Cellular IAB Routing for Direct Inter-AP Backhaul Messaging

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Solution Overview

Problem

In cellular telecommunications networks, the use of single-hop relay nodes limits the capacity of wireless backhaul connections, particularly in multi-hop architectures, leading to inefficiencies in routing inter-AP messages and increased burden on wireless backhaul connections serving multiple IAB node branches.

Innovation Solution

Implementing a method for managing inter-AP message routing by storing and updating routing tables in IAB nodes to identify parent and child nodes, allowing direct message transfer between nodes without involving the donor IAB, thereby optimizing wireless backhaul connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If relay nodes are used to reduce backhaul expenditure, then capital expense is reduced, but message routing complexity increases

Engineering Contradiction:
Improvebackhaul expenditureVSAvoidmessage routing complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring routing tables in relay nodes during network setup. The donor base station provides routing information to relay nodes in advance, enabling them to make immediate forwarding decisions without complex real-time routing computations. This pre-establishment of routing paths simplifies ongoing message routing operations while maintaining the cost-effective relay node architecture.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple IAB nodes are deployed to increase network capacity, then overall capacity is improved, but wireless backhaul connection load increases

Engineering Contradiction:
Improvenetwork capacityVSAvoidwireless backhaul connection load
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies segmentation by dividing the network into hierarchical segments with clear parent-child relationships between IAB nodes. Each node is assigned to a specific parent node, creating segmented routing zones. This segmentation enables localized message forwarding within segments, reducing the need for messages to traverse entire multi-hop paths and thereby reducing overall wireless backhaul connection load while maintaining expanded network capacity.

Inventive Principle:
Principle #1Segmentation

3Productivity

If routing tables are implemented in IAB nodes, then message forwarding efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvemessage forwarding efficiencyVSAvoidrouting table management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies the intermediary principle by designating the donor base station as a central mediator that manages routing table distribution and updates for all IAB nodes. Rather than each IAB node independently managing complex routing tables, the donor base station acts as an intermediary that simplifies routing information and distributes it to appropriate nodes. This reduces the actual complexity at individual IAB nodes while maintaining overall forwarding efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4171104B1Cellular telecommunications network
Publication Date: 2025.08.06 BRITISH TELECOM PLC
  • EP4171104B1 patent drawingFigure 1
  • EP4171104B1 patent drawingFigure 2
  • EP4171104B1 patent drawingFigure 3

AI summary

This invention relates to a method of operating an Access Point, AP, in a cellular telecommunications network, the cellular telecommunications network having a plurality of APs and a core network, wherein the AP is connected to a neighbouring AP of the plurality of AP via a wireless upstream connection towards the core network, the method comprising the steps of: storing data identifying the neighbouring AP, a parent AP of the neighbouring AP, and a child AP of the neighbouring AP, wherein the neighbouring AP is connected to the parent AP via a wireless upstream connection towards the core network and is connected to the child AP via a wireless downstream connection away from the core network; generating an inter-AP message destined for the child AP of the neighbouring AP; determining that the child AP is a child AP of the neighbouring AP; and, in response, sending the inter-AP message to the neighbouring AP.