source. This allows the system to use available cached locations for quick routing while supplementing with fresh data only when necessary, balancing speed and accuracy.
Solution Approach 2:
The system performs preliminary location caching from location-based applications before emergency calls are made. This preliminary action provides immediate location data for call routing, reducing setup time while the system maintains the capability to update with fresh locations via SIPINV messages when movement is detected.
3Measurement precision
If sensor-based movement detection is implemented, then routing accuracy is improved, but device complexity increases
Solution Approach 1:
The system applies universality by using the same sensor-based movement detection mechanism for multiple purposes: determining when to use cached locations, deciding when to request fresh locations via SIPINV messages, and validating location accuracy. This multi-functional approach improves routing accuracy without proportionally increasing complexity.
Solution Approach 2:
The system implements self-service by having the UE itself perform movement detection using its own sensors and automatically determine when location updates are needed. This self-service mechanism improves routing accuracy through local awareness of movement while avoiding the need for complex external monitoring systems.
Data Source
AI summary
Systems and methods are provided for enhancing availability of a user equipment (UE) location for location-based routing of a wireless emergency call. When an emergency call is initiated by UE, a distance of a current location of the UE to a cached location of the UE is determined. Based on the distance, a location of the UE is communicated to a gateway. The location, in various aspects either the cached location as determined by a location-based application executing on the UE or the current location communicated by the UE in a SIPINV message, enables the UE to initiate communication with the appropriate PSAP.