Regional S-CSCF Selection for Lower IMS Registration Latency
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Solution Overview
Problem
Existing telecommunication networks face increased network latency and degraded customer experience due to UE registrations across different regions, causing more IP hops and longer call setup times when users handover or reconnect to different network regions.
Innovation Solution
Implement location-based S-CSCF selection in IMS networks by determining the current region of a user equipment (UE) and selecting a suitable S-CSCF within that region for re-registration, rather than assigning a previously used S-CSCF from a different region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE is registered on an S-CSCF from a different region, then the network can handle user mobility and reconnection, but network latency increases and call setup time lengthens
Solution Approach 1:
The patent applies local quality by selecting S-CSCF servers based on the UE's current geographic region. The I-CSCF queries the UE's location information and selects an S-CSCF from the same region, ensuring that network elements are geographically localized. This reduces the need for long-distance signaling and IP hops, thereby decreasing network latency while maintaining adaptability to user mobility.
Solution Approach 2:
The patent segments the network into multiple geographic regions, each with its own S-CSCF servers. By dividing the network infrastructure into region-specific segments, the system can handle user mobility within regions efficiently while minimizing cross-region signaling. This segmentation allows the network to adapt to user movement without incurring the latency penalty of inter-region communication.
2Reliability
If UE handovers between different network regions, then the network supports seamless connectivity, but call setup time increases due to additional IP hops
Solution Approach 1:
The patent ensures that during UE handover between network regions, the S-CSCF selection is based on the current region's location information. This local quality approach maintains seamless connectivity within each region by keeping signaling local, while the region-based segmentation allows smooth transitions during handover without requiring long-distance IP hops, thus reducing call setup time.
3Speed
If the network is divided into multiple independent regions, then network latency is improved and outages are limited, but S-CSCF selection becomes more complex
Solution Approach 1:
The patent introduces the I-CSCF as an intermediary that manages the complexity of S-CSCF selection across multiple regions. The I-CSCF queries the UE's location information and automatically selects the appropriate S-CSCF from the correct region, shielding the rest of the system from the complexity of multi-region management. This intermediary approach maintains low network latency by ensuring local S-CSCF selection while centralizing the selection logic to manage complexity.
4Device complexity
If S-CSCF selection is based on previous registration, then device complexity is reduced, but network performance degrades due to cross-region interactions
Solution Approach 1:
The patent improves network performance by selecting S-CSCF servers based on the UE's current region rather than previous registration location. This local quality approach ensures that signaling and service delivery occur within the same geographic region, reducing IP hops and improving network performance. The I-CSCF queries current location information and selects the appropriate regional S-CSCF, maintaining simple selection logic while optimizing network performance.
Data Source
AI summary
Methods and systems for a location-based serving call session control function (S-CSCF) selection in an IP multimedia subsystem (IMS) network is disclosed. According to an implementation, an interrogating CSCF (I-CSCF) of an IMS network receives a request to register a user equipment (UE) to use an IP multimedia service. The request may be a session initiation protocol (SIP) register. The I-CSCF determines that the UE is located in a first region based on the geographic information in the request. The I-CSCF may determine, based at least in part on the cell global identity (CGI) information in the SIP register, that the UE is previously registered through a different region. The I-CSCF may determine a serving CSCF (S-CSCF) located in the first region to provide the IP multimedia service to the UE. The I-CSCF further registers the UE on the S-CSCF.