Transit Network VoLTE Roaming Signaling Routing
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Solution Overview
Problem
Current wireless communication systems face challenges in handling Roaming II-NNI within transit networks, which are not capable of supporting VoLTE roaming without deploying additional IMS/VoLTE service elements, leading to significant investment and impeded VoLTE roaming services.
Innovation Solution
Deploying IMS/VoLTE service elements at the transit network to enable efficient routing of session control messages and registration requests, using domain-based routing for roaming signaling and called party number routing for non-roaming signaling, and modifying SIP INVITE messages to include TRF information for seamless call delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IMS/VoLTE service elements are deployed at the visited LTE network to enable VoLTE roaming service, then VoLTE roaming service capability is improved, but network investment cost increases significantly
Solution Approach 1:
The patent introduces a transit network as an intermediary between the home LTE network and visited LTE network. The transit network hosts IMS/VoLTE service elements (P-CSCF, IBCF, TRF) that act as mediators to handle roaming signaling and call control, allowing the visited network to provide VoLTE roaming services without deploying its own service elements, thus reducing network investment while maintaining service capability
Solution Approach 2:
The transit network is designed with multi-functional capability to serve multiple purposes: it acts as a routing intermediary for roaming traffic, hosts shared IMS/VoLTE service elements that can serve multiple visited networks, and provides call control functions. This universal approach allows one transit network to support VoLTE roaming for multiple operators, distributing the investment cost across multiple networks
2Adaptability or versatility
If IMS/VoLTE service elements are deployed at the visited LTE network, then call routing capability is improved, but device complexity increases
Solution Approach 1:
The transit network with its hosted service elements (P-CSCF, IBCF, TRF) serves as an intermediary that centralizes the complexity of call routing and signaling handling. Instead of each visited network deploying complex service elements, the transit network absorbs this complexity and provides simplified interfaces to visited networks, reducing device complexity at the visited network while maintaining advanced call routing capability
Solution Approach 2:
The patent implements feedback mechanisms where the transit network collects routing information from registration requests and call signaling, learns optimal routing paths, and uses this learned information to improve future routing decisions. The TRF element maintains routing information databases that are continuously updated based on network conditions and call patterns, enabling intelligent adaptive routing without increasing structural complexity
3Measurement precision
If domain-based routing is used for roaming signaling, then routing accuracy is improved, but signaling processing complexity increases
Solution Approach 1:
The TRF element at the transit network implements feedback-based routing where routing decisions are made based on learned routing information from previous calls and registration data. The system continuously updates routing databases with successful call patterns and network conditions, using this feedback to improve routing accuracy over time while automating the processing complexity through intelligent algorithms rather than manual configuration
Data Source
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AI summary
According to at least one example embodiment, a transit network is configured to handle signaling messages between service provider networks. Upon receiving, at the transit network, a session control message from a mobile network, a signaling type associated with the session control message is determined. The transit network then routes the session control message based on the signaling type determined. According to at least one aspect, the session control message is routed based on domain routing if the determined signaling type is roaming signaling. According to at least one other aspect, the session control message is routed based on called party number routing if the determined signaling type is non-roaming signaling.