CSFB Indicator Management for Signaling Overload
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Solution Overview
Problem
Current systems providing circuit switched fallback (CSFB) service in cellular wireless networks are not configured to detect and address error conditions such as signaling overload or interface failures, leading to call setup delays and failures, with LTE base stations continuing to advertise CSFB availability even when it is not functioning properly.
Innovation Solution
The system monitors for error conditions associated with CSFB service, such as excessive signaling or interface failures, and directs UEs to refrain from using the service by ceasing to broadcast support indicators or sending specific instructions to affected UEs, allowing for remedial measures to prevent service interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If LTE base stations continuously broadcast CSFB service availability indicators, then UEs can quickly access CSFB service when needed, but error conditions like signaling overload and interface failures go undetected causing call setup delays and failures
Solution Approach 1:
The patent implements a feedback mechanism where the network side (MME or base station) monitors the status of CSFB service and provides feedback by adjusting broadcast indicators. When error conditions are detected (signaling overload, interface failures), the network stops broadcasting CSFB availability, preventing UEs from attempting failed service access. This resolves the contradiction by maintaining ease of operation during normal conditions while ensuring reliability during error conditions through dynamic indicator adjustment.
Solution Approach 2:
The patent makes the CSFB service availability indicator dynamic rather than static. The base station or MME dynamically adjusts whether to broadcast the CSFB indicator based on real-time service status. When service is functioning properly, the indicator is broadcast for quick UE access; when error conditions occur, broadcasting is suspended. This dynamic approach simultaneously achieves easy UE access during normal operation and reliable service indication during error conditions.
2Reliability
If the system monitors for error conditions and directs UEs to refrain from using CSFB service, then service reliability improves during error conditions, but additional signaling overhead is introduced to manage UE behavior
Solution Approach 1:
The patent extracts the error condition monitoring and service availability indication function from continuous operation to event-driven operation. Instead of continuously signaling UE to refrain from CSFB service (which would generate excessive signaling traffic), the system only adjusts broadcast indicators when error conditions are detected. This extraction approach maintains high reliability during errors while minimizing additional signaling overhead by acting only when necessary.
Solution Approach 2:
The patent implements a self-service mechanism where the network automatically detects error conditions and adjusts CSFB indicator broadcasting without requiring separate signaling to each UE. The MME or base station monitors service status and autonomously decides whether to broadcast availability indicators. This self-service approach improves reliability during error conditions while avoiding the signaling overhead that would result from individually notifying each UE.
Data Source
AI summary
In accordance with the disclosed methods and systems, while providing a service that enables user equipment devices (UEs) being served by a first network to engage in signaling with a second network via the first network, a controller or other network entity may detect an error condition associated with the service, such as a threshold-high level of signaling or an interface failure. In response to detecting the error condition, base stations in the first network may then direct one or more UEs being served by the first network to refrain from using the given service. As a result, the one or more UEs may refrain from using the given service and may instead use another approach to engage in signaling with the second network, which may enable the one or more UEs to circumvent the error condition until it gets remedied.