IAB Local Routing by Buffer Size for Handover Reliability

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Solution Overview

Problem

Existing cellular communication systems face challenges in efficiently managing handovers and load balancing in Integrated Access and Backhaul (IAB) nodes, particularly in multi-hop scenarios, which can lead to data loss and inefficient use of network resources.

Innovation Solution

The implementation of connection switching between donor gNBs in IAB nodes with transparent operations for user equipment (UE), along with dynamic load balancing through local routing based on capacity information and BH connection information, ensures seamless handovers and efficient data relay.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If connection switching between donor gNBs is implemented in IAB nodes, then handover reliability is improved, but device complexity increases

Engineering Contradiction:
Improvehandover reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism where the IAB node acts as a mediator between UE and donor gNBs during handover. The IAB node maintains transparent operations for UE while independently managing connection switching between donor gNBs, thus improving handover reliability without increasing UE complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the handover function into two parts: the IAB node handles the complex connection switching between donor gNBs, while the UE maintains simple transparent operations. This segmentation allows reliability improvement at the IAB node level without propagating complexity to the UE

Inventive Principle:
Principle #1Segmentation

2Productivity

If dynamic load balancing through local routing is implemented, then resource utilization is improved, but device complexity increases

Engineering Contradiction:
Improveresource utilizationVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic load balancing by enabling IAB nodes to adaptively select routing paths based on real-time capacity information and BH connection information. This dynamic adjustment optimizes resource utilization without requiring complex changes to UE, as the IAB nodes autonomously make routing decisions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent enables IAB nodes to autonomously perform load balancing operations using locally available capacity information and BH connection information. The IAB nodes self-adjust their routing decisions without external control, improving resource utilization while keeping the system simple for UE

Inventive Principle:
Principle #25Self-service

3Ease of operation

If transparent operations for UE are maintained during handover, then ease of operation is improved, but data loss may occur

Engineering Contradiction:
Improveease of operationVSAvoiddata loss
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by having the IAB node prepare and maintain buffer space before handover occurs. The IAB node proactively manages data buffering and forwarding in anticipation of connection switching, ensuring data is not lost while UE operations remain transparent and simple

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4178246B1IAB local routing conditioned by buffer size
Publication Date: 2025.09.24 KYOCERA CORP
  • EP4178246B1 patent drawingFigure 1
  • EP4178246B1 patent drawingFigure 2
  • EP4178246B1 patent drawingFigure 3

AI summary

In a first aspect, a communication control method is a communication control method used in a cellular communication system and includes performing, by a relay node including a user equipment under control of the relay node, connection switching from a first donor base station to a second donor base station, continuing Radio Resource Control (RRC) connection between the user equipment and the first donor base station via the second donor base station after performing of the connection switching, and transmitting, by the first donor base station to the user equipment via the second donor base station by using the RRC connection, a handover command that instructs the user equipment to perform a handover to the second donor base station.