IMS Capability Signaling for SIP Reliability During EPS Fallback
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Solution Overview
Problem
In wireless networks supporting interworking between 5G and EPS without an N26 reference point, the use of Transmission Control Protocol (TCP) for Session Initiation Protocol (SIP) signaling during multimedia telephony service establishment can lead to limitations due to network address translation, potentially causing loss of SIP signaling during EPS fallback.
Innovation Solution
The IMS network indicates its capability for EPS fallback by using a combination of the contact header field and an indicator in SIP messages, allowing the UE to establish data sessions without relying on TCP, thereby maintaining SIP signaling integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TCP is used as the transport protocol for SIP signaling during MMTEL session establishment in EPS fallback, then SIP signaling loss is avoided, but network latency increases and resource consumption increases
Solution Approach 1:
The patent changes the transport protocol parameter from TCP to UDP for SIP signaling during EPS fallback. The network indicates EPS fallback capability support, and the UE utilizes UDP-based transport to avoid TCP's connection establishment overhead and resource-intensive handshaking, thereby reducing latency while maintaining sufficient reliability through UDP's connectionless nature.
2Reliability
If TCP is used as the transport protocol for SIP signaling, then connection reliability is improved, but device complexity and resource consumption increase
Solution Approach 1:
The patent changes the transport protocol parameter from TCP to UDP, simplifying the protocol handling complexity. UDP requires no connection establishment, no acknowledgments, and no retransmission logic, thereby reducing device complexity and resource consumption while maintaining sufficient reliability for SIP signaling in EPS fallback scenarios.
3Reliability
If TCP is used for SIP signaling during EPS fallback, then signaling loss is prevented, but network resource consumption increases
Solution Approach 1:
The patent changes the transport protocol from TCP to UDP, reducing network resource consumption. UDP's connectionless nature eliminates the need for three-way handshakes, continuous acknowledgments, and flow control mechanisms, thereby saving bandwidth and processing resources while maintaining adequate signaling integrity for MMTEL session establishment during EPS fallback.
Data Source
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AI summary
Apparatuses, methods, and systems are disclosed for indicating the IMS capability for EPS fallback. One apparatus (500) in a mobile communication network includes a processor (505) and a transceiver (525) that transmits (705) to an IMS network entity a first SIP message comprising a request for establishing a data session, where the first SIP message contains a first contact header field. The transceiver (525) receives (710) a second SIP message (i.e., indicating successful registration) from the IMS network entity for establishing the data session, where the second SIP message contains an indicator. The processor (505) determines (715) an IMS network capability from a combination of the first contact header field and the indicator.