IAB Donor Discovery Signals for Efficient Parent Node Selection

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Solution Overview

Problem

In future radio communication systems, IAB nodes using NR communication struggle to identify suitable parent nodes, leading to unnecessary signal measurement and increased power consumption, and potential drops in communication throughput due to the inability to discern between IAB nodes with and without donor functionality.

Innovation Solution

Implementing a method for IAB nodes to determine whether another node can serve as a parent node by using a predetermined IAB donor discovery signal, such as an SSB or CSI-RS with distinct characteristics different from standard access UE signals, allowing nodes to differentiate between potential donors and non-donors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If IAB nodes measure all detected discovery signals (SSB/CSI-RS) to identify parent nodes, then the IAB node can discover potential parent nodes, but the IAB node cannot distinguish between IAB nodes with and without donor functionality, leading to unnecessary measurements and increased power consumption

Engineering Contradiction:
ImproveIAB node discovery accuracyVSAvoidIAB node power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the discovery signal into two distinct types: IAB node discovery signals (for discovering IAB nodes) and IAB donor discovery signals (for discovering IAB donors). This segmentation allows the receiving IAB node to identify and process only the relevant donor discovery signals, avoiding unnecessary measurements of non-donor signals and thereby reducing power consumption while maintaining accurate donor identification.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary indicator (such as a specific field in the signal or a reference signal indicator) that acts as a marker to identify whether a discovery signal is transmitted by an IAB node or an IAB donor. This intermediary enables the receiving node to quickly distinguish donor signals from non-donor signals without performing full measurements on all detected signals, thus reducing power consumption while preserving measurement precision for relevant signals.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If IAB nodes attempt to connect to all detected IAB nodes, then the IAB node can establish potential backhaul connections, but the IAB node may waste resources connecting to nodes that cannot serve as parent nodes

Engineering Contradiction:
ImproveBackhaul connection establishmentVSAvoidConnection establishment time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the transmitting node embed an identifier or indicator in the discovery signal that预先 indicates its capability to serve as a parent node (IAB donor). The receiving node uses this pre-provided information to filter out unsuitable nodes before attempting connection, avoiding wasted time on futile connection attempts and accelerating the establishment of valid backhaul connections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of having the receiving node determine whether a detected node is a donor through measurement and inference, the patent inverts the approach by having the transmitting node explicitly indicate its donor status in the discovery signal. This inversion simplifies the receiving node's task and enables faster, more accurate identification of suitable parent nodes, improving connection establishment productivity while reducing time loss.

Inventive Principle:
Principle #13The other way round (Inversion)

3Device complexity

If IAB nodes use standard SSB or CSI-RS for discovery, then the discovery process is simple, but the IAB node cannot differentiate between donor and non-donor nodes

Engineering Contradiction:
ImproveDiscovery signal structureVSAvoidDonor functionality information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent embeds additional information (donor indicator) within the existing discovery signal structure (SSB or CSI-RS), similar to nested dolls. The discovery signal maintains its standard form for compatibility but contains an embedded indicator that provides donor functionality information. This nested approach increases the information content without significantly increasing overall signal complexity, allowing differentiation between donor and non-donor nodes while preserving the simplicity of the base discovery mechanism.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent changes a specific parameter of the discovery signal (such as adding a field in the physical layer or modifying a reference signal indicator) to encode donor functionality information. This parameter change allows the signal to carry additional meaning without fundamentally altering the discovery signal structure, maintaining simplicity while preventing information loss about donor status.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3843463B1Wireless communication device and wireless communication method
Publication Date: 2025.12.17 NTT DOCOMO INC
  • EP3843463B1 patent drawingFigure 1
  • EP3843463B1 patent drawingFigure 2
  • EP3843463B1 patent drawingFigure 3

AI summary

An IAB donor is properly grasped. A radio communication apparatus according to one aspect of the present disclosure includes a transmitting/receiving unit that communicates with an integrated access backhaul (IAB) node, and a control unit that determines whether or not the IAB node has a function of an IAB donor based on a predetermined signal or channel received from the IAB node.