eMSC–IMS Registration State Synchronization for Reliable Calls

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Inconsistent registration states between a terminal in the Mobile Switch Center enhanced for ICS (eMSC) and the IP Multimedia Subsystem (IMS) lead to failed call services due to redundant signaling and resource consumption, as the eMSC lacks subscription to registration state information, causing the eMSC to incorrectly forward calls when states are inconsistent.

Innovation Solution

A method and apparatus that decide on the consistency of terminal states between eMSC and IMS, sending registration requests to synchronize states without subscribing to IMS registration information, allowing terminals to complete initial call services efficiently by re-registering if necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the eMSC subscribes to registration state information in the IMS, then the registration state consistency between eMSC and IMS can be maintained, but the network signaling traffic and processing overhead increase

Engineering Contradiction:

Improveregistration state consistencyVSAvoidnetwork signaling traffic

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the registration state synchronization function from the subscription-based mechanism and implements it through event-triggered registration requests. Instead of continuous subscription, the eMSC only initiates registration requests when it detects state inconsistency, thereby removing the harmful continuous signaling overhead while maintaining the essential synchronization function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The terminal performs self-registration with the IMS network when the eMSC detects state inconsistency. The eMSC sends a registration request to trigger the terminal to re-register, allowing the system to self-correct state inconsistencies without requiring continuous external monitoring or subscription-based state push mechanisms.

Inventive Principle:

Principle #25Self-service

2Reliability

If the eMSC continuously monitors registration state information, then the state consistency can be ensured, but the CPU consumption and processing efficiency decrease

Engineering Contradiction:

Improvestate consistencyVSAvoidprocessing efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of continuous monitoring, the system adopts periodic action triggered by specific events. The eMSC checks registration state consistency at key moments (when terminal state changes are detected) rather than continuously, converting a high-overhead continuous process into efficient event-driven periodic actions that maintain reliability while improving processing efficiency.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system implements feedback mechanisms where the eMSC monitors terminal states and receives responses from IMS registration attempts. When inconsistency is detected through feedback, the eMSC triggers corrective registration requests, creating an efficient closed-loop control system that maintains state consistency without continuous monitoring overhead.

Inventive Principle:

Principle #23Feedback

3Quantity of substance

If the eMSC does not subscribe to registration state information, then the network resource consumption is reduced, but the call service reliability deteriorates due to state inconsistency

Engineering Contradiction:

Improvenetwork resource consumptionVSAvoidcall service reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The system performs preliminary registration requests proactively when the eMSC detects potential state inconsistency, before actual call service failures occur. By initiating registration synchronization in advance based on terminal state changes, the system prevents reliability issues while avoiding continuous monitoring, thus resolving the contradiction between resource consumption and service reliability.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If redundant registration requests are sent to synchronize states, then the state consistency is improved, but the network signaling overhead increases

Engineering Contradiction:

Improvestate synchronizationVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by making registration requests targeted and context-specific rather than universal. The eMSC analyzes local terminal state information and sends registration requests only when specific inconsistency conditions are met, rather than sending requests to all terminals uniformly. This localized approach maintains synchronization reliability while minimizing unnecessary signaling overhead.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP4117248B1Method and apparatus for implementing call service, electronic device and readable medium

Publication Date: 2025.10.22 ZTE CORP

Figure 1~2
Figure 3~5
Figure 6

AI summary

A call service implementation method and apparatus, and an electronic device and a readable medium. The method comprises: determining whether a first state of a terminal in an eMSC is consistent with a second state of the terminal in an IMS; if the first state of the terminal in the eMSC is inconsistent with the second state of the terminal in the IMS, sending a registration request to the IMS, so that the terminal completes an initial call service, wherein the eMSC does not subscribe to registration state information in the IMS.