Radio Link Failure Handling in LTE Networks
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Solution Overview
Problem
In next-generation mobile networks, radio link failures (RLF) lead to prolonged network reconnection times and core network element occupation, as user equipment (UE) transitions from LTE_IDLE to LTE_ACTIVE state, lacking context information, resulting in increased interruption times and service degradation.
Innovation Solution
A method is implemented to detect and log RLF information, including timestamps and serving cell references, and correlate this with reconnection data to identify frequently affected cells, allowing for proactive context information transfer and optimized handover parameters, reducing reconnection times and data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile station performs a state transition from LTE_IDLE to LTE_ACTIVE state for reconnection after RLF, then the network reconnection process can be initiated, but the reconnection time increases to approximately 100 ms and core network elements are occupied
Solution Approach 1:
The patent applies preliminary action by having the eNodeB maintain and prepare context information for user equipment in the IDLE state before actual reconnection is needed. The base station logs RLF information and maintains context data locally, so when reconnection occurs, the context is already prepared and can be immediately activated without waiting for full core network involvement, thus reducing the 100 ms reconnection time.
Solution Approach 2:
The patent uses the eNodeB as an intermediary that maintains local context information for user equipment. Instead of requiring direct core network involvement for every reconnection, the eNodeB acts as a mediator that stores and manages context data locally, enabling faster reconnection by avoiding the full core network signaling path while still maintaining network control.
2Reliability
If the mobile station performs full network reconnection procedures after RLF, then complete network connectivity is restored, but the process occupies core network elements and causes service degradation
Solution Approach 1:
The eNodeB performs preliminary action by pre-maintaining context information for user equipment in the IDLE state and logging RLF information locally. This preliminary preparation ensures that when reconnection is needed, the context is already available at the base station, allowing reconnection to proceed without occupying core network elements for the entire reconnection process, thus maintaining core network availability for other services.
Solution Approach 2:
The patent extracts the context information management function from the core network and places it at the eNodeB level. By taking out the context maintenance capability from the core network and implementing it at the base station, the system reduces the burden on core network elements during reconnection while maintaining complete network connectivity restoration.
3Adaptability or versatility
If the mobile station rapidly leaves the radio coverage area of the base station, then mobility is enabled, but radio link failure occurs and connection loss ensues
Solution Approach 1:
The patent applies preliminary action by having the eNodeB pre-configure and maintain context information for user equipment before rapid movement occurs. When RLF happens due to rapid mobility, the pre-maintained context allows the base station to quickly re-establish connection without waiting for full reauthentication, thus maintaining connection stability even during rapid mobility scenarios.
Solution Approach 2:
The patent implements feedback by having the eNodeB log and store RLF information along with user equipment identifiers and cell references. This feedback mechanism allows the network to analyze RLF patterns and improve future handover decisions, while the maintained context information provides immediate feedback capability for rapid reconnection after mobility-induced failures.
Data Source
AI summary
A technique for handling radio link failure in a communication network (10) is provided. A method implementation of this technique comprises the steps of maintaining radio link failure information including the identifier of a user equipment (UE) effected by the radio link failure together with at least one of a time stamp of when the radio link failure was detected and a reference to a cell (C1) which was serving the user equipment (UE) before the radio link failure was detected, receiving reconnection information including an identifier of a reconnected user equipment (UE) effected by a radio link failure after the user equipment (UE) is reconnected to the communication network and correlating the radio link failure information with the reconnection information to obtain a correlation result.