VoIP Handover Proxy for Seamless WLAN to WWAN Switching
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Solution Overview
Problem
Current technologies fail to seamlessly handover voice calls between wireless local area networks (WLAN) and wireless wide area networks (WWAN) due to the deconstruction of SIP, RTP, or RTCP sessions, leading to disruptions in voice-based applications.
Innovation Solution
The implementation of a VoIP handover proxy and proxy server module that enables infrastructure-less handover of applications between heterogeneous wireless networks, using SIP re-invite messages to maintain a continuous session across different wireless networks, ensuring a 'make before break' connection to prevent service interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If session handover between WLAN and WWAN is implemented using conventional technologies, then network switching capability is improved, but session continuity deteriorates due to deconstruction of SIP, RTP, or RTCP sessions
Solution Approach 1:
The patent introduces a SIP proxy server as an intermediary component that mediates between the UE and the network during handover. The SIP proxy server receives SIP re-invite messages from the UE, extracts connection information, and establishes new media sessions without requiring the UE to manually manage complex session transitions. This intermediary handles the complexity of session maintenance across network boundaries, allowing seamless handover while preserving session continuity.
Solution Approach 2:
The patent implements preliminary actions by establishing the new media session before breaking the old one. The SIP re-invite message is sent in advance to set up the new connection path, and only after the new session is successfully established does the system transition away from the old network connection. This 'make-before-break' approach ensures that session continuity is maintained throughout the handover process.
2Reliability
If infrastructure-less handover is implemented using SIP re-invite messages, then service continuity is improved, but device complexity increases due to manual session management requirements
Solution Approach 1:
The patent extracts the complex session management functionality from the UE and relocates it to the network infrastructure, specifically the SIP proxy server. The UE only needs to send simple SIP re-invite messages with updated connection information, while the sophisticated logic for maintaining session state, managing media paths, and coordinating handover is handled by the extracted session management components in the network. This extraction reduces device complexity while preserving service continuity.
3Ease of operation
If manual session management is required for handover, then connection control is improved, but handover time increases due to deconstruction and reconstruction of sessions
Solution Approach 1:
The patent ensures continuity of useful action by maintaining the SIP session context throughout the handover process. Instead of completely terminating and recreating sessions, the system continuously updates the session parameters through SIP re-invite messages. The media session remains active while the underlying transport path changes, allowing voice or data transmission to continue without interruption. This continuous action approach minimizes handover time while preserving connection control.
Data Source
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AI summary
An apparatus for the handover of a transmission of a data application. The apparatus includes a computer device, and the computer device includes a wireless receiver and a wireless transmitter. The data application is transmitted over a first wireless network. The computer device includes a handover (SH) proxy. The VoIP handover proxy is to maintain the transmission of the data application while the transmission and state of the data application switches from being transmitted over the first wireless network to being transmitted over a second wireless network. During the switch between wireless networks, the data application is unaware of the switch, and seamless mobility is achieved by using the VoIP handover proxy.