User Equipment Backup Cell Storage for Handover Failure Recovery
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Solution Overview
Problem
In cellular telecommunication networks, especially in high-speed scenarios and urban areas with micro cells, radio link failures due to loss of line-of-sight communication and increased handover frequencies lead to communication disruptions, which existing technologies struggle to address effectively.
Innovation Solution
A method for user equipment devices to periodically measure and store signal conditions of serving and neighboring cells, including backup cell information for fast re-establishment of connection using stored random access channel information, such as synchronization details and master information blocks, in a Random Access Memory to facilitate quick recovery in case of handover failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs normal handover procedure, then the handover process is simple and follows standard protocol, but the recovery time from radio link failure is long and communication sessions are lost
Solution Approach 1:
The patent applies preliminary action by having the UE store cell access information (including random access channel parameters, synchronization details, and master information blocks) of backup cells in advance during normal operation. When handover failure occurs, this pre-stored information enables immediate reconnection without requiring the UE to perform complete cell search and parameter acquisition from scratch, thus significantly reducing recovery time and maintaining communication session continuity.
2Speed
If the UE stores comprehensive cell access information for backup cells, then the reconnection speed is fast, but the memory consumption and device complexity increase
Solution Approach 1:
The patent applies partial action by storing only the essential cell access information parameters (such as random access channel configuration, synchronization information, and critical master information blocks) rather than all possible cell parameters. This selective storage approach provides sufficient information for rapid reconnection while minimizing memory consumption and avoiding the complexity of managing comprehensive cell databases for every possible backup cell.
3Reliability
If the UE measures and monitors signal conditions continuously, then the handover response is fast, but the energy consumption increases
Solution Approach 1:
The patent applies periodic action by having the UE measure and monitor signal conditions at regular intervals rather than continuously. The UE periodically evaluates signal strength of serving and backup cells, stores relevant cell access information when conditions warrant, and only activates full measurement and monitoring procedures when handover events are detected. This periodic approach maintains adequate handover response capability while significantly reducing energy consumption compared to continuous monitoring.
Data Source
AI summary
This disclosure teaches a method and apparatus for radio link failure recovery by a User Equipment (UE). The example UE includes one or more controllers that are configured to store cell access information for a target cell that is the target for an impending handover from a serving cell, and for a backup cell that is selected by the UE from among a set of neighboring cells that includes the target cell. Advantageously, in case the handover to the target cell fails, the one or more controllers are configured to retrieve the cell access information stored for the backup cell and to use that information for re-establishing connection in the backup cell. The UE selects the backup cell, for example, as the neighboring cell other than the target cell having the strongest signal conditions with respect to the UE.