Emergency Services via Non-Cellular Wireless Access
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Solution Overview
Problem
There is a need for mechanisms to support access to emergency services sessions for wireless communication devices when roaming in a visited country/region, particularly in cases where the device lacks a SIM or eSIM, or when restricted from regular services, and not all Public Land Mobile Networks (PLMNs) support emergency services access via non-cellular wireless access networks.
Innovation Solution
The solution involves a wireless communication device querying a network-based server, such as a DNS server, to determine PLMNs and evolved Packet Data Gateways (ePDGs) that support emergency services in the visited country/region, selecting an appropriate ePDG, and obtaining local emergency services numbers to establish emergency services sessions via non-cellular wireless access networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wireless communication device roams in a visited country/region without a valid SIM or eSIM, then the device cannot access regular cellular services, but it still needs to access emergency services
Solution Approach 1:
The patent segments service access by creating separate pathways: regular services require SIM authentication while emergency services can access through alternative methods. The system divides emergency service access into multiple components including ePDG selection, PLMN identification, and local emergency number determination, allowing emergency services to function independently from regular cellular services.
Solution Approach 2:
The patent introduces intermediary mechanisms including DNS servers that mediate between the wireless device and the network infrastructure. The DNS server acts as an intermediary to resolve ePDG addresses and provide PLMN information, enabling emergency service access without direct SIM-based authentication. The ePDG itself serves as an intermediary gateway between non-cellular wireless access networks and the core network.
2Adaptability or versatility
If not all PLMNs support emergency services access via non-cellular wireless access networks, then the device cannot universally access emergency services, but restricting to only supporting PLMNs limits coverage
Solution Approach 1:
The patent implements dynamic ePDG selection based on real-time network conditions and device state. The wireless device dynamically queries DNS servers to obtain current ePDG addresses and PLMN information, allowing it to adapt to changing network availability. The system dynamically determines which PLMNs support emergency services in the visited country/region and selects appropriate ePDGs accordingly.
Solution Approach 2:
The patent changes key parameters including country code, PLMN identity, and ePDG address based on the device's location and network conditions. By querying DNS servers with location-specific information, the system retrieves updated parameters for emergency service access. The wireless device modifies its access parameters to match the characteristics of supporting PLMNs in the visited region.
3Ease of operation
If the device queries network servers to determine supporting PLMNs and ePDGs, then the device can find appropriate emergency services access points, but the process increases complexity and time required
Solution Approach 1:
The patent implements self-service mechanisms where the wireless device autonomously performs DNS queries to determine available ePDGs and PLMNs. The device independently processes the received information and makes selection decisions without requiring manual configuration or intervention. This self-service approach simplifies operation for the user while managing the complexity within the device's automated procedures.
Solution Approach 2:
The patent performs preliminary actions by pre-configuring the wireless device with capabilities to query DNS servers and process emergency service access information. The device prepares emergency service access parameters in advance, including the ability to determine country codes and query for supporting networks before actual emergency service needs arise. This preliminary preparation reduces the complexity during actual emergency access scenarios.
4Reliability
If the device establishes connections with ePDGs of supporting PLMNs, then the device can access emergency services, but the connection establishment process becomes more complex
Solution Approach 1:
The patent implements universal connection establishment procedures that work across multiple PLMNs and ePDGs. The wireless device uses a standardized approach to query DNS servers, select ePDGs, and establish connections that is applicable regardless of which specific PLMN or ePDG is chosen. This universal methodology simplifies the connection process by providing a consistent framework that handles the complexity of multiple potential targets.
Data Source
AI summary
Apparatus and methods to support emergency services sessions by network elements and by a wireless device are disclosed. The wireless device, when roaming to a visited country/region, queries a network-based server to obtain information for Public Land Mobile Networks (PLMNs) that support emergency services sessions via non-cellular wireless access in the visited country/region. The network-based server responds with a list of PLMNs from which the wireless device selects a PLMN. The wireless device further queries the network-based server to obtain information for evolved Packet Data Gateways (ePDGs) for a selected PLMN and receives from the network-based server a list of Internet Protocol (IP) addresses for ePDGs that support emergency services sessions via non-cellular wireless access for the selected PLMN. The wireless device further queries the network-based server for local numbers of the visited country for establishing emergency services sessions and receives a categorized list of local numbers for emergency services.