IAB Donor-DU BAP Tunneling for Seamless Inter-Donor Routing

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Solution Overview

Problem

Existing inter-CU migration procedures in IAB networks cause service interruptions and signaling storms due to the need for reconfiguring IP addresses of descendant nodes during inter-donor topology adaptation, especially in proxy-based solutions.

Innovation Solution

Implementing direct tunnels between source and target donor DUs and encapsulating BAP packets with additional headers to route traffic through a secondary donor without changing the IP addresses of descendant nodes, using GTP tunnels and BAP headers to maintain seamless communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If inter-CU migration procedures are implemented in IAB networks, then topology adaptation and load balancing are achieved, but service interruptions and signaling storms occur due to IP address reconfiguration of descendant nodes

Engineering Contradiction:

Improvetopology adaptationVSAvoidservice continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a tunnel mechanism as an intermediary between source and target donor DUs. This tunnel allows traffic to be forwarded without requiring descendant nodes to change their IP addresses or reconfigure their routing, thus enabling topology adaptation while maintaining service continuity. The tunnel acts as a mediator that decouples the migration process from the need for IP address reconfiguration.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the migration process into two independent parts: (1) establishing a tunnel between donor DUs for traffic forwarding, and (2) maintaining existing IP addresses of descendant nodes. This segmentation allows topology adaptation to proceed without triggering service interruptions or signaling storms related to IP address reconfiguration.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If IP addresses of descendant nodes are reconfigured during inter-donor topology adaptation, then routing to the new donor is achieved, but signaling overhead and service disruptions increase

Engineering Contradiction:

Improverouting flexibilityVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The tunnel mechanism serves as an intermediary that handles routing between source and target donor DUs without requiring descendant nodes to reconfigure their IP addresses. This eliminates the need for complex signaling procedures and reduces signaling overhead while maintaining routing flexibility through the tunnel endpoint configurations.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If proxy-based inter-donor topology adaptation is used, then load balancing between donors is achieved, but IP address reconfiguration of descendant nodes is required causing service interruptions

Engineering Contradiction:

Improveload balancingVSAvoidservice continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a tunnel as an intermediary that enables proxy-based inter-donor topology adaptation for load balancing without requiring IP address reconfiguration of descendant nodes. The tunnel forwards traffic between the source and target donor DUs, allowing load balancing while maintaining service continuity throughout the IAB network.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12593261B2Methods for inter IAB-donor-DU BAP tunneling

Publication Date: 2026.03.31 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is provided a method performed by a first donor distributed unit (DU) for routing traffic to a second donor DU in an Integrated Access Backhaul (IAB) network. The method may comprise: receiving an uplink (UL) packet, destined to the second donor DU, from an IAB node, which has a communication path to the second donor DU that is unavailable; appending a header pertaining to a tunnel to the UL packet; and sending the UL packet through the tunnel to the second donor DU, the tunnel being established between the first donor DU and the second donor DU.