3GPP2 Home Agent Mobility Management for CDMA LTE Roaming

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Solution Overview

Problem

The transition to LTE networks poses a challenge in providing seamless mobility solutions between legacy CDMA and LTE networks, requiring costly and complex upgrades to existing infrastructure, such as upgrading PDSN to HRPD Serving Gateway and PGW with integrated Mobile IPv4 Home Agent functions, which is time-consuming and destabilizing.

Innovation Solution

A mobility solution that uses a collaborative 3GPP2 home agent with a logical interface to PDN gateway for roaming between CDMA and LTE networks, employing inter-process communication to maintain IP sessions across different networks without necessitating upgrades to PDSN or cumbersome linking of AAA elements, allowing for optimal routing and session continuity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If PDSN is upgraded to HRPD Serving Gateway and PGW with integrated Mobile IPv4 Home Agent functions, then mobility management capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvemobility management capabilityVSAvoidinfrastructure upgrade complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a new network element called the Mobility Management Entity (MME) that acts as an intermediary between the CDMA network and LTE network. The MME handles mobility management functions through inter-process communication with the Packet Data Serving Node (PDSN), eliminating the need to upgrade PDSN to HRPD Serving Gateway. This mediator approach resolves the contradiction by providing mobility management capability without requiring complex infrastructure upgrades to existing PDSN nodes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the mobility management function from the PDSN by introducing a separate MME entity. Instead of integrating mobile IPv4 home agent functions into the PDSN (which would require upgrades to HRPD Serving Gateway), the mobility management is segmented and handled by the MME through standardized interfaces with the PDSN. This segmentation reduces device complexity while maintaining adaptability.

Inventive Principle:

Principle #1Segmentation

2Productivity

If existing networks are converted to LTE networks, then network capacity and speed are improved, but coordination complexity increases

Engineering Contradiction:

Improvenetwork capacity and speedVSAvoidcoordination complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The MME is designed as a universal mobility management entity that can operate in both CDMA and LTE networks. It provides multi-functional capability by handling mobility management for users roaming between these different network types through standardized protocols. This universality reduces coordination complexity when converting existing networks to LTE while maintaining compatibility with legacy CDMA infrastructure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements feedback mechanisms through inter-process communication between the MME and PDSN, allowing real-time coordination during handovers. The system exchanges status information and routing updates through standardized interfaces, enabling smooth transition between CDMA and LTE networks without increasing coordination complexity.

Inventive Principle:

Principle #23Feedback

3Reliability

If inter-process communication is used to maintain sessions, then session continuity is improved, but communication overhead increases

Engineering Contradiction:

Improvesession continuityVSAvoidcommunication overhead

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The MME establishes and maintains session contexts in advance through inter-process communication with the PDSN. By pre-configuring routing information and session parameters before actual data transmission begins, the system reduces the need for continuous communication during data flow. This preliminary action ensures session continuity while minimizing communication overhead during active data transmission.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8195778B1System and method for providing mobility across access technologies in a network environment

Publication Date: 2012.06.05 CISCO TECHNOLOGY INC

AI summary

An example method includes receiving a packet for a flow associated with a subscriber; determining if a home agent element has a context for the flow by communicating a handover query to a network element; assigning an Internet protocol (IP) address for the subscriber in response to the home agent element not having the context for the flow; and creating a session for the subscriber, where the session is created using inter-process communication between the home agent element and the network element. The method can further include maintaining communications with a packet data serving node (PDSN) and an Authentication, Authorization, and Accounting (AAA) element in order to assist in roaming between a Long Term Evolution (LTE) network and a code division multiple access (CDMA) network. The inter-process communication is used to maintain the session for the subscriber when the subscriber is attached to different networks.