AVB Time Synchronization via RTC IP Packets
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Solution Overview
Problem
Current AVB technology faces challenges in synchronizing time across devices in a vehicle environment due to differences in network situations and the inability to implement the Ethernet AVB technology, which is hindered by the lack of AVBTP stack in various devices and hardware restrictions, leading to desynchronization issues that affect multimedia data consistency and user convenience.
Innovation Solution
A time synchronizing method and system where a vehicle's AVN receives and maps RTC time information messages from devices, continuously registers synchronized devices, calculates and sets synchronous time using time differences, and corrects time synchrony upon status changes or packet loss, utilizing an IP protocol-based RTC time information message to ensure precise synchronization without relying on NTP or AVBTP stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Ethernet AVB technology is implemented using standard AVBTP stack, then time synchronization precision is improved, but device compatibility and hardware requirements worsen due to lack of AVBTP stack in various devices
Solution Approach 1:
The patent introduces an intermediary approach by implementing a simplified time synchronization protocol that mediates between devices lacking AVBTP stack and the requirement for precise synchronization. The AVN acts as a mediator that collects RTC time information from multiple devices, performs centralized time difference calculations, and distributes synchronization corrections, thereby enabling precise time sync without requiring each device to implement the complex AVBTP stack.
Solution Approach 2:
The patent changes the synchronization parameter from requiring full AVBTP stack implementation to using basic RTC time information exchange. By modifying the synchronization approach to rely on readily available RTC timestamps and calculating time differences centrally at the AVN, the system achieves synchronization without the hardware restrictions imposed by standard AVBTP requirements.
2Reliability
If N RTC time information messages are continuously received before registration, then synchronization reliability is improved, but network traffic and processing overhead worsen
Solution Approach 1:
The patent applies partial action by requiring only N continuous RTC time information messages for registration rather than continuous synchronization messaging. Once registered, the system reduces messaging to periodic corrections only when status changes occur, thereby achieving reliable synchronization while minimizing network traffic and energy consumption.
Solution Approach 2:
The system implements periodic action by sending RTC time information messages at specific intervals rather than continuously. Time synchronization is performed periodically based on status changes or predetermined periods, reducing network traffic while maintaining synchronization reliability through the initial N-message verification process.
3Measurement precision
If time synchronization is performed frequently to maintain precision, then time sync accuracy is improved, but system complexity and processing load worsen
Solution Approach 1:
The patent applies preliminary action by performing time difference calculations and averaging during the registration phase when N messages are already being processed. The synchronous time is established in advance during registration, and subsequent corrections are only performed when status changes occur, reducing the need for frequent synchronization operations and lowering system complexity.
Solution Approach 2:
The system implements feedback by monitoring status changes and triggering time correction only when necessary. The AVN compares current RTC time information with stored synchronous time and performs corrections based on detected status changes or predetermined periods, maintaining time sync accuracy while avoiding unnecessary processing operations.
Data Source
AI summary
Disclosed are a time synchronizing method under a vehicle AVB environment and a system using the same. An AVN, which communicates with at least one device which is provided in a vehicle and performs a predetermined operation under an Ethernet AVB environment, synchronizes the at least one device by receiving a RTC time information message in the form of a RTC protocol packet which applies an IP protocol. Therefore, various services which synchronize a plurality of devices in the vehicle are provided, to improve convenience of a driver.