VRU ITS-S Passive Mode for C-ITS Radio Congestion

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Solution Overview

Problem

In Cooperative Intelligent Transport Systems (C-ITS), the breakdown of VRU clusters leads to a high number of simultaneous message transmissions by cluster members, causing radio communication congestion and instability in the system, particularly in dense areas like urban environments.

Innovation Solution

Implementing a method where VRU ITS-Ss set their operating mode to passive after determining they are reported in a Collective Perception Message (CPM), reducing the transmission of VRU Awareness Messages (VAMs) until the cluster is no longer reported in the CPM, thereby minimizing radio communication resources and analysis load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If VRU cluster members resume broadcasting individual VAMs after cluster break up, then individual VRU position information is improved, but radio communication congestion increases

Engineering Contradiction:

Improveindividual VRU position informationVSAvoidradio communication congestion

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary action by having the ITS-S set the operating mode to passive in advance after determining the VRU cluster is reported in a CPM. This prevents the harmful effect of simultaneous VAM transmissions before they can occur, while still allowing individual position information to be obtained through the CPM.

Inventive Principle:

Principle #10Preliminary action

2Loss of information

If VRU cluster members transmit individual VAMs after cluster break up, then VRU visibility is improved, but system stability deteriorates

Engineering Contradiction:

ImproveVRU visibilityVSAvoidsystem stability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The CPM serves as an intermediary that provides individual VRU position information without requiring simultaneous VAM transmissions from all VRU cluster members. By using the CPM as the intermediate information source, the system maintains VRU visibility while avoiding the stability issues caused by message flooding.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If all VRU cluster members broadcast VAMs simultaneously after cluster break up, then complete VRU coverage is improved, but radio resource consumption increases

Engineering Contradiction:

ImproveVRU coverageVSAvoidradio resource consumption

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The system merges the function of individual VAM transmissions with the CPM broadcasting. Instead of having each VRU cluster member transmit individual VAMs, the CPM consolidates the position information of multiple VRUs into a single message, reducing radio resource consumption while maintaining complete VRU coverage.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP4387281A1Improved cluster break up management within an intelligent transport system

Publication Date: 2024.06.19 CANON KK

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AI summary

At least one embodiment of a method of communication in an intelligent transport system, ITS, the method, to be carried out at a vulnerable road user, VRU, ITS station, VRU ITS-S, belonging to a cluster of VRUs, comprising determining that the VRU cluster has been at least partially reported in a collective perception message, CPM and setting an operating mode of the VRU ITS-S to a VRU passive mode comprising refraining the VRU ITS-S from broadcasting VRU awareness messages, VAMs, for a time period.