Voice Call Continuity in Hybrid Networks via VoIP Anchoring
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Solution Overview
Problem
Existing voice call continuity solutions in hybrid network infrastructures face challenges in maintaining seamless call connections across different wireless networks, often resulting in interruptions due to unpredictable latency and the need for user intervention, especially when switching between Wi-Fi and cellular networks.
Innovation Solution
The implementation of a voice call continuity system that anchors media and signaling in a core VoIP network, using a unique VCC identifier to manage call handovers between different network types, ensuring continuous and uninterrupted calls by selecting the lowest cost, highest quality connection, and maintaining call context through media relays and conference bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If voice calls are switched between Wi-Fi and cellular networks manually or without anchoring, then network cost is reduced, but call continuity is interrupted and user experience deteriorates
Solution Approach 1:
The patent introduces a conferencing gateway as an intermediary entity that anchors the call. When switching between Wi-Fi and cellular networks, the call is routed through this gateway which maintains the call context and enables seamless handover. The gateway acts as a mediator that preserves call continuity while allowing network switching, resolving the contradiction between cost reduction and reliability maintenance.
Solution Approach 2:
The system performs preliminary actions by establishing a connection to the conferencing gateway before network switching occurs. The gateway pre-allocates resources and prepares the call context in advance, so when network switching is needed, the handover can occur smoothly without interruption. This preliminary preparation ensures call continuity is maintained while enabling cost-effective network switching.
2Device complexity
If call handover is implemented without parallel media paths, then system complexity is reduced, but call interruption occurs during switching
Solution Approach 1:
The patent implements continuity of useful action by establishing parallel media paths during handover. The original call leg is maintained while a new call leg is being set up, ensuring that voice transmission continues uninterrupted. Both media paths operate simultaneously during the transition, and the system seamlessly switches between them, maintaining continuous useful action throughout the handover process without perceptible interruption to the user.
Data Source
AI summary
Voice call continuity is provided for calls that are carried over a hybrid network infrastructure in which access connections are distributed over loosely coupled network portions including a backend network such as a core VoIP (Voice over Internet Protocol) service network, one or more cellular mobile networks, and a public switched telephone network ("PSTN"). The calls are routed through the core VoIP network regardless of their points of origination or termination in other network portions so that signaling and call context are anchored in the core VoIP network. The conditions under which user equipment operate are continuously monitored so that when a connection is determined to have been unacceptably degraded or is likely to be interrupted, and/or a more optimal connection is available, a handover of the call to another connection is initiated so that call continuity is maintained using the lowest cost connection that provides acceptable call quality.