MME Tracking Area Update for Mobile Packet Call Reception
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Solution Overview
Problem
In the EPC network, when a UE moves out of its registered area, incoming packet calls are not successfully received due to the UE's inability to receive notifications during the Tracking Area Update process, as the new MME has not completed registration and the SGW sends notifications to the old MME, which cannot reach the UE.
Innovation Solution
The MME performs Tracking Area Update processing, receiving and responding to control signals from the PGW, and after completion, the PGW sends control signals to the new MME managing the UE's location, ensuring seamless communication during UE movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE moves out of its registered area and sends a location registration request message to a new MME, then the UE can be registered in the new MME that manages the location registration area, but when an incoming packet call arrives during the movement process, the UE cannot receive the call because the SGW sends the incoming call notification message to the old MME which cannot reach the UE
Solution Approach 1:
The new MME performs preliminary actions by proactively notifying the PGW that it is managing the UE's location registration area before the UE completes the movement process. This allows the PGW to prepare and redirect incoming call notification messages to the new MME in advance, ensuring the UE can receive calls during movement without waiting for the old MME to forward messages.
Solution Approach 2:
The new MME acts as an intermediary between the SGW and the UE during the movement process. Instead of relying on the old MME to forward incoming call notification messages, the new MME intercepts these messages from the SGW and redirects them to itself, serving as a mediator that ensures seamless message delivery during the transition period.
2Device complexity
If the SGW sends the incoming call notification message to the old MME that managed the UE's location before movement, then the message routing is simple, but the UE cannot receive the message because it has moved to the new MME's area
Solution Approach 1:
The new MME provides feedback to the PGW by sending a notification message indicating that it is now managing the UE's location registration area. This feedback mechanism allows the PGW to update its routing information and send future incoming call notification messages directly to the new MME, ensuring reliable message delivery while maintaining relatively simple routing logic.
3Reliability
If the UE completes location registration in the new MME before receiving the incoming packet call, then the UE can receive the call normally, but there is a timing issue where calls arriving during the movement process cannot be delivered
Solution Approach 1:
The new MME performs the preliminary action of notifying the PGW before the UE completes the location registration process. This proactive notification ensures that the PGW is already configured to send incoming call notification messages to the new MME, making the system adaptable to calls arriving at any stage of the movement process, not just after completion.
Data Source
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AI summary
An exemplary object is to provide a communication system, an MME and a communication method that perform control so as to reliably receive an incoming packet call that is made during movement of a UE. The communication system according to an exemplary embodiment of the invention includes an MME (25) that, by movement of a UE (45), performs Tracking Area Update processing that changes a location registration area of the UE (45) and manages the location registration area of the UE (45) before change, and a PGW (75) that sends, to the MME (25), a control signal required to be notified to the UE (45) during execution of the Tracking Area Update processing. When the MME (25) receives the control signal, it sends a response signal indicating that the Tracking Area Update processing is being executed to the PGW (75), and, after completion of the Tracking Area Update processing, the PGW (75) sends the control signal to an MME (35) that manages the location registration area of the UE (45) after change.