VoLTE Call Setup Delay During LTE Handoff
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Solution Overview
Problem
In LTE mobile networks, the establishment of a dedicated bearer channel for VoLTE calls often fails when a mobile device transitions between wireless network nodes, leading to insufficient quality of service and impacted call quality due to the default bearer channel's inability to handle higher QoS requirements.
Innovation Solution
The system delays the establishment of a dedicated bearer channel until the mobile device has completed its transition between network nodes by querying the serving gateway for transition status and only proceeds with the request once the device is associated with the new node, ensuring a stable connection for VoLTE calls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the dedicated bearer channel establishment request is processed immediately, then the call setup speed is improved, but the bearer channel establishment fails when the device is transitioning between network nodes
Solution Approach 1:
The system performs preliminary detection of the device's transition status before processing the bearer channel establishment request. The serving gateway checks whether the device is currently transitioning between network nodes, and only if the device is in a stable state does it proceed with the bearer channel establishment. This preliminary action prevents establishment failures while maintaining efficient call setup.
2Duration of action of stationary object
If the dedicated bearer channel is established during device transition, then the service continuity is maintained, but the quality of service deteriorates due to connection instability
Solution Approach 1:
The system implements feedback mechanisms where the serving gateway continuously monitors the device's connection status and transition state. Based on this feedback, the gateway dynamically decides whether to proceed with bearer channel establishment or delay it until the device stabilizes. This feedback-driven approach ensures service continuity while maintaining high quality of service by avoiding establishment during unstable transition periods.
Data Source
AI summary
A network gateway receives a voice over long term evolution (VoLTE) call establishment request from an internet protocol (IP) multimedia services (IMS) core network for a mobile device. The network gateway queries a serving gateway to determine whether the mobile device is transitioning from a first evolved node B (eNB) to a second eNB. If the mobile device is transitioning, based on the existence of a user plane modify request, the network gateway delays forwarding the received request to a mobility management entity until the serving gateway informs the network gateway that the serving gateway received a first data packet from the mobile device via the second eNB as an indication the transition is complete.