IAB Relay Node Migration Using MT Identity to Resolve BAP Address Conflicts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In an integrated access and backhaul (IAB) network, when a distributed unit (DU) of a network node is migrated but the mobile termination (MT) is not, a conflict arises between backhaul adaptation protocol (BAP) addresses due to the lack of advance negotiation between different donor-central units (CUs), leading to communication errors.
Innovation Solution
The DU includes identification information of the MT and/or itself in a message to the target donor-CU, allowing the CU to determine a correspondence without relying on the BAP address, thereby resolving conflicts and ensuring accurate communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DU sends the F1 SETUP REQUEST message with the BAP address to the target donor-CU during migration, then the F1 connection can be established, but the BAP address may conflict with another IAB-node served by the target donor-CU, resulting in communication errors
Solution Approach 1:
The source donor-CU acts as an intermediary to coordinate BAP address allocation between the target donor-CU and the IAB-node. It receives the F1 SETUP REQUEST message containing the BAP address, determines whether the address conflicts with existing IAB-nodes under its management, and only permits the migration if no conflict exists. This intermediary verification mechanism prevents address conflicts without requiring complex pre-negotiation between donor-CUs.
2Reliability
If the target donor-CU and source donor-CU negotiate BAP address allocation in advance, then address conflicts can be avoided, but the migration process becomes more complex and time-consuming
Solution Approach 1:
The source donor-CU maintains a record of allocated BAP addresses for all IAB-nodes under its management in advance. When migration is requested, this pre-maintained address information is immediately available for conflict detection, eliminating the need for time-consuming real-time negotiation between donor-CUs during the migration process.
Solution Approach 2:
The source donor-CU autonomously performs the BAP address conflict detection and validation without requiring active participation or negotiation with the target donor-CU. The source donor-CU independently determines whether the migration can proceed based on its local address allocation records, simplifying the migration process and reducing time loss.
3Ease of operation
If the DU includes the BAP address in the F1 SETUP REQUEST message, then the target donor-CU can identify the IAB-node, but address conflicts with other IAB-nodes served by the target donor-CU may occur
Solution Approach 1:
The source donor-CU provides feedback by validating the BAP address in the F1 SETUP REQUEST message against its records of allocated addresses. It determines whether the address conflicts with existing IAB-nodes and controls whether the migration proceeds. This feedback mechanism ensures that only non-conflicting address assignments are permitted, maintaining communication reliability while preserving ease of node identification.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
This application provides a communication method and apparatus, to resolve a conflict between BAP addresses in a migration process of an mIAB-node in an IAB network. The method includes: If a first donor-CU is different from a second donor-CU, a distributed unit DU of a relay node determines to include a BAP address of the relay node in a first message, and to include first identification information of a mobile termination MT of the relay node and/or second identification information of the MT in the first message, where the first donor-CU is a target donor-CU to which the DU of the relay node is to be migrated, the second donor-CU is a donor-CU connected to the MT, and the BAP address is used for communication of the relay node in a topology managed by the second donor-CU. The DU sends the first message to the first donor-CU. According to the method, the identification information of the MT in the first message may be used to distinguish between the BAP address of the relay node and a BAP address of another relay node served by the first donor-CU, so that a conflict between the BAP addresses in a migration process of the relay node is resolved, and communication accuracy is ensured.