KR101514398B1 - Gateway in-vehicle based on virtual bus concepet and message transmission method thereof - Google Patents

Abstract

The present invention relates to a message transmitting method of a CAN-Ethernet gateway. The message transmitting method comprises the steps of: (a) if a plurality of messages are received from nodes existing in different CAN buses through a Ethernet backbone network, storing the received messages in a buffer; (b) competing the messages stored in the buffer for the transmitting timing according to a priority so that a message having a top priority occupies a CAN bus in which there is a destination node so as to be transmitted to the destination node. To the end, different CAN buses connected to the Ethernet backbone network by the gateway are configured as a single virtual bus to be transmitted according to the priority of the message.

Description

[0001] The present invention relates to a vehicle gateway of a virtual bus concept and a method of transmitting the message,

The present invention relates to a vehicle gateway, and more particularly, to a gateway for a vehicle, which is installed in a vehicle in which a plurality of networks are mixed and operates similar to a conventional CAN network by applying a virtual bus concept, To be transmitted in accordance with the order of priority, not the order of arrival of the messages.

CAN (Controller Area Network) is a network in which various ECUs (Electronic Control Units) in a vehicle are connected in parallel and is widely used in automobile networks today.

Figure 1 is an illustration of a typical CAN bus topology. Referring to FIG. 1, a general CAN protocol adopts a multi-master structure in which all ECUs connected to a bus perform a master role, and a CSMA-CA scheme is used for intervention in message transmission between ECUs . In this way, since messages are interfered with each other by their priorities, the messages having high priority are sequentially occupied and transmitted from the CAN bus.

However, in recent years, the number of electronic control units (ECUs) in a vehicle has increased and data traffic has increased due to real-time video transmission, so that it is difficult to cope with the conventional CAN only having a transmission bandwidth of 1 Mbps.

In order to apply such various contents, additional networks are installed in the automobile. Gateways are used to transfer data between heterogeneous networks using heterogeneous protocols within these vehicles.

In particular, attempts have been made to apply Ethernet (Ethernet) supporting cost-effective bandwidth as a backbone-network of CAN. As a result, the CAN-Ethernet Gateway for Ethernet and CAN connectivity is becoming a key module in next-generation automotive Ethernet.

The CAN-Ethernet Gateway connects the CAN bus to the Ethernet backbone.

FIG. 2 is a diagram illustrating a state in which first, second, and third CAN buses are connected using a gateway. Referring to FIG. 2, a message transmitted through one CAN bus is transmitted to a destination via a CAN-Ethernet gateway, an Ethernet switch connected to the gateway, and a gateway connected to another CAN bus as a destination.

It has been proposed that the CAN-Ethernet gateway according to the conventional studies processes the messages accumulated in the buffer in a first-in first-out (FIFO) manner. In the FIFO scheme, a message arriving at the gateway is first accumulated in the buffer, and the opportunity is received and transmitted. In this case, the priority of the message can only be considered on each CAN bus, and only after the message has passed through the gateway, it is prioritized by the arrival order. Therefore, priority is limited only between ECUs on the same CAN bus, and priority among ECUs connected to different CAN buses can not be guaranteed. In this case, a message having a high priority such as a time-critical control message may not be transmitted to a destination within a deadline due to a transmission delay. Such a situation can cause a problem that is directly related to the safety of a motor vehicle driver.

As described above, since the priority of the CAN-Ethernet gateways using the conventional FIFO scheme is not ensured between the ECUs on different CAN buses, when a message having a low priority blocks a message having a high priority . This blocking phenomenon occurs mainly in the buffer of the gateway.

Korean Patent Publication No. 10-2013-0016809

According to an aspect of the present invention, there is provided a gateway for connecting a CAN bus and an Ethernet backbone, the method comprising: receiving a message transmitted from a different CAN bus, And to provide the above objects.

