Time synchronization and scheduling method for vehicular Ethernet

A technology of time synchronization and scheduling method, applied in the field of communication network, can solve problems such as failure to meet design requirements, degradation of scheduling communication performance, scheduling deviation, etc., to achieve the effect of guaranteeing real-time scheduling function, avoiding clock jitter, and improving real-time performance

Inactive Publication Date: 2018-06-15
TONGJI UNIV +1
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  • Application Information

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Problems solved by technology

However, link delays, switch forwarding delays, and clock jitter during network operation may lead to deviations or even failur

Method used

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  • Time synchronization and scheduling method for vehicular Ethernet
  • Time synchronization and scheduling method for vehicular Ethernet
  • Time synchronization and scheduling method for vehicular Ethernet

Examples

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Embodiment

[0043] The present invention relates to a time synchronization and scheduling method of vehicle Ethernet, such as image 3 As shown, the method includes the following steps:

[0044] Step 1. Time synchronization startup optimization:

[0045] Synchronous startup optimization is mainly done in two ways, including simultaneous:

[0046] (1) Save synchronization information locally and calibrate the local clock:

[0047] In the actual network operation process, the vehicle Ethernet network is static, such as ECU nodes, switch characteristics and cable length, etc. do not change during operation. Thus each link delay calculation result can be saved by storing on a flash drive and reused at start-up with previous measurements for skew correction at start-up clock.

[0048] Taking the actual running example as an example, in order to obtain the clock deviation e when the local storage method is not used, it is necessary to first calculate the link delay d through the high-precision...

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Abstract

The invention relates to a time synchronization and scheduling method for a vehicular Ethernet. The time synchronization and scheduling method for the vehicular Ethernet comprises the steps of: S1, time synchronization starting optimization: performing local clock deviation correction by calling locally stored link delay, simultaneously, shortening a node synchronization message period, and accelerating a synchronization process; S2, static master clock selection: determining synchronous messages of all nodes, and determining a clock having the highest priority as a master clock; S3, synchronous redundant path selection: performing redundant path selection by adopting a clock correction message section in the synchronous messages, and filtering the delay time; and S4, real-time double-window scheduling: distributing messages sent by sending nodes into three priority queues, and dividing time windows into two periods, so that messages of all the sending nodes are sent synchronously. Compared with the prior art, the time synchronization and scheduling method for the vehicular Ethernet disclosed by the invention has the advantages of improving the practical synchronization stability,ensuring real-time scheduling and the like.

Description

technical field [0001] The invention relates to the technical field of communication networks, in particular to a method for time synchronization and scheduling of the vehicle-mounted Ethernet. Background technique [0002] With the rapid development of automobile intelligence, vehicle Ethernet is developing rapidly. Its network protocol is Time-Sensitive Networking (TSN) protocol, which requires time-sharing scheduling of the network and can be applied to vehicle Ethernet networks. Better real-time performance, suitable for systems with high real-time requirements; TSN protocol does not depend on the upper layer protocol, and is transparent to the application layer. As the time base for real-time scheduling, the TSN protocol plays an important role in time synchronization. Among them, the most widely used protocol is IEEE 802.1as, that is, Precision Time Protocol (Precision Time Protocol, PTP) and an updated draft version. The protocol's strengths are support for multiple...

Claims

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Application Information

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IPC IPC(8): H04J3/06H04L12/841H04L12/851H04L12/863
CPCH04J3/0632H04J3/0638H04J3/0641H04J3/0667H04L47/24H04L47/283H04L47/6215H04L7/0004
Inventor 罗峰徐金鹏钱时菲王博文温泉傅卓
Owner TONGJI UNIV
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