Handover Failure Recovery via Source Node Context Forwarding
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Solution Overview
Problem
Current handover procedures in wireless communication networks, such as E-UTRAN, are not entirely reliable due to radio link failures, leading to potential call drops and decreased user satisfaction, as they often require re-establishing communication connections when a mobile terminal experiences poor channel conditions or other factors.
Innovation Solution
A method and apparatus that facilitate handover failure recovery by enabling a target node to receive identity information from a source node about the mobile terminal involved in the handover, allowing the target node to establish communication based on the access stratum configuration information used by the source node, thereby enabling efficient recovery from handover failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mobile terminal experiences radio link failure before receiving handover command, then communication connection is lost with source base station, but full re-establishment of communication context parameters is required at target base station
Solution Approach 1:
The source base station performs preliminary actions by forwarding access stratum configuration information to the target base station before the handover is actually executed. This advance preparation ensures that when the mobile terminal experiences radio link failure and needs to reconnect, the target base station already has the necessary context information ready, eliminating the need for time-consuming full re-establishment procedures.
Solution Approach 2:
The source base station acts as an intermediary by transmitting the mobile terminal's access stratum configuration information to the target base station. This intermediary action bridges the information gap that would otherwise require the mobile terminal to fully re-establish its communication context, thereby reducing re-establishment time and improving handover reliability.
2Reliability
If full re-establishment of communication context parameters is performed after radio link failure, then communication can be re-established, but handover process complexity increases
Solution Approach 1:
The invention extracts the access stratum configuration information from the source base station and transfers it to the target base station in advance. By taking out this critical information beforehand, the complex full re-establishment procedure is replaced with a simpler context restoration process, reducing handover procedure complexity while maintaining communication recovery capability.
Solution Approach 2:
The source base station creates a copy of the mobile terminal's access stratum configuration information and sends it to the target base station. This copying approach allows the target base station to restore the communication context without requiring the mobile terminal to perform complex re-establishment procedures, thereby simplifying the handover process while ensuring reliable communication recovery.
3Reliability
If access stratum configuration information is forwarded from source node to target node, then recovery from handover failure is improved, but information transmission overhead increases
Solution Approach 1:
The source base station performs the preliminary action of forwarding access stratum configuration information to the target base station before handover failure occurs. This advance transmission ensures that when recovery is needed, the information is already available at the target node, improving handover failure recovery while the overhead is incurred only once during the preparation phase rather than repeatedly during re-establishment.
Data Source
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AI summary
An apparatus for facilitating handover failure recovery may include a handover management element configured to receive, at a target node, a handover request from a source node regarding the handover of communications with a mobile terminal. The handover request may include identity information indicative of the mobile terminal. The identity information may be the identity information used to identify the mobile terminal to the source node during establishment of the original connection between the source node and the mobile terminal. The handover management element may be further configured to receive a request for a connection from the mobile terminal subsequent to a radio link failure and prior to handover completion. Based on matching the identity information from the request for connection and the identity information received from the source node, the target node may establish communication with the mobile terminal based on access stratum configuration information used by the source node.