UE Emergency Fallback via NAS Failure Detection
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Solution Overview
Problem
Current 3GPP specifications do not fully specify UE behavior for failed registration and service requests during emergency services fallback in mobile communications, particularly when network registration requests are rejected or fail due to message transmission failures.
Innovation Solution
The proposed solution involves a UE determining failure in initiating mobility registration or service requests for emergency services fallback, with the UE NAS layer in the 5GMM protocol informing upper layers of the failure, triggering actions such as de-registration, initial registration for emergency services, and attempting emergency calls in different domains or networks like CS or IP-CAN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE follows current 3GPP specifications for emergency services fallback, then the basic registration and service request procedures are supported, but the UE behavior is not fully specified when registration requests are rejected or fail due to message transmission failures
Solution Approach 1:
The patent applies preliminary action by defining UE behavior in advance for failure scenarios. The specification pre-establishes what the UE should do when registration requests are rejected or fail, including initiating service requests and attempting emergency calls in different domains, rather than leaving the behavior undefined until the failure occurs
Solution Approach 2:
The patent implements feedback mechanisms where the UE monitors registration request outcomes and adjusts its behavior accordingly. When registration fails, the UE receives feedback about the failure condition and responds by initiating service requests or attempting emergency calls in alternative domains, creating a closed-loop failure handling mechanism
2Adaptability or versatility
If the UE attempts multiple alternative network connections for emergency services, then the service availability is improved, but the time and signaling overhead increases
Solution Approach 1:
The patent applies dynamics by making the UE's network selection behavior adaptive rather than static. The UE dynamically chooses its fallback actions based on the specific failure condition detected, selecting from multiple possible paths (service request initiation, emergency call in different domain, or other alternatives) depending on the situation
Solution Approach 2:
The patent utilizes parameter changes by modifying the UE's operational parameters based on failure conditions. When registration fails, the UE changes its behavior parameters to attempt service requests or emergency calls in different domains, adjusting its operational mode to match the failure scenario
Data Source
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AI summary
Solutions pertaining to user equipment, UE, behavior for failed registration request or service request for emergency services fallback in mobile communications are proposed. An apparatus implemented in a UE determines a failure in attempting to initiate a mobility registration request procedure or a service request procedure with a network to perform an emergency service fallback (310). In response to the determining, the apparatus performs one or more operations including at least a UE non-access-stratum, NAS, layer in a 5th Generation Mobility Management, 5GMM, protocol informing an upper layer in the 5GMM protocol of the failure to cause the upper layer to attempt an emergency call in a different domain or via a different network (320).