Emergency Call Service via NAS Protocol in Mobile Networks
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Solution Overview
Problem
The existing mobile communication systems, particularly 3GPP-EPS, face challenges in efficiently supporting emergency call services due to undefined procedures for unauthenticated terminals and delayed service launch, especially when transitioning between different radio access technologies.
Innovation Solution
A method and system that utilize NAS protocol message exchanges between User Equipment (UE) and Mobility Management Entity (MME) to facilitate emergency call services, including transmitting an attach request with an emergency call indicator, requesting authentication, and providing emergency call services upon receiving an attach accept message, enabling efficient emergency call handling even in unauthenticated states and during handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If authentication procedures are performed before emergency call service, then service reliability is improved, but service accessibility deteriorates for unauthenticated terminals
Solution Approach 1:
The attach procedure is segmented into two independent paths: one for authenticated terminals and one for unauthenticated terminals. The unauthenticated path includes emergency call indicator setting and MME authentication attempt, while the authenticated path proceeds directly to bearer setup. This segmentation allows unauthenticated terminals to access emergency services without being blocked by standard authentication requirements.
Solution Approach 2:
The emergency call indicator is set in advance in the attach request message before the authentication decision is made. This preliminary action ensures that the MME is alerted to the emergency nature of the call before authentication procedures complete, enabling immediate service provision for unauthenticated terminals while maintaining security through subsequent authentication attempts.
2Reliability
If authentication and location update procedures are performed, then service security is improved, but service launch time deteriorates
Solution Approach 1:
The emergency call indicator is included in the attach request message before authentication and location update procedures complete. This preliminary indication allows the MME to prioritize the request and initiate authentication and location update procedures in parallel, significantly reducing service launch time while maintaining security through complete authentication.
Solution Approach 2:
Authentication and location update procedures are performed continuously and in parallel rather than sequentially. The MME initiates authentication upon receiving the attach request with emergency indicator, and location update procedures proceed simultaneously, eliminating idle waiting time and accelerating service launch while ensuring both security and location accuracy.
3Adaptability or versatility
If CSFB or handover to 3GPP2 is performed for voice call service, then service compatibility is improved, but system complexity deteriorates
Solution Approach 1:
The EPS network is enhanced with multi-functionality to directly support emergency voice calls using packet switched technology, eliminating the need for separate CSFB or 3GPP2 handover mechanisms. The same EPS infrastructure handles both normal packet services and emergency voice calls, reducing system complexity while maintaining compatibility across different scenarios.
Solution Approach 2:
The complex CSFB and 3GPP2 handover procedures are extracted and replaced by a simplified emergency attach procedure within EPS. The emergency call indicator mechanism allows the system to take out the need for inter-system handovers by handling emergency calls natively within the packet switched domain, reducing overall system complexity.
Data Source
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AI summary
The present invention relates to a method and a system for managing an emergency call between a terminal and a network by using a non-access stratum protocol in a mobile communication network. A method for providing an emergency call service by a terminal in accordance with one embodiment of the present invention comprises the steps of: enabling the terminal to transmit an access request message including an emergency call identifier to a mobility management entity; enabling the terminal to attempt to authenticate the mobility management entity after the step of transmitting the access request message; enabling the terminal to receive an access grant message including the emergency call identifier from the mobility management entity; and enabling the terminal which receives the access grant message, to provide an emergency call service through the mobility management entity. According to one embodiment of the present invention, the emergency call is enabled.