SMF P-CSCF List Transmission for Wireless Signal Activation

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Solution Overview

Problem

In wireless communication systems, when a P-CSCF failure occurs, existing methods lead to meaningless transmission of a new P-CSCF list to UE that cannot activate a PDU session via 3GPP access, resulting in the UE being unable to use IMS messages effectively.

Innovation Solution

A method where the SMF receives a reject message for a PDU session activation command, requests information on non-3GPP connection state modification from the AMF, and transmits a message with a new P-CSCF list to the UE only after the UE's non-3GPP connection state changes from CM-IDLE to CM-connected, ensuring efficient IMS message handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the AMF unconditionally transmits a session management message for a PDU session associated with a non-3GPP access to a UE, then the transmission of the P-CSCF list is performed, but the UE cannot activate the PDU session through 3GPP access resulting in meaningless transmission

Engineering Contradiction:

Improvetransmission efficiencyVSAvoiduseless P-CSCF list transmission

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The SMF performs preliminary checking of the UE's 3GPP access capability before transmitting the P-CSCF list. When the SMF receives a reject message indicating the UE cannot activate the PDU session through 3GPP access, it delays the transmission of the new P-CSCF list until the UE's non-3GPP connection state changes to CM-connected, thereby avoiding meaningless transmission.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The transmission of the P-CSCF list is made dynamic based on the UE's connection state. Instead of unconditional transmission, the SMF monitors the UE's non-3GPP connection state and only transmits the P-CSCF list when the UE transitions to CM-connected state, adapting the transmission timing to the actual network conditions.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the SMF delays transmission of the new P-CSCF list until UE is connected, then the UE can use IMS messages correctly, but the transmission time is increased

Engineering Contradiction:

ImproveIMS message utilizationVSAvoidtransmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The SMF uses feedback from the reject message and monitors the UE's connection state changes (CM-IDLE to CM-connected) to determine the optimal transmission timing. This feedback mechanism ensures the P-CSCF list is transmitted only when the UE is ready to receive and use it, improving reliability while minimizing unnecessary delays.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11153930B2Method for transmitting or receiving signal in wireless communication system and device for the same

Publication Date: 2021.10.19 LG ELECTRONICS INC

AI summary

A method for transmitting or receiving a signal of a Session Management Function (SMF) in a wireless communication system comprises receiving a reject message for a message related to an activation command of a Protocol Data Unit (PDU) session, by the SMF, from a User Equipment (UE); requesting, to an AMF, an Access Management Function (AMF) information on a non-3GPP connection state modification of the UE by the SMF; receiving a message indicating that a non-3GPP connection state of the UE has been changed, by the SMF, from the AMF; and transmitting the message related to the activation command of the PDU session, which includes a new P-CSCF(Proxy-Call Session Control Function) list, by the SMF, to the UE, wherein the message indicating that the non-3GPP connection state of the UE has been changed indicates that a non-3GPP access of the UE has been changed from CM-IDLE to CM-connected.