Buffered Packet Forwarding After Handover Failure
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Solution Overview
Problem
Existing communication systems face issues with data loss during handover failures, particularly in scenarios where the connection setup to a target node fails, leading to undelivered buffered data that cannot be transmitted to user equipment, resulting in increased latency and impaired user experience.
Innovation Solution
Implement mechanisms to directly or indirectly forward buffered downlink user data from a target node to a re-establishment node upon handover failure, using tunnel endpoint identifiers (TEIDs) and address indications to ensure data is delivered to the user equipment via a re-establishment procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover failure occurs during connection setup to target node, then connection establishment fails, but buffered data is lost and cannot be transmitted to user equipment
Solution Approach 1:
The patent introduces a source node as an intermediary to forward buffered data from the target node to the user equipment when direct transmission fails. The source node receives a forwarding address indication from the target node and uses it to establish a forwarding path, ensuring data reaches the UE even when handover to target node fails.
Solution Approach 2:
The patent implements preliminary data buffering at the target node during handover preparation, and pre-establishes forwarding paths through the source node. The forwarding address indication is prepared in advance, enabling immediate data redirection when handover failure is detected without waiting for data loss to occur.
2Loss of information
If buffered data is forwarded through additional nodes during handover failure, then data loss is minimized, but transmission latency increases
Solution Approach 1:
The patent extracts only the necessary forwarding address information (tunnel endpoint identifier and IP address) from the full data path setup, allowing the source node to forward data directly to the UE using this minimal extracted information. This reduces the complexity and time of establishing forwarding paths while ensuring data delivery.
3Reliability
If complex forwarding mechanisms are implemented to recover buffered data, then data delivery reliability improves, but system complexity increases
Solution Approach 1:
The source node acts as a simple intermediary that only needs to receive the forwarding address indication from the target node and forward buffered data accordingly. This mediator approach simplifies the overall system by concentrating the forwarding intelligence in one node rather than requiring complex coordination between multiple nodes.
Solution Approach 2:
The source node performs multiple functions: it acts as both the original serving node during handover and as a data forwarding node when handover fails. This multi-functionality reduces the need for dedicated recovery mechanisms and simplifies the system architecture by reusing existing network elements.
Data Source
AI summary
A method, apparatus, and a computer-readable storage medium are provided for forwarding of buffered user data at a target node to a re-establishment node. In an example implementation, the method may include receiving, by a first network node, a handover cancel or an Xn-User plane address indication message from a second network node, the handover cancel or the Xn-User plane address indication message including tunnel addresses for one or more data radio bearers; and forwarding, by the first network node, buffered downlink packets to a third network node or the second network node, the forwarding based at least on the tunnel addresses. In an additional example implementation, the method may include sending, by a third network node, tunnel addresses for one or more data radio bearers to a second network node upon re-establishing of a radio resource control connection; and receiving, by the third network node, buffered packets at the first network node from a second network node or the first network node. In an additional example implementation, the method may include initiating, by a user equipment, a radio resource control re-establishment procedure with a third network node, the re-establishment procedure is initiated upon a handover failure of the user equipment from a second network node to a first network node; and receiving, by user equipment, buffered packets at the first node from a third network node.