X2' Interface for Seamless LTE to WLAN Handover
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Solution Overview
Problem
Existing methods for inter-system integration of cellular and WiFi networks are resource intensive and often result in interruptions in ongoing communications.
Innovation Solution
The implementation of an X2′ interface for communication between LTE wireless access networks and trusted WLAN access networks, enabling seamless handovers between the two systems by facilitating control plane signaling and user plane data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing methods for inter-system integration of cellular and WiFi networks are used, then integration is achieved, but the process is resource intensive and causes interruptions in ongoing communications
Solution Approach 1:
The patent segments the handover process into preparation (beforehand) and execution phases. The target access node prepares resources in advance, and the source access node executes the handover by switching the user equipment connection. This segmentation allows the system to achieve integration while minimizing resource consumption during actual communication by avoiding interruptions.
Solution Approach 2:
The patent implements preliminary action by having the target access node prepare for handover before the actual switch occurs. The target access node receives handover preparation requests, allocates resources, and configures parameters in advance. This preliminary preparation enables seamless handover execution without interrupting ongoing communications and reduces the resource burden during critical transition moments.
2Reliability
If existing methods for inter-system integration are used, then connectivity is established, but signaling must go deep into the core network causing interruptions
Solution Approach 1:
The patent introduces an intermediary mechanism where access nodes can directly communicate handover preparation requests and responses without necessarily routing all signaling through the core network. The source access node sends handover preparation requests to the target access node, which responds with allocation information. This intermediary approach maintains reliability by ensuring direct coordination between access nodes while reducing signaling latency by avoiding deep core network routing for every handover detail.
3Extent of automation
If handover procedures are implemented through core network signaling, then network control is maintained, but processing burden on the core network increases
Solution Approach 1:
The patent segments the handover control functions between access nodes and the core network. Access nodes handle the detailed handover preparation and execution logic locally, while the core network maintains overall session management and policy control. This segmentation reduces the processing burden on the core network by moving complexity to the edge devices (access nodes) while preserving necessary network control through simplified signaling.
Solution Approach 2:
The patent enables access nodes to perform handover preparation and execution autonomously based on local conditions and user equipment capabilities. The source access node initiates handover preparation requests, and the target access node independently allocates resources and configures parameters. This self-service capability reduces the processing burden on the core network while maintaining network control through standardized protocols and policy frameworks.
Data Source
AI summary
Systems and methods are disclosed for inter-system mobility in integrated LTE and trusted WLAN access networks (TWAN). An X2′ interface, adapted for both control plane and user plane communications, exists between an eNB and WLAN access point. A WLAN that has a UE attached thereto that is communicating with an EPC communicates over the X2′ interface with an C(H)eNB to handover communications from the WLAN to the (H)eNB. Similarly, an (H)eNB that has a UE attached thereto communicates over the X2′ interface with a WLAN to handover communications from the (H)eNB to the WLAN.