LTE-WLAN Aggregation Handover Control
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Solution Overview
Problem
Handover and radio link failure in LTE-WLAN aggregation systems often result in compromised quality of service and wasteful network resource usage, particularly on the air interface, due to inadequate timing in deconfiguring or updating the LTE-WLAN service.
Innovation Solution
The implementation of a communication apparatus with a controller and transceiver that manages handovers and maintains user plane communication by identifying and transferring information about the second communication access point, allowing seamless handovers and radio link re-establishment without terminating the existing WLAN connection, thereby optimizing network resource usage and maintaining service quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE is handed over to an access point at the edge of WLAN or LTE cell coverage, then the UE can maintain connection to the network, but the UE may move outside the served area before the base station de-configures the LWA service, resulting in loss of connection and QoS failure
Solution Approach 1:
The base station proactively de-configures the LWA service when detecting that the UE is connected to an access point at the edge of coverage area, before the UE potentially moves outside the served area. This preliminary action prevents connection loss and QoS failure by removing the UE from LWA service in advance, allowing the base station to react to handover events without risking service disruption.
2Ease of operation
If the UE is handed over within the WLAN to an access point unable to provide the same QoS, then the handover can be completed, but the base station cannot de-configure or update the LWA service in time, causing QoS requirements to fail
Solution Approach 1:
The base station continuously monitors QoS parameters and handover status, and when detecting that the UE is connected to an access point unable to provide required QoS, the base station de-configures the LWA service. This feedback mechanism ensures that QoS requirements are maintained by dynamically adjusting the LWA service configuration based on real-time network conditions and access point capabilities.
3Reliability
If radio link failure occurs on the WLAN or LTE part of the LWA service, then the connection can be re-established, but the base station cannot act timely to maintain required QoS, and a potentially good WLAN connection must be dropped
Solution Approach 1:
The base station proactively de-configures the LWA service upon detecting radio link failure on either the WLAN or LTE part, before the UE can re-establish connection. This preliminary action prevents QoS failure and allows the base station to react to RLF events without delay, preserving potentially good WLAN connections that would otherwise be unnecessarily dropped during re-establishment procedures.
4Reliability
If the UE is handed over between LTE base stations, then the UE can maintain control plane connectivity, but unnecessary signaling occurs between the UE and serving base stations and between the UE and WLAN, especially when the current WLAN access point quality is sufficient
Solution Approach 1:
The patent separates the control plane handover procedure from the user plane LWA service configuration. During LTE base station handover, only the control plane connection is re-established with the new base station, while the LWA service and WLAN connection are preserved. This segmentation allows control plane connectivity to be maintained without triggering unnecessary user plane signaling and WLAN re-configuration, reducing signaling overhead and energy consumption.
Data Source
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AI summary
A communications system is described in which a base station controls interworking between a cell of the base station operating according to a first radio access technology and cells of access points operating according to a second radio access technology. The base station transmits control plane data to a mobile device in its cell, wherein the control plane data facilitates user plane communication by the mobile device, via a first access point. When the user plane communication has been handed over from the first access point to a second access point, the base station receives information identifying the second access point. Beneficially, the base station uses the received information for controlling the interworking and/or controlling a handover for the mobile device.