According to a first aspect of the present invention, there is provided a method for transmitting a message between a first network bus and a backbone network, the method comprising the steps of: (a) Storing the received messages in a buffer when a plurality of messages transmitted from nodes existing on two network buses are received; (b) transmitting the messages stored in the buffer to the destination node such that the messages having the highest priority occupy the first network bus in which the destination node exists, by competing transmission timings in priority order; (c) repeating the steps (a) and (b) to cause a message having the highest priority among the messages accumulated in the buffer to be transmitted, And the second network buses are configured as a single virtual bus, according to the priority of the message.

In a message transmission method of a gateway according to the first aspect, the priority of the messages is determined by a source node of the message, the first and second networks are CAN (Controller Area Network) Ethernet, and the gateway is preferably a CAN-Ethernet gateway.

A gateway according to a second aspect of the present invention includes: a first interface unit connected to a backbone network connected to first network buses; A second interface unit connected to a second network bus to which a plurality of nodes are connected; A buffer for storing a plurality of messages received from different network buses through the first and second interface units; The transmission timing of the messages stored in the buffer is competing according to the priority order so that the message having the highest priority occupies the first network bus in which the destination node exists so that the message having the highest priority among the messages accumulated in the buffer And transmits the messages according to the priority regardless of the order in which the messages arrive at the buffer.

In the gateway according to the second aspect of the present invention, it is preferable that the backbone network is an Ethernet backbone network, the first and second network buses are CAN buses, and the automotive gateway is a CAN-Ethernet gateway.

According to the message transmission method of the gateway according to the present invention, the concept of the virtual bus is applied to the CAN-Ethernet gateway so that transmission contention occurs according to the priority regardless of the order in which the messages arrive inside the gateway. As a result, as shown in FIG. 5, the time-critical control messages are transmitted first compared to the general control messages, so that no transmission delay occurs in the conventional method.

Figure 1 is an illustration of a typical CAN bus topology.
FIG. 2 is a diagram illustrating a state in which first, second, and third CAN buses are connected using a gateway.
FIG. 3 is a conceptual diagram illustrating a virtual bus between a destination CAN bus and a source CAN bus to which a message transmission method of a gateway according to a preferred embodiment of the present invention is applied.
FIG. 4 is a timing diagram of message transmission on the CAN bus 3, which is a destination CAN bus when connected to a gateway using a conventional FIFO scheme, FIG. 5 is a timing chart of a message transmission when connected to a gateway to which a message transmission scheme according to the present invention is applied to be.

The message transmission method of the gateway according to the present invention is characterized in that messages transmitted from different CAN buses are transmitted in a priority order such that a CAN bus directly connected to a gateway and a plurality of CAN buses connected via an Ethernet backbone network are connected by a single virtual bus And then transmitted to the destination CAN bus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of transmitting a message of a gateway according to a preferred embodiment of the present invention and a gateway to which the method is applied will be described in detail with reference to the accompanying drawings.

FIG. 3 is a conceptual diagram illustrating a virtual bus between a destination CAN bus and a source CAN bus to which a message transmission method of a gateway according to a preferred embodiment of the present invention is applied. As shown in FIG. 3, applying the virtual bus concept, the source CAN buses, CAN buses 1 and 2, are virtually connected to the CAN bus 3, which is the destination CAN bus.

The CAN-Ethernet gateway according to the preferred embodiment of the present invention connects the CAN buses in which the source ECUs that transmit messages are present and the CAN buses in which the destination ECUs, which are the destination of the message, are virtually connected, and are connected to the gateway and the Ethernet backbone network Multiple CAN buses send messages in priority order.

A message transmission method of a gateway for connecting a vehicle network bus and an Ethernet backbone according to the present invention comprises the steps of: (a) receiving a plurality of messages from different network buses on an Ethernet backbone network, ; (b) competing messages stacked in the buffer according to a priority order, causing a message having the highest priority to occupy a vehicle network bus in which a destination ECU exists, and transmitting a message having a higher priority to a destination ECU; (c) repeating the steps (a) and (b) so that a message having the highest priority among the messages accumulated in the buffer is transmitted.

