Emergency Circuit-Mode Call Routing via SUPL Positioning
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Solution Overview
Problem
Existing wireless communication networks face challenges in routing emergency calls to the appropriate Public Safety Answering Point (PSAP) for both subscribed and unsubscribed users, especially when users are roaming, as they lack efficient mechanisms for obtaining accurate location estimates and routing emergency circuit-mode calls.
Innovation Solution
The implementation of techniques that utilize a combination of control plane and user plane solutions, specifically employing SUPL (Secure User Plane Location) and X.S0024 location services, to enable User Equipments (UEs) to establish emergency circuit-mode calls by interacting with location servers for position estimation and routing, even without a service subscription, across various 3GPP and 3GPP2 networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional control plane solutions are used for emergency call routing, then call establishment is supported, but accurate location estimation for roaming and unregistered users cannot be obtained
Solution Approach 1:
The patent combines control plane and user plane solutions to enable emergency call routing. The control plane establishes the emergency call connection while the user plane (SUPL protocol) simultaneously provides accurate location estimation through interaction between the UE and location server, resolving the limitation of traditional control plane-only approaches that cannot provide location data for roaming and unregistered users
Solution Approach 2:
The patent introduces a location server as an intermediary entity that facilitates location estimation for emergency calls. The location server receives positioning requests from the network, interacts with the UE using SUPL protocol to obtain position data, and returns the location information to enable accurate PSAP routing, thereby mediating between the network's routing needs and the UE's location capabilities
2Measurement precision
If user plane location solutions (SUPL) are implemented for emergency calls, then accurate position estimates can be obtained, but the implementation complexity increases
Solution Approach 1:
The patent segments the emergency call handling into distinct functional components: control plane for call establishment and user plane for location estimation. This segmentation allows each plane to operate independently with optimized protocols, reducing overall system complexity while maintaining high position estimate accuracy through specialized SUPL processing
Solution Approach 2:
The patent performs location estimation activities in parallel with call establishment rather than sequentially. The UE initiates SUPL positioning sessions concurrently with emergency call setup, obtaining position estimates before PSAP routing decisions are finalized, thereby eliminating additional delays and reducing implementation complexity
3Productivity
If emergency calls are routed based on interim position estimates, then call routing can proceed, but updated location information may not be available when requested by PSAP
Solution Approach 1:
The patent maintains continuous location estimation capability throughout the emergency call duration. The SUPL positioning session remains active during the call, allowing the network to request updated position estimates from the UE whenever the PSAP needs current location information, ensuring continuous availability of accurate position data without interrupting the emergency call service
Data Source
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AI summary
Techniques to support emergency circuit-mode calls are described. The techniques may be used for various 3GPP and 3GPP2 networks, various location architectures, and various types of User Equipment (UE). A UE establishes a circuit-mode call with a wireless network for emergency services. The UE interacts with a location server indicated by the wireless network. The UE performs user plane location with the location server during the circuit-mode call to obtain a position estimate for the UE. The UE communicates with a PSAP, which may be selected based on the position estimate, for the emergency circuit-mode call. The UE may perform positioning with the location server to obtain an updated position estimate for the UE, e.g., whenever requested by the PSAP.