IAB Network Handover Procedure for Route Change and Data Recovery
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Solution Overview
Problem
Current handover protocols in integrated access and backhaul networks fail to efficiently manage communication path changes, leading to unnecessary data forwarding and potential data loss during handovers of intermediate network nodes, as they do not effectively inform nodes about route changes or recover undelivered protocol data units.
Innovation Solution
An enhanced handover procedure is introduced, which includes informing relevant network nodes of route changes and implementing a peer-to-peer data delivery status reporting mechanism to recover undelivered protocol data units, preventing unnecessary forwarding and ensuring data integrity by retransmitting missed packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current handover protocols are used in IAB networks, then handover procedures can be executed, but unnecessary data forwarding occurs and data loss happens during intermediate node handovers
Solution Approach 1:
The source IAB node is informed of the handover before it occurs, allowing the node to stop forwarding data to the source IAB node proactively. This preliminary notification prevents unnecessary data forwarding and potential data loss by preparing the network infrastructure in advance of the actual handover event.
Solution Approach 2:
A feedback mechanism is implemented where the target IAB node reports data delivery status back to the source IAB node after handover. This feedback loop enables the source node to identify and retransmit any undelivered data, ensuring data integrity while avoiding redundant forwarding operations.
2Reliability
If current handover protocols are used in IAB networks, then handover can be performed, but undelivered protocol data units cannot be recovered
Solution Approach 1:
The target IAB node sends a feedback message to the source IAB node indicating which protocol data units were successfully received and which were not. This feedback enables selective retransmission of only the missing data units, ensuring complete data delivery without requiring retransmission of all data.
Solution Approach 2:
The system implements a mechanism to identify discarded (undelivered) protocol data units through feedback reporting, then recover them through targeted retransmission from the source IAB node to the target IAB node, ensuring no data loss during the handover process.
3Productivity
If route changes are not informed to relevant network nodes, then handover can occur, but nodes continue forwarding data along obsolete paths
Solution Approach 1:
Relevant network nodes are notified of the route change before the handover is complete, allowing them to update their forwarding tables in advance. This preliminary notification prevents data packets from being routed along obsolete paths, eliminating forwarding delays and maintaining network efficiency.
Solution Approach 2:
The network routing information is made dynamic through real-time updates to network nodes about handover events. Nodes can dynamically adjust their forwarding behavior based on current route information, ensuring data always follows the most efficient path without stagnating on obsolete routes.
Data Source
AI summary
An enhanced handover procedure is provided to facilitate communication routing changes in an integrated access and backhaul (IAB) network. In an IAB network a network node can be connected to the core network via multiple different paths, and when the path changes, (e.g., when an intermediate network node performs a handover procedure with another network node), messages can be sent to relevant network nodes informing them of the route change so as to reduce the number of protocol data units (PDUs) that are transmitted to network nodes that are no longer part of the communication path to the target network node. The network node that is no longer part of the communication path can also inform a parent node of which PDUs have been successfully transmitted to the target network node so that the parent node can retransmit the PDUs that were not transmitted successfully.