Home Agent NAI Correlation for Seamless Wireless Handoffs

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Solution Overview

Problem

Wireless communication devices (WCDs) face challenges in maintaining continuous communication sessions during vertical handoffs between different wireless networks, particularly when using different network access identifiers (NAIs), which can lead to service disruptions and noticeable delays.

Innovation Solution

A method where a home agent correlates multiple NAIs used by a WCD, maintaining a persistent home IP address (HOA) by verifying associations with an authentication server, allowing seamless handoffs between wireless networks while keeping the HOA assignment consistent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a WCD uses different NAIs for different wireless networks to maximize coverage and support vertical handoffs, then the device can access multiple network types (3G, 4G), but the communication sessions may be interrupted and service disruptions occur during handoffs

Engineering Contradiction:

ImproveAbility to access multiple wireless network typesVSAvoidContinuity of communication sessions

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The home agent acts as an intermediary between the WCD and correspondent nodes, maintaining a persistent binding that associates the WCD's home IP address with multiple NAIs. When the WCD handoffs between networks and presents a new NAI, the home agent intercepts the binding update, verifies the NAI through authentication server, and maintains the same home IP address binding, thereby preventing session interruption.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The home agent is designed to handle multiple NAIs for a single WCD, making it universally capable of managing bindings across different network types. The home agent can correlate different NAIs to the same WCD and maintain a single persistent binding, allowing the system to support vertical handoffs between 3G, 4G, and other network types without disrupting sessions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If the WCD changes its home IP address when switching NAIs during vertical handoffs, then the NAI change is reflected in the network, but the TCP/UDP communication sessions are abruptly terminated causing noticeable delays

Engineering Contradiction:

ImproveSimplicity of NAI change handlingVSAvoidService disruption time during handoff

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The home agent pre-establishes a persistent binding that can accommodate multiple NAIs before the handoff occurs. When the WCD presents a new NAI during handoff, the home agent already has the binding structure in place to absorb the NAI change without requiring a new home IP address assignment, thereby preventing session termination and avoiding service disruption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The home agent maintains continuous binding information that persists across NAI changes and network handoffs. By keeping the binding active and updating only the NAI association rather than resetting the home IP address, the system ensures continuous communication sessions without interruption, eliminating noticeable delays during vertical handoffs.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If the home agent stores and correlates multiple NAIs for a single WCD, then seamless vertical handoffs can be achieved, but the complexity of the authentication and binding management system increases

Engineering Contradiction:

ImproveContinuity of communication sessionsVSAvoidComplexity of home agent binding management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The home agent merges multiple NAI associations into a single binding structure for each WCD. Instead of creating separate bindings for each NAI, the system combines them into one unified binding that correlates all NAIs to the same home IP address, simplifying the management of multiple network identities while maintaining session continuity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system implements feedback mechanisms where the home agent receives binding update requests from the WCD, verifies the presented NAI through the authentication server, and updates the binding accordingly. This feedback loop ensures that only authorized NAIs are associated with the WCD's home IP address, maintaining security while managing complexity through structured verification processes.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9043473B1Methods and systems for authenticating a device with multiple network access identifiers

Publication Date: 2015.05.26 SPRINT SPECTRUM LLC

AI summary

Methods, systems, and devices are presented that allow a wireless communication device (WCD) to use multiple access identifiers (NAIs) in conjunction with a communication session between the WCD and a home agent. The home agent may maintain a binding that reflects the state of the session. Accordingly, the binding may contain a home IP address (HOA) as well as a first NAI. The home agent may then receive a registration request message containing the HOA and a second NAI. In order to avoid potential hijacking attacks from entities other than the WCD, the home agent may, in conjunction with an authentication server, attempt to validate that that first NAI and second NAI are both associated with the WCD. If this is the case, the home agent may update the binding to reflect that the second NAI is associated with the session, and the home agent may maintain the session so that the WCD does not suffer an appreciable interruption in service.