LTE Handover Failure Reporting via RLF Indicators
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Solution Overview
Problem
In LTE systems, network servers face challenges in collecting information about communication call drops due to handover failures and secondary cell group change failures, as UE does not include relevant information in radio link failure reports, hindering correct network operations.
Innovation Solution
A communication device and method that transmit specific messages to base stations indicating handover failures and radio link failures, allowing network servers to generate call drop analysis reports and improve communication handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the UE transmits only standard RLF reports without additional handover failure information, then the message format remains simple and compatible with existing protocols, but the network server cannot collect information about call drops caused by handover failures
Solution Approach 1:
The RLF report is segmented into standard fields and additional information fields. The additional information includes a handover failure indicator and bearer type information, separated as distinct elements within the overall report structure. This allows the network to receive both standard and enhanced information without disrupting existing protocol compatibility.
Solution Approach 2:
The handover failure information is extracted as a separate indicator within the RLF report structure. By taking out the handover failure indication and bearer information as distinct extractable elements, the patent enables targeted collection of handover failure data while maintaining the overall integrity and compatibility of the standard RLF report format.
2Reliability
If the network implements dual connectivity with SCG change, then the system capacity and coverage are improved, but the network cannot collect information about call drops caused by SCG change failures
Solution Approach 1:
The UE is pre-configured with bearer type information indicating whether QCI 1 bearers are configured before handover or SCG change operations. This preliminary information is stored and automatically included in failure reports when handover or SCG change failures occur, enabling the network to proactively identify and analyze call drop causes without requiring additional real-time signaling.
Solution Approach 2:
The patent implements a feedback mechanism where the UE includes bearer type information and handover failure indicators in RLF reports transmitted back to the network. This feedback loop enables the network server to collect and analyze information about SCG change failures and handover failures, allowing for improved network operations and reliability.
3Measurement precision
If the UE includes detailed bearer information in failure reports, then the network can accurately analyze call drop causes, but the message size and processing complexity increase
Solution Approach 1:
The patent applies local quality by including detailed bearer information (such as QCI 1 bearer presence) only in specific contexts where handover failure analysis is needed, rather than always including all possible information. The bearer type information field is selectively populated based on the failure scenario, providing precise information where needed while avoiding unnecessary data transmission in other cases.
Data Source
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AI summary
A communication device for handling a handover failure comprises a storage unit for storing instructions and a processing circuit coupled to the storage unit. The processing circuit is configured to execute the instructions stored in the storage unit. The instructions comprise transmitting at least one packet of a communication call via a first bearer to a first base station (BS); receiving a handover command from the first BS, wherein the handover command hands over the first bearer to a second BS; performing a handover from the first BS to the second BS; determining that a handover failure of the handover occurs; and transmitting a first message to a third BS, wherein the first message comprises first information which indicates the handover failure and presence of the first bearer.