According to the message transmission method having the above-described configuration, a plurality of vehicle network buses connected to the gateway and the Ethernet backbone network are configured as a single virtual bus, so that the messages accumulated in the buffer of the gateway are transmitted in priority order.

The priority of the messages is preferably determined by the origin ECU of the message.

Preferably, the vehicle network is a CAN (Controller Area Network), the backbone network is Ethernet, and the gateway is a CAN-Ethernet gateway connecting an Ethernet backbone and a CAN bus.

4 and 5 are timing diagrams showing the situation where the ECUs on the CAN buses 1 and 2 transmit the message to the destination CAN bus 3 in the connection of FIG. 2. FIGS. 4 and 5 are timing charts of the conventional method and the present invention FIG. 2 is a diagram illustrating a message transmission timing at which a message is transmitted according to a method of FIG.

FIG. 4 is a timing diagram of message transmission on the CAN bus 3, which is a destination CAN bus when connected to a gateway using a conventional FIFO scheme, FIG. 5 is a timing chart of a message transmission when connected to a gateway to which a message transmission scheme according to the present invention is applied to be.

Referring to FIG. 4, the ECUs 3 and 4 directly connected to the CAN bus 3 first occupy the CAN bus 3 in timing. Thereafter, the message of the ECU 5 existing on the route closer to the CAN bus 3 is transmitted first, and then the message of the ECU 1 is transmitted and accumulated in the buffer of the gateway. Thereafter, similarly, the message of the ECU 6 is first put into the buffer, and the message of the ECU 2 arrives last and enters the buffer. Therefore, when the FIFO scheme is applied as it is, the messages of the ECUs 1 and 2 are blocked by other messages having lower priority, and the transmission delay occurs even though it is the time-critical control message having the highest priority.

Referring to FIG. 5 according to the present invention, the ECUs 3 and 4 directly connected to the CAN bus 3 first occupy the CAN bus 3 in timing. Thereafter, even if the message of the ECU 5 that is located closer to the CAN bus 3 on the route first arrives at the buffer and the message of the ECU 1 arrives next, the message of the ECU 1 is first transferred to the CAN bus 3 Lt; / RTI > Also, while the message of the ECU 1 is being transmitted, the message of the ECU 2 arriving at the buffer similarly occupies the CAN bus 3 before the ECU 5 according to the concept of the virtual bus, and then the messages of the ECUs 5 and 6 are sequentially transmitted through the CAN bus 3 . Therefore, in this case, the blocking phenomenon can be prevented by the low priority messages as in the case of the FIFO method, which becomes clearer as the number of ECUs increases.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various changes and modifications may be made without departing from the spirit and scope of the invention. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

The method according to the present invention can be applied to a CAN-Ethernet gateway for a vehicle.

Claims (7)

A message transmission method of a gateway connecting a first network bus and a backbone network in which a plurality of nodes exist,
(a) storing received messages in a buffer when a plurality of messages transmitted from nodes residing on different second network buses through a backbone network are received;
(b) transmitting the messages stored in the buffer to the destination node such that the messages having the highest priority occupy the first network bus in which the destination node exists, by competing transmission timings in priority order;
(c) repeating the steps (a) and (b) so that a message having the highest priority among the messages accumulated in the buffer is transmitted;
Wherein the first and second network buses connected to the backbone network by the gateway are configured as a single virtual bus and are transmitted according to the priority of the message. The method according to claim 1, wherein the priority of the messages is determined by a source node of the message. The method of claim 1, wherein the first and second networks are controller area networks (CAN). The method of claim 1, wherein the backbone network is Ethernet and the gateway is a CAN-Ethernet gateway. 5. The method according to any one of claims 1 to 4, wherein the node is an Electronic Control Unit (ECU).
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