Serving Gateway VoIP Signal Conversion for LTE-2G/3G Handover
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Solution Overview
Problem
Conventional mobile communication systems face challenges in switching between LTE and 2G/3G radio access systems for voice communication, leading to increased handover delay and requiring SRVCC support in both home and visited networks, which complicates interworking and contract agreements.
Innovation Solution
A mobile communication system that switches between LTE and 2G/3G radio access systems by using a serving gateway device to convert VoIP media and control signals, allowing continuous voice communication within a visited network without requiring SRVCC support in the home network, thereby reducing switching time and simplifying network interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If path switching is performed between mobile stations in different networks, then voice communication continuity is maintained, but switching time increases and handover delay occurs
Solution Approach 1:
The gateway device pre-establishes conversion capabilities and maintains readiness to convert between circuit-switched signals and VoIP signals. By having the conversion function prepared in advance at the gateway device, the system can perform rapid switching without requiring complex real-time negotiations between home and visited networks, thus maintaining voice communication continuity while reducing switching time.
2Reliability
If SRVCC support is implemented in both home and visited networks, then seamless handover is achieved, but device complexity and interworking requirements increase
Solution Approach 1:
The gateway device acts as an intermediary between the circuit-switched network and the packet-switched network. It performs signal conversion and maintains communication continuity without requiring the mobile station or the home network to support SRVCC. This intermediary approach simplifies the overall system by concentrating the complexity in a single gateway device rather than requiring complex interworking between multiple network elements.
3Reliability
If SRVCC support is required in home network, then voice call continuity during roaming is ensured, but ease of operation and contract agreements become more difficult
Solution Approach 1:
The invention extracts the SRVCC functionality from the mobile station and home network, relocating it to the gateway device in the visited network. This extraction allows the mobile station to operate without SRVCC support while the gateway device handles the conversion and continuity functions locally, eliminating the need for complex home network configurations and international contract agreements.
Data Source
AI summary
In a mobile communication system capable of switching between a first communication state and a second communication state, in a case of a first communication state, a VoIP media signal is exchanged between a mobile station UE #1 and a mobile station UE #2 via an LTE radio access system and a node S-GW, a VoIP control signal is exchanged via the LTE radio access system, the node S-GW, and IMS, and in a case of a second communication state, a circuit-switched signal is exchanged between the mobile station UE #1 and an enhanced MSC/MGW via a 2G/3G radio access system, the VoIP media signal is exchanged between the enhanced MSC/MGW and the mobile station UE #2 via the node S-GW, and the VoIP control signal is exchanged between the enhanced MSC/MGW and the mobile station UE #2 via the node S-GW and the IMS.