AAA Server Mediator for 3GPP Non-3GPP Handover
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Solution Overview
Problem
Current wireless communication networks fail to provide seamless handover between different types of communication technologies, such as 3GPP and non-3GPP networks, leading to disconnection and IP address changes when user equipment (UE) roams, resulting in loss of service and error conditions.
Innovation Solution
A subscription server and mobility management devices are implemented to exchange control messages regarding UE connection status across different network types, maintaining connection status and IP addresses, and using timers to manage periodic updates and re-authentications, ensuring continuous service during handovers between 3GPP and non-3GPP networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE roams from 3GPP access to non-3GPP access, then the UE can utilize different access technologies for service, but the control node MME loses contact with the UE and implicitly detaches it, breaking seamless handover
Solution Approach 1:
The patent introduces an AAA server as an intermediary between the UE and the MME. When the UE roams to non-3GPP access, it maintains registration with the AAA server which continues to track its location and status. This intermediary allows the MME to indirectly monitor UE connectivity through the AAA server, preventing premature detachment while enabling flexible access technology selection.
Solution Approach 2:
The patent implements preliminary registration of the UE with the AAA server before roaming occurs. The AAA server pre-establishes tracking mechanisms and maintains UE context information in advance. When handover to non-3GPP access occurs, the pre-configured tracking allows the network to immediately locate and maintain connection with the UE, avoiding connection breaks.
2Adaptability or versatility
If the UE roams from non-3GPP access to 3GPP access, then the UE changes network access type, but periodic re-authentication fails causing AAA server and HSS to de-register the user, breaking seamless handover
Solution Approach 1:
The patent implements dynamic adjustment of re-authentication behavior based on UE mobility state. When the UE is detected to be roaming between access types, the system dynamically modifies re-authentication timing and requirements. This dynamic approach prevents premature de-registration by adapting authentication demands to the actual mobility scenario, maintaining continuous user registration status while allowing network access switching.
3Reliability
If the MME waits for periodic updates from idle UEs, then the MME can track UE status, but the timeout mechanism causes implicit detachment when UE roams to non-3GPP access where it cannot send updates
Solution Approach 1:
The AAA server serves as a mediator that receives periodic updates from the UE regardless of which access network the UE is using. The MME can rely on the AAA server to forward status information about the UE, eliminating the need for the MME to directly receive periodic updates from the UE. This intermediary approach enables reliable status tracking while supporting seamless roaming between 3GPP and non-3GPP networks.
Data Source
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AI summary
The present invention relates to a solution for handling seamless handover between a 3GPP network and a non-3GPP network or two non-3GPP networks. The solution uses a new state information informing about a UE being in an Idle state in relation to the network not currently communicating through. Thus the UE is not immediately detached from the old network but may keep a logical connection and quickly re-attach to the old network if of interest.