IAB Node Link Failure Management via BAP Path Rerouting
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Solution Overview
Problem
The existing Integrated Access and Backhaul (IAB) framework for wireless communication networks lacks efficient mechanisms for managing radio link failures and adaptations, leading to service interruptions and network congestion, as it relies on incomplete information for rerouting BAP packets and does not dynamically adapt to partial radio link deficiencies.
Innovation Solution
A method is proposed where IAB-nodes detect changes in link conditions and send specific indication messages providing detailed information about affected BH radio links, allowing for adaptive rerouting and configuration adjustments, including radio link quality, congestion levels, and path impact, enabling more efficient packet routing and network topology adaptations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the existing IAB framework uses basic RLF indication messages without detailed link information, then the system maintains simplicity in message structure, but it cannot make informed decisions about adaptive rerouting and suffers from service interruptions and network congestion
Solution Approach 1:
The indication message is segmented into multiple fields, each carrying specific link condition information (link quality, congestion level, path impact). This allows the system to transmit comprehensive information without creating a monolithic complex structure, as each field can be independently processed and utilized for specific routing decisions.
Solution Approach 2:
The enhanced indication message acts as an intermediary carrier that bridges the gap between simple detection and complex routing decisions. By embedding detailed link condition information in the message, it enables intermediate IAB-nodes to make informed rerouting decisions without requiring complex centralized control, thus reducing service interruptions and congestion.
2Reliability
If IAB-nodes systematically reroute all BAP packets to alternate paths upon detecting RLF, then service continuity is maintained, but network congestion increases on alternate paths and not all packets actually need rerouting
Solution Approach 1:
The patent applies local quality by enabling IAB-nodes to make localized routing decisions based on specific link condition information received in indication messages. Each node can assess whether its local traffic actually needs rerouting by examining path impact information, rather than blindly following systematic rerouting rules. This granular, location-specific decision-making maintains service continuity where needed while avoiding unnecessary rerouting that causes congestion.
Solution Approach 2:
Instead of systematically rerouting all BAP packets (excessive action), the patent enables partial rerouting only for packets affected by the detected link failure. The indication message provides path impact information that allows nodes to identify and reroute only the necessary subset of traffic, avoiding the congestion that results from rerouting all packets regardless of actual need.
3Loss of energy
If the IAB framework waits for complete RLF confirmation before triggering rerouting, then false rerouting is avoided, but service interruptions occur during the detection and confirmation period
Solution Approach 1:
The patent implements preliminary action by enabling IAB-nodes to proactively detect link condition changes and send indication messages before complete RLF occurs. This early detection allows receiving nodes to prepare alternate paths and begin rerouting in advance, reducing service interruption time. The indication message can trigger preliminary rerouting actions that are later confirmed or adjusted based on whether full RLF actually occurs, thus avoiding both interruptions and unnecessary rerouting.
Data Source
AI summary
In an IAB network, an IAB-node detects a deficiency or failure of one BH link. A BH RLF indication message is sent to its child IAB-nodes specifying the BAP paths that are impacted, a quality of those paths and the deficient radio link by indicating the other IAB-node sharing the link. Same message are transmitted to this sharing IAB-node, but also to the IAB-donor in order to adapt the routing configuration of the IAB-nodes to the topology. BAP packets for the impacted BAP paths are rerouted using alternative BAP paths. IAB-nodes receiving the BH RLF indication message also apply routing strategies for the impacted BAP paths, taking into account the indicated quality. A similar message is transmitted when the BH radio link experiences recovery, so that the IAB-nodes stop rerouting the BAP packets and the IAB-donor restore the original routing configuration.