Emergency Call Handoff via Identified PGW
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Solution Overview
Problem
Emergency calls may be dropped or processed excessively slowly during handoffs between LTE and non-LTE networks, as existing systems fail to distinguish between initiated and handed-off emergency calls, leading to inappropriate routing and increased processing times.
Innovation Solution
The system identifies the packet data network gateway (PGW) associated with the emergency call prior to handoff and routes the call through this identified PGW, rather than another PGW, ensuring continuity and reducing processing time by distinguishing between initiated and handed-off emergency calls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If emergency calls are handled using standard handoff procedures between LTE and non-LTE networks, then network compatibility is maintained, but call connectivity is lost and processing time increases
Solution Approach 1:
The patent applies preliminary action by identifying and storing the original PGW associated with the emergency call before the handoff occurs. When handoff is detected, the system retrieves the stored PGW identifier and uses it to maintain the call routing, avoiding the time-consuming process of establishing a new emergency call connection after handoff.
Solution Approach 2:
The patent introduces an intermediary mechanism where the network device acts as a mediator between the user equipment and the PGW during handoff. The network device detects the handoff, identifies the original PGW, and facilitates the continuation of the emergency call through the same PGW, preventing call drops and reducing processing time.
2Adaptability or versatility
If emergency calls are routed through a different PGW after handoff, then network routing flexibility is improved, but call continuity is lost and service reliability deteriorates
Solution Approach 1:
The patent applies local quality by treating emergency call handoff differently from regular call handoff. While regular calls can be routed through any available PGW, emergency calls are specifically routed through the original identified PGW to maintain continuity. This localized differentiation ensures emergency call reliability without compromising overall network routing flexibility.
3Measurement precision
If the system distinguishes between initiated and handed-off emergency calls, then call processing accuracy is improved, but system complexity increases
Solution Approach 1:
The patent uses preliminary action by pre-identifying and storing the PGW associated with emergency calls before handoff occurs. This preliminary identification creates a reference that simplifies the handoff detection process, as the system only needs to compare the current routing with the stored identifier rather than performing complex analysis during the handoff event.
Solution Approach 2:
The network device performs self-service by automatically detecting handoff events and identifying the original PGW without requiring external intervention or complex coordination with other network elements. The device uses its own stored context information to maintain emergency call routing, reducing overall system complexity.
Data Source
AI summary
A system to receive, from a user device, a request to establish a communication session to allow an emergency call to be placed or transferred to a public safety access point (PSAP) server; determine whether the request includes a first indication that the emergency call is being initiated via the user device or a second indication that the emergency call is being handed off from a base station associated with another network device, place the emergency call, to the PSAP server and via a first gateway device associated with the network device, when the request includes the first indication; and transfer the emergency call, to the PSAP server and via a second gateway device associated with the other network device, when the request includes the second indication, where the second gateway device processed the emergency call prior to being handed off from the base station.