LTE-WiFi Mobility Interfaces for Seamless Inter-System Handover
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Solution Overview
Problem
Existing methods for integrating cellular and WiFi networks result in resource-intensive operations and frequent interruptions in ongoing communications, particularly in scenarios involving inter-system mobility.
Innovation Solution
Implementing an S1a-C control plane interface between a trusted WLAN access network (TWAN) and a mobility management entity (MME) and an S1a-U user plane interface between the TWAN and a serving gateway (SGW) in the 3GPP core network, allowing for seamless handover and simultaneous dual connectivity between LTE and TWAN access networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing methods of integrating cellular and WiFi networks are used, then inter-system integration is achieved, but resource consumption increases and communication interruptions occur
Solution Approach 1:
The patent segments the integration architecture by introducing separate control plane (S1a-C) and user plane (S1a-U) interfaces between TWAN and EPC. This segmentation allows independent optimization of control signaling and data traffic, reducing overall resource consumption while maintaining integration capability.
Solution Approach 2:
The patent introduces the MME as an intermediary entity that mediates between TWAN and EPC. The MME handles authentication, authorization, and mobility management, reducing the signaling burden on the core network and minimizing resource consumption during inter-system operations.
2Adaptability or versatility
If existing methods of integrating cellular and WiFi networks are used, then inter-system integration is achieved, but communication interruptions occur
Solution Approach 1:
The patent establishes control plane connectivity and authentication through the S1a-C interface before user plane data transmission begins. This preliminary setup ensures that mobility management and network policies are pre-configured, preventing communication interruptions during actual data transfer.
Solution Approach 2:
The patent enables dynamic path selection and seamless handover between LTE and WiFi access networks. The system can dynamically switch between access networks based on availability and quality, maintaining communication continuity without interruptions during transitions.
3Loss of time
If core network signaling is minimized, then latency is reduced and scalability is improved, but handover management complexity increases
Solution Approach 1:
The MME acts as an intermediary that centralizes handover management functions. By handling authentication, authorization, and mobility decisions at the MME level rather than requiring extensive core network signaling, the system reduces latency while managing complexity through a dedicated intermediary entity.
Solution Approach 2:
The control plane interface establishes handover policies and permissions in advance through preliminary authentication and authorization. This pre-configuration reduces the complexity of real-time handover decisions by having predetermined rules and permissions already in place.
4Reliability
If dual connectivity is maintained simultaneously, then mobility robustness is enhanced, but resource consumption increases
Solution Approach 1:
The patent segments the dual connectivity architecture by maintaining separate control plane and user plane paths for each access network. This allows the system to manage multiple connections efficiently by handling control signaling independently from data traffic, reducing overall resource consumption while maintaining mobility robustness.
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AI summary
A system is disclosed for providing inter-system mobility in integrated LTE and WiFi systems. A control plane interface, referred to as the S1a-C interface, is defined between a trusted WLAN access network (TWAN) and a mobility management entity (MME) comprised in an LTE wireless access network. A user plane interface, referred to as the S1a-U interface, is defined between the TWAN and a server gateway (SGW) in the LTE wireless access network. The MME operates as a common control plane entity for both LTE and TWAN access, while the SGW operates as a user plane gateway for both LTE and TWAN. The integrated MME and SGW allow for user equipment (UE) to access the capabilities of a packet data network (PDN) through either the LTE access network or TWAN.