Residential Gateway SIP Proxy for Seamless VoIP Cellular Handover
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Solution Overview
Problem
There is currently no solution that enables seamless call mobility between wireless VoIP networks and cellular networks without upgrading the network infrastructure of either the VoIP provider or cellular networks, limiting the ability of dual-mode phones to move calls between these networks.
Innovation Solution
A residential gateway apparatus that performs Session Initiation Protocol (SIP) functions, including acting as a proxy server and registrar, allows dual-mode phones to move calls between VoIP and cellular networks by using pre-configured DTMF signal digit sequences to initiate handover processes, such as 'hand-out' and 'hand-in' scenarios, without requiring changes to the VoIP service provider or SIP infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dual-mode phones are used to enable call mobility between VoIP and cellular networks, then call mobility capability is improved, but infrastructure upgrade requirements increase network complexity and cost
Solution Approach 1:
The residential gateway acts as an intermediary device that mediates between the VoIP network and cellular network. It implements SIP proxy and registrar functions to enable dual-mode phones to move calls between networks without requiring infrastructure upgrades at the service provider level. The gateway translates and manages signaling between different network protocols and architectures.
Solution Approach 2:
The solution segments the call mobility functionality into the residential gateway device, separating it from the core network infrastructure. This allows the complex handover logic and protocol translation to be implemented at the customer premises equipment rather than requiring changes to the service provider's network infrastructure.
2Ease of manufacture
If seamless call mobility is implemented without infrastructure upgrades, then ease of deployment is improved, but call handover reliability may deteriorate
Solution Approach 1:
The residential gateway pre-establishes registration and signaling relationships with both VoIP and cellular networks before handover is needed. It maintains SIP registration state and network connectivity in advance, enabling rapid and reliable call transfer when dual-mode phones need to move between networks without service interruption.
Solution Approach 2:
The system implements feedback mechanisms where the residential gateway continuously monitors the status of dual-mode phones and network conditions. It uses SIP signaling to track device location and maintain call state, enabling reliable handover decisions based on real-time network status and device availability.
Data Source
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AI summary
A system and method for providing call mobility for a dual-mode phone (180) between a cellular network and a home wireless network for a dual-mode phone (180) having a cellular identity and a home identity, wherein the home identity is active when the dual-mode phone (180) is in communication with the home wireless network. The system comprises a residential gateway (160) to connect the home wireless network to a public network, and a VoIP service provider (140) in communication with a mobile switching center (130) on the cellular network and the public network. After placing or receiving a call, the dual-mode phone (180) sends a signal to the residential gateway (160) to initiate the movement of the call between the cellular network and the home wireless network while the call is ongoing.