IAB Handover Signaling to Reduce Packet Loss and Service Disruption
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Solution Overview
Problem
Existing mobile communication technologies face challenges in managing packet loss during handover in integrated access and backhaul (IAB) deployments, particularly in high-speed scenarios like moving vehicles, leading to signaling overhead and disrupted service continuity.
Innovation Solution
Implementing techniques for IAB nodes to manage handover by sending stop indications, reconfigurations, and delivery status information, using flags and markers in packet headers, and configuring backhaul channels to optimize data forwarding and retransmission in IAB deployments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IAB nodes continue data forwarding during handover without stop indications, then service continuity is maintained, but packet loss increases due to routing conflicts and duplicate transmissions
Solution Approach 1:
The source donor CU sends a stop indication to the source IAB node before the handover is complete, preliminarily stopping data forwarding on the source path. This prevents packet loss from routing conflicts and duplicate transmissions while the UE is being transferred to the target donor CU.
Solution Approach 2:
The handover status is fed back to the source donor CU, which then triggers the stop indication. This feedback mechanism ensures that data forwarding is stopped at the appropriate moment - after handover initiation but before complete transfer - resolving the contradiction between maintaining service continuity and preventing packet loss.
2Reliability
If IAB nodes send frequent handover indications and stop indications, then packet loss is reduced, but signaling overhead increases
Solution Approach 1:
The stop indication is sent preliminarily at a predetermined time after handover initiation, rather than waiting for complete handover. This timing optimization reduces the number of retransmission requests needed while still preventing packet loss, thereby reducing signaling overhead.
Solution Approach 2:
The IAB node autonomously stops data forwarding upon receiving the stop indication, without requiring additional confirmation messages. This self-service mechanism reduces signaling overhead while ensuring reliable packet delivery.
3Loss of substance
If IAB nodes stop data forwarding early during handover, then packet loss is minimized, but service continuity is disrupted
Solution Approach 1:
The stop indication is sent at a predetermined time after handover initiation, which is preliminary enough to prevent packet loss but late enough to maintain service continuity. This timing balance ensures that the UE has already been transferred to the target donor CU before the source IAB node stops forwarding.
Solution Approach 2:
The data forwarding stop timing is dynamically adjusted based on handover progress. The system transitions from continuous forwarding to stopped forwarding at the optimal moment, balancing packet loss prevention with service continuity maintenance.
Data Source
AI summary
Methods, apparatus, and systems for reducing packet loss in wireless systems during handover, where one or more user equipment or mobile terminals are connected to an integrated access and backhaul node. The disclosure relates to continuing uplink (UL) and maintain service continuity in an integrated access and backhaul (IAB) system.