LTE-WLAN Aggregation Handover Without WLAN Termination
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Solution Overview
Problem
Current 3GPP LTE-WLAN aggregation systems face challenges in optimizing mobility, particularly in scenarios with increased data rates and dense deployments, where existing handover procedures may disrupt wireless local area network (WLAN) connections, leading to inefficiencies and potential service disruptions.
Innovation Solution
The implementation of an eNodeB-triggered handover procedure that allows for inter-eNodeB handovers without terminating the WLAN connection, by transmitting specific messages to maintain the WLAN connection, including a WT ID and XwAP ID, and managing E-UTRAN radio access bearers and mobility sets to ensure seamless handover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures are used in LTE-WLAN aggregation systems, then handover between eNodeBs can be performed, but WLAN connections are disrupted causing service interruptions and reduced mobility performance
Solution Approach 1:
The patent segments the handover procedure into distinct phases: eNodeB-level handover signaling is separated from WLAN connection management. The WLAN connection is maintained independently through separate messaging (WT release request with keep indication, WT addition request) while eNodeB context is transferred, allowing handover without WLAN disruption
Solution Approach 2:
The patent performs preliminary actions by establishing WLAN connection parameters and WT context before the actual handover executes. The target eNodeB receives and stores WLAN aggregation configuration including WT identifier and XwAP ID in advance, so when handover occurs, the WLAN connection can be seamlessly maintained without interruption
2Productivity
If WLAN connections are terminated during handover to simplify procedures, then handover can be performed, but service quality deteriorates and user experience is degraded
Solution Approach 1:
The patent ensures continuity of useful action by maintaining the WLAN connection active throughout the handover process. The WT release request message includes a keep indication that prevents WLAN termination, and the WT addition request message re-establishes the connection at the target eNodeB, ensuring uninterrupted service while handover executes
Solution Approach 2:
The patent introduces the WT (WLAN Termination) as an intermediary entity that mediates between eNodeB handover signaling and WLAN connection maintenance. The WT manages the Xw interface and coordinates with both source and target eNodeBs to ensure WLAN connectivity persists through the handover transition
3Adaptability or versatility
If frequent WLAN terminations occur during handovers, then mobility management becomes simpler, but system performance deteriorates and deployment costs increase
Solution Approach 1:
The patent makes the handover procedure universal by designing it to work with existing WLAN aggregation configurations without requiring WLAN termination. The same handover messaging structure handles both cases where WLAN should be maintained and where it should be released, based on the keep indication parameter, providing flexible adaptability
Data Source
AI summary
As one aspect of mobility enhancement of 3rd generation partnership project (3GPP) long-term evolution (LTE)-wireless local area network (WLAN) aggregation, inter-eNodeB (eNB) handover without WLAN termination (WT) change is considered. A source eNB transmits a handover request message including a WT identifier (ID) and WT XwAP ID to a target eNB. The target eNB transmits a WT addition request message including the WT XwAP ID to a WT, and receives a WT addition request acknowledge message from the WT. The target eNB transmits a handover request acknowledge message indicating that a WT is kept to the source eNB. The source eNB transmits a WT release request message indicating that the WT is kept to the WT. The WT is a logical node that terminates a Xw interface on a WLAN.