User-Initiated IP Handoff Between Heterogeneous Wireless Networks
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Solution Overview
Problem
Current systems lack the capability to transfer an existing internet protocol (IP) session between two terminals operating under different technology standards and with different IP addresses, limiting seamless handoff between systems such as WLAN and UMTS or CDMA2000 and UMTS.
Innovation Solution
The method enables IP traffic handoff between terminals with different technology standards and IP addresses by allowing user-initiated or network-solicited handoff procedures, utilizing optimized routing mobile IP (MIPv4) to reroute sessions from one terminal to another, including activation of packet data protocol contexts as needed, without requiring changes to the WLAN system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IP traffic handoff is performed between terminals with different technology standards and IP addresses, then seamless connectivity between different systems (WLAN, UMTS, CDMA2000) is achieved, but system complexity and routing optimization requirements increase
Solution Approach 1:
The patent introduces a Home Agent (HA) as an intermediary entity that manages IP address binding and routing for mobile terminals across different networks. The HA receives binding updates from mobile terminals, stores binding information, and intercepts/IPsec tunnels packets to forward them to the correct terminal regardless of which network (WLAN, UMTS, CDMA2000) the terminal is currently attached to. This intermediary abstraction layer enables seamless handoff between different technology standards without requiring direct complex interactions between all possible network combinations.
2Reliability
If optimized routing mobile IP is used to transfer sessions between different IP addresses, then uninterrupted service is maintained, but routing complexity and message forwarding requirements increase
Solution Approach 1:
The patent implements preliminary action by establishing IPsec security associations and pre-configuring routing rules before handoff occurs. When a mobile terminal moves between networks, the Home Agent has already stored binding information and pre-established security contexts, allowing rapid interception and tunneling of packets without interruption. The binding update mechanism pre-registers the terminal's current care-of-address with the HA, so routing can be immediately adjusted without service disruption.
3Ease of operation
If user-initiated or network-solicited handoff procedures are implemented, then user control and network optimization are achieved, but signaling overhead and handoff procedure complexity increase
Solution Approach 1:
The patent employs periodic action through network-solicited handoff procedures where the network periodically queries or triggers handoff decisions based on terminal location, network conditions, and service requirements. This periodic network-initiated approach complements user-initiated handoffs by automatically optimizing routing based on current network state, reducing the need for frequent user decisions and minimizing handoff delays through proactive network management.
Data Source
AI summary
Apparatus and method by which Internet Protocol (IP) traffic can be transferred (i.e. handoff) between two different terminals operating according to two different technology standards in two different systems with two different IP addresses. For example, a session handoff can be made between a terminal in Wireless Local Area Network (WLAN) a terminal in a 3GPP UMTS or between a terminal in CDMA2000 and a terminal in a 3GPP UMTS. These terminals can be either physically separate entities or logical entities that are encapsulated within a common enclosure.