IAB Backhaul Link Failure Feedback for Downlink Delivery Control
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Solution Overview
Problem
In integrated access and backhaul (IAB) networks, the IAB donor node struggles to accurately learn of the data transmission status, leading to poor user experience due to the complexity of multi-hop transmissions and the inability to control data transmission in a timely manner.
Innovation Solution
The IAB node triggers feedback of downlink data delivery status (DDDS) information to the IAB donor when a radio link failure (RLF) occurs, allowing the donor to timely adjust downlink transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wireless transmission is used for both access link and backhaul link in IAB network, then fiber deployment cost is reduced and network flexibility is improved, but the IAB donor node cannot accurately learn data transmission status and control transmission in a timely manner
Solution Approach 1:
The patent implements a feedback mechanism where the IAB donor node receives transmission status information from IAB nodes through uplink signaling. When data transmission fails or radio link failure occurs, the IAB node sends failure indication messages to the donor node, enabling the donor to learn transmission status and adjust scheduling decisions accordingly.
Solution Approach 2:
The patent introduces intermediate IAB nodes as mediators in the multi-hop transmission path. These intermediate nodes relay both data traffic and control signaling between the donor node and remote IAB nodes, enabling status information to be transmitted through the wireless backhaul links without requiring direct fiber connectivity.
2Adaptability or versatility
If wireless transmission is used for both access link and backhaul link in IAB network, then network flexibility is improved, but the IAB donor node cannot control data transmission in a timely manner
Solution Approach 1:
The patent implements preliminary actions by having the IAB donor node pre-allocate uplink resources for failure indication messages and pre-establish signaling paths through intermediate IAB nodes. When radio link failure or transmission failure occurs, the IAB node can immediately send failure indications using pre-configured resources, reducing the time delay in notifying the donor node.
Solution Approach 2:
The patent establishes real-time feedback loops where transmission status information flows back from IAB nodes to the donor node through uplink signaling. This enables the donor node to receive timely updates about transmission failures and radio link conditions, allowing for rapid adjustment of scheduling decisions and resource allocation.
3Area of stationary object
If multi-hop transmission is used in IAB network, then coverage area is extended to remote areas, but network topology becomes complex and transmission status monitoring becomes difficult
Solution Approach 1:
The patent segments the complex multi-hop network into hierarchical levels with the donor node at the root and intermediate IAB nodes as branches. Each IAB node independently manages its own backhaul link to the parent node and access links to child nodes or UEs, simplifying the monitoring task at each node while maintaining overall network connectivity across extended coverage areas.
Solution Approach 2:
The patent uses intermediate IAB nodes as mediators that relay both data traffic and control signaling between the donor node and remote parts of the network. These intermediate nodes simplify the topology from the donor's perspective by presenting a single-hop abstraction, while actually supporting multi-hop wireless backhaul paths to extend coverage to remote areas.
Data Source
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AI summary
The present invention provides a communications method and apparatus. The method includes: when an integrated access and backhaul IAB node detects that an RLF occurs on a first backhaul BH link, triggering, by the IAB node, feedback of DDDS information of the IAB node to an IAB donor node, and/or sending, by the IAB node, first indication information to a child node of the IAB node, where the first indication information is used to indicate the child node of the IAB node to trigger feedback of DDDS information of the child node to the IAB donor node; the first BH link is a communication link between the IAB node and a parent node of the IAB node; the DDDS information of the IAB node is used to indicate a status in which the IAB node sends data to UE; and the DDDS information of the child node is used to indicate a status in which the child node sends data to the UE. In the solutions, the IAB donor can learn, in a timely manner, that an RLF occurs on a backhaul link, and learn of a downlink delivery status for data transmission to the UE through the backhaul link on which the RLF occurs, so that the IAB donor controls downlink transmission to the UE.