C-V2X PathHistory Broadcasting During Pseudonym Certificate Changes

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Solution Overview

Problem

C-V2X communication technologies face challenges with communication congestion, vehicle tracking after pseudonym certificate changes, and excessive air resource utilization due to large BSM messages including PathHistory information, which affects vehicle safety and autonomous driving.

Innovation Solution

Implement methods to selectively broadcast PathHistory information in C-V2X messages, such as BSMs, only during pseudonym certificate changes and for a limited time, using vehicle computing devices to manage PathHistory transmission based on pseudonym certificate changes and tracking error thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If PathHistory information is included in all BSM messages, then vehicle tracking accuracy is improved, but air resource utilization deteriorates due to excessive bandwidth consumption

Engineering Contradiction:

Improvevehicle tracking accuracyVSAvoidair resource utilization

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent implements periodic transmission of PathHistory information by triggering its inclusion in BSM messages only during specific events (pseudonym certificate changes) rather than continuously in every message. This event-driven periodic approach maintains tracking accuracy when needed while significantly reducing overall air resource consumption during normal operations.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent extracts PathHistory information from the continuous stream of BSM messages and transmits it only during specific critical events (pseudonym certificate changes). By separating this optional information from the mandatory core message content, the system maintains tracking capability when necessary while minimizing bandwidth consumption during routine communications.

Inventive Principle:

Principle #2Taking out (Extraction)

2Loss of information

If PathHistory information is transmitted frequently, then vehicle tracking awareness is improved, but communication congestion worsens

Engineering Contradiction:

Improvevehicle tracking awarenessVSAvoidcommunication efficiency

Core Design Contradiction:

Loss of informationVSProductivity

Solution Approach 1:

The system employs event-triggered periodic transmission where PathHistory is sent only during pseudonym certificate changes rather than at every BSM interval. This selective periodic approach ensures tracking awareness is maintained during critical identity transitions while preventing communication congestion during stable operational phases.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies partial action by transmitting PathHistory information only for the minimum necessary duration (during certificate change events) rather than continuously. This partial transmission strategy provides sufficient tracking awareness during critical moments while avoiding the excessive communication load that would result from constant transmission.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If pseudonym certificate changes occur every 300 seconds, then vehicle privacy is protected, but vehicle tracking continuity deteriorates during certificate transitions

Engineering Contradiction:

Improveprivacy protectionVSAvoidtracking continuity

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by including PathHistory information in BSM messages immediately during pseudonym certificate change events. This advance provision of historical path data ensures that receiving vehicles can maintain continuous tracking awareness through the certificate transition period, bridging the gap that would otherwise occur during identity changes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

PathHistory information serves as an intermediary element during pseudonym certificate transitions. By providing this historical trajectory data during certificate changes, the system mediates between the need for privacy (frequent certificate changes) and tracking continuity, allowing vehicles to be reidentified through path history even when identity identifiers change.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4122229B1Method of efficiently providing pathhistory in c-v2x

Publication Date: 2025.11.26 QUALCOMM INC

Figure 1A~1B
Figure 1C
Figure 2

AI summary

Various embodiments provide methods, vehicle computing devices, storage media, and systems for briefly providing PathHistory information in Broadcast Safety Messages (BSMs) sent from a vehicle when PathHistory information is not required to be included in all BSMs. Various embodiments may include broadcasting BSMs including PathHistory information during a period of time following a change of the vehicle's pseudonym certificate and broadcasting BSMs without PathHistory information at all other times. Some embodiments may further include determining whether sufficient path history points are available for PathHistory information generation, accumulating path history points in response to determining that sufficient path history points are not available for PathHistory information generation, and broadcasting BSMs including PathHistory information during the period of time once sufficient path history points have been accumulated.