Service Continuity Supporting Entity for LTE to GSM Handover
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
User Equipment (UE) cannot simultaneously access both LTE and GSM/WCDMA networks, making seamless call handover between packet switched and circuit switched networks challenging.
Innovation Solution
A Service Continuity Supporting Entity (SCSE) is introduced to translate handover request messages between GPRS Tunneling Protocol (GTP) and Mobile Application Part (MAP) messages, enabling seamless handover by setting up bearers and assigning circuit switched call routing numbers for UE in the circuit switched network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE attempts to handover between LTE and GSM/WCDMA networks, then call continuity is improved, but network access conflict occurs because UE cannot simultaneously access both networks
Solution Approach 1:
The patent introduces a Session Anchor (SA) as an intermediary entity that anchors the voice call session. The SA receives handover requests from the LTE network, translates them to the GSM/WCDMA network, and coordinates the handover process. This intermediary enables call continuity by mediating between the two networks that the UE cannot simultaneously access, allowing the UE to switch networks without dropping the call.
2Ease of operation
If traditional handover methods are used assuming simultaneous network access, then handover procedure is simplified, but handover fails when UE cannot access both networks simultaneously
Solution Approach 1:
The patent performs preliminary actions by establishing the Session Anchor before handover and pre-coordinating the handover preparation with the target network. The SA is set up in advance to anchor the call, and handover requests are prepared and validated before actual network switching occurs. This preliminary preparation ensures handover success even when the UE cannot simultaneously maintain connections to both networks.
Data Source
AI summary
A method and apparatus for performing handover on a voice call between a packet network system and a circuit network system is provided. Considering a communication environment where a UE cannot simultaneously use radio resources of both the next generation mobile communication system (LTE) and the legacy mobile communication system (e.g., GSM/WCDMA), the present invention proposes an SCSE for performing signal translation between the packet switched network and the circuit switched network and anchoring a voice call in the application level, and supports a continuous voice call using the SCSE.