Synchronization-Dependent Transmission for V2X Communication

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Solution Overview

Problem

In vehicle-to-everything (V2x) communication systems, the loss of synchronization between wireless devices due to lack of connectivity to external synchronization sources, such as cellular networks or GNSS, can lead to transmission failures, particularly in critical safety applications like collision warnings where low latency and reliability are essential.

Innovation Solution

A method for a wireless device to select a transmission format based on its estimated level of synchronization with available synchronization sources, such as GNSS or network entities, allowing it to adaptively choose parameters like modulation, coding schemes, and retransmissions to ensure robust communication even when external synchronization is lost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wireless devices rely on external synchronization sources (cellular network or GNSS), then synchronization accuracy is improved, but transmission reliability deteriorates when external sources are unavailable

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidtransmission reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary mechanism (autonomous synchronization mode with drift compensation) that mediates between the need for accurate synchronization and the need for reliable transmission when external sources are unavailable. The device uses its internal clock as an intermediary when external sources are lost, compensating for clock drift to maintain acceptable synchronization levels.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements dynamic adaptation by switching between synchronization modes based on availability of external sources. The device dynamically adjusts its transmission parameters and synchronization strategy depending on whether external synchronization sources are available, partially available, or completely unavailable, thereby maintaining reliability across varying conditions.

Inventive Principle:
Principle #15Dynamics

2Duration of action of stationary object

If wireless devices use internal clock for synchronization when external sources are unavailable, then transmission continuity is improved, but synchronization accuracy deteriorates due to clock drift

Engineering Contradiction:
Improvetransmission continuityVSAvoidsynchronization accuracy
Core Design Contradiction:
Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies beforehand cushioning by preparing compensation mechanisms in advance for clock drift. Before transmission, the device calculates and compensates for expected drift based on known clock characteristics, thereby cushioning against the degradation of synchronization accuracy over time and maintaining both continuity and acceptable accuracy.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If transmission parameters are optimized for high synchronization accuracy, then communication quality is improved, but robustness against synchronization loss deteriorates

Engineering Contradiction:
Improvecommunication qualityVSAvoidrobustness against synchronization loss
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements parameter changes by adjusting transmission parameters based on the current synchronization state. When synchronization is stable, parameters are optimized for high quality; when synchronization degrades or external sources are lost, parameters are changed to prioritize robustness and continuity, thereby adapting to different operational conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3372020B1Synchronization-dependent transmission for vehicle to anything communication
Publication Date: 2021.09.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3372020B1 patent drawingFigure 1
  • EP3372020B1 patent drawingFigure 2~3
  • EP3372020B1 patent drawingFigure 4

AI summary

A method and a device configured for selecting a transmission parameter in a wireless communication network are disclosed. According to one aspect, at least one transmission parameter is selected based at least upon an estimated level of synchronization for the first wireless device.