MME CSFB Offloading for VoLTE Congestion
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Solution Overview
Problem
The growth of VoLTE subscriber bases leads to increased cell congestion in LTE networks, resulting in call drops and blocked calls due to higher bandwidth requirements and quality-of-service demands that existing technologies struggle to meet.
Innovation Solution
A service control method executed by a Mobility Management Entity (MME) that performs unsolicited circuit-switched fallback (CSFB) offloading, sending notification messages to user equipment to register in a CS domain when VoIMS is unavailable, indicating VoIMS unavailability through registration accept messages, thereby preventing voice call failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VoLTE is deployed to provide high-bandwidth voice services, then service quality and bandwidth capacity are improved, but cell congestion increases and call reliability deteriorates
Solution Approach 1:
The MME dynamically determines whether to indicate VoIMS unavailability to UEs based on real-time network congestion status. The system transitions between different operational states (VoLTE available vs. CSFB required) depending on current load conditions, allowing the network to adaptively manage capacity while maintaining call reliability.
Solution Approach 2:
The patent changes the parameter of service availability indication by setting the VoIMS availability status in registration accept messages based on network congestion levels. When congestion is detected, the MME changes the parameter value to indicate VoIMS unavailability, triggering CSFB behavior in UEs and thereby managing cell capacity while preserving voice call reliability.
2Reliability
If LTE resources are allocated to guarantee VoLTE bandwidth, then voice service quality is improved, but coverage area shrinks and cell congestion increases
Solution Approach 1:
The MME acts as an intermediary between the LTE packet-switched domain and the CS circuit-switched domain. It receives registration requests from UEs, determines VoIMS availability based on network conditions, and sends registration accept messages with appropriate VoIMS availability indications. This intermediary function allows seamless fallback to CS domain when LTE resources are insufficient, maintaining voice service quality across different network conditions.
3Reliability
If the MME indicates VoIMS unavailability to user equipment, then call failure is prevented and service reliability is improved, but network signaling overhead increases
Solution Approach 1:
The MME performs preliminary determination of VoIMS availability status before UE voice call attempts. By proactively indicating VoIMS unavailability in registration accept messages during normal network operations, the system prevents call failures before they occur, reducing the need for retry signaling and error correction messages that would otherwise increase overall signaling overhead.
Data Source
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AI summary
Embodiments of the present invention provide a service control method, a mobility management entity, and a mobile switching center, and the method includes: determining one or more user equipments; in a scenario of unsolicited circuit switched fallback CSFB offloading, sending a notification message to the one or more user equipments, and when a registration request message or a combined registration request message is received, sending a registration accept message or a combined registration accept message to the one or more user equipments; or in a scenario of solicited circuit switched fallback CSFB offloading, when a registration request message or a combined registration request message sent by the one or more user equipments is received, sending a registration accept message or a combined registration accept message to the one or more user equipments, so that a user equipment can communicate via a CS domain rather than suffering a voice call failure.