Mobile IAB Node F1 Connection Setup During Donor Migration

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Solution Overview

Problem

In cellular communication systems, especially in 5G NR networks, the migration of mobile IAB nodes from a source donor node to a target donor node poses challenges in establishing F1 connections, leading to potential service interruptions if the F1 SETUP REQUEST is not transmitted at the appropriate timing.

Innovation Solution

The communication control method involves the source donor node transmitting a new establishment request for F1 connection to the mobile relay node migrating to the target donor node, prompting the mobile relay node to transmit an F1 SETUP REQUEST message to establish the F1 connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the mobile relay node waits for migration indication from source donor node before establishing F1 connection, then connection establishment timing is synchronized, but service interruption occurs during migration

Engineering Contradiction:

Improveconnection establishment reliabilityVSAvoidservice interruption time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The source donor node sends a new establishment request message to the mobile relay node in advance before the actual migration occurs. This preliminary action allows the mobile relay node to prepare and establish the F1 connection with the target donor node proactively, rather than waiting passively for migration indication, thereby reducing service interruption time while ensuring connection reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system establishes a buffer mechanism where the source donor node anticipates the migration need and sends the new establishment request beforehand. This cushioning approach ensures that the F1 connection setup process is already underway or completed before migration actually occurs, preventing service gaps during the transition

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If the mobile relay node transmits F1 SETUP REQUEST immediately upon receiving new establishment request, then connection is established quickly, but connection may be established at inappropriate timing

Engineering Contradiction:

Improveconnection establishment speedVSAvoidconnection establishment timing accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The mobile relay node uses feedback from the source donor node's new establishment request message to determine the appropriate timing for transmitting the F1 SETUP REQUEST. The source donor node provides timing-related information or conditions in the request message, and the mobile relay node adjusts its transmission timing based on this feedback, ensuring both speed and timing accuracy

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the system uses traditional handover procedure for mobile relay node migration, then migration can be performed, but F1 connection establishment is delayed causing service interruption

Engineering Contradiction:

Improvemigration capabilityVSAvoidservice interruption duration

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

Instead of following the traditional handover sequence where connection establishment occurs after migration initiation, this invention performs the F1 connection establishment action preliminarily by having the source donor node send the new establishment request before migration completes. This reverses the traditional sequence and eliminates the service interruption gap

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention inverts the traditional handover procedure by sending the new establishment request from the source donor node to the mobile relay node in advance, rather than waiting for the target donor node to initiate connection setup after migration. This inverted sequence ensures connection is ready before migration, eliminating service interruption

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20250184844A1Communication control method

Publication Date: 2025.06.05 KYOCERA CORP

AI summary

A communication control method according to one aspect is a communication control method used in a cellular communication system. The communication control method includes transmitting, at a mobile relay node configured to migrate from a source donor node to a target donor node, an F1 setup request message for requesting establishment of F1 connection to the target donor node in response to reception of a predetermined message from the source donor node. Here, the predetermined message is a message representing one of a new establishment request of F1 connection for the target donor node and a migration indication to the target donor node.