VoWiFi Handover Provisioning via VoLTE Backup
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Solution Overview
Problem
VoWiFi to VoWiFi handovers in LTE networks are prone to failure due to the short range of Wi-Fi access points and device movement, leading to disconnected calls and increased delay in reconnection, which negatively impacts user experience.
Innovation Solution
Implementing a method that detects requests to join a new Wi-Fi access point and, if the connection fails, initiates a provisional link to the cellular network to ensure continuous voice service, thereby minimizing service disruptions and maintaining call connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If VoWiFi handover is used to maintain connectivity during device movement, then service coverage is extended, but handover reliability deteriorates due to short Wi-Fi access point range and device movement
Solution Approach 1:
The system performs preliminary actions by detecting handover requests before the actual handover occurs and initiating provisional link establishment to the cellular network in advance. This allows the device to prepare a backup connection path before the Wi-Fi handover fails, thereby maintaining service continuity and improving handover reliability while preserving extended coverage through VoWiFi.
2Loss of energy
If VoWiFi is used for voice service, then cellular network load is reduced, but service continuity deteriorates due to handover failures
Solution Approach 1:
The system performs preliminary actions by detecting handover requests before the actual handover occurs and initiating provisional link establishment to the cellular network in advance. This allows the device to prepare a backup connection path before the Wi-Fi handover fails, thereby maintaining service continuity and improving handover reliability while preserving extended coverage through VoWiFi.
Solution Approach 2:
The system sets up emergency or compensatory measures in advance by establishing a provisional cellular link when a Wi-Fi handover is detected. This cushioning mechanism ensures that if the Wi-Fi handover fails, the cellular link is already prepared to take over, preventing service interruption and maintaining continuity without requiring full cellular network load.
3Reliability
If handover detection and provisional link establishment is implemented, then service reliability is improved, but device complexity increases
Solution Approach 1:
The system introduces an intermediary function in the form of a handover manager that coordinates between the Wi-Fi and cellular network interfaces. This intermediary component simplifies the overall device complexity by centralizing the handover detection and provisional link establishment logic, rather than requiring complex coordination between multiple network stacks and protocols.
Data Source
AI summary
A user entity (UE) such as a smartphone is configured to connect to both Wi-Fi and a Long Term Evolution (LTE) cellular network for voice and data services. For voice, the UE supports both Voice over LTE (VoLTE) and Voice over Wi-Fi (VoWiFi). When the UE is connected to VoWiFi and roaming from a first Wi-Fi access point to a second Wi-Fi access point, the UE and Mobility Management Entity in the cellular network carry out a preparatory handover to VoLTE to prevent service loss in the event of an unsuccessful VoWiFi connection from the second Wi-Fi access point.