Method for deterministic wireless transfer of time-controlled real-time messages in a distributed real-time system

Patent metadata

Field	Value
Publication number	US-10285145-B2
Application number	US-201515316201-A
Country	US
Kind code	B2
Filing date	Jun 8, 2015
Priority date	Jun 6, 2014
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

The invention relates to a method for deterministic wireless transfer of time-triggered real-time messages in a distributed real-time system, which real-time system comprises a plurality of node computers and one or more base stations, which are arranged in an arena, wherein all node computers and base stations have a global time, wherein one or more real-time message sequences are periodically transferred in the arena, wherein a real-time message sequence consists of a time-triggered header message with variable length and a sequence of one or more time-triggered real-time messages with a priori known length, and wherein, at an a priori determined transmission time, the software of a T-node issues, to a communication controller thereof, the command to send the header message, and wherein the communication controller of the T-node starts to send the header message as soon as no activity is determined in the arena during an IFS, and wherein the sending of the header message is aborted at an a priori determined time-triggered abort time of the T-node, and wherein, in a command interval before the abort time of the header message, the software of the computer node that has to send the first real-time message of the real-time message sequence issues, to the communication controller thereof, the command to send the first real-time message of the real-time message sequence, and wherein, in the command interval before the termination of the first real-time message, the software of the computer node that has to send the following real-time message of the real-time message sequence issues, to the communication controller thereof, the command to send the following real-time message, and wherein this process is repeated until all real-time messages of a real-time message sequence have been sent.

First claim

The invention claimed is:

1. A method for deterministic wireless transfer of time-triggered real-time messages in a distributed real-time system comprising a plurality of node computers and one or more base stations, which are arranged in an arena, wherein all of the plurality of node computers and the one or more base stations have a global time, the method comprising:
transferring at least one real-time message sequence periodically in the arena, wherein the at least one real-time message sequence consists of a time-triggered header message with variable length and a sequence of the at least one time-triggered real-time message with a priori known length, and wherein, at an a priori determined transmission time, software of a T-node issues, to a communication controller thereof, a first command to send the time-triggered header message, and wherein the communication controller of the T-node starts to send the time-triggered header message as soon as no activity is determined in the arena during an Inter Frame Space (IFS), and wherein the sending of the time-triggered header message is aborted at an a priori determined time-triggered abort time of the T-node, and wherein, in a command interval before the abort time of the time-triggered header message, the software of a computer node that has to send a first real-time message of the at least one real-time message sequence issues, to the communication controller thereof, a second command to send the first real-time message of the at least one real-time message sequence, and wherein, in the command interval before the termination of the first real-time message, the software of the computer node that has to send a subsequent real-time message of the at least one real-time message sequence issues, to the communication controller thereof, a third command to send the subsequent real-time message, and wherein this process is repeated until all real-time messages of the at least one real-time message sequence have been sent.

2. The method of claim 1 , wherein a real-time message appears multiple times in the at least one real-time message sequence.

3. The method of claim 1 , wherein a length of the time-triggered header message is longer than a longest application message that is to be transported by the communication controller.

4. The method of claim 1 , wherein a transfer period for an entire time-triggered header message is longer than a time interval between the first command for sending the time-triggered header message and the abort time, at which the sending of the time-triggered header message is aborted.

5. The method of claim 1 , wherein the IFS between every two messages of the time-triggered real-time message sequence has a smallest value supported by a protocol.

6. The method of claim 1 , wherein a node computer of the plurality of computer nodes uses a known time of arrival of the first real-time message of the at least one real-time message sequence for synchronisation of its local clock.

7. The method of claim 1 , wherein the first real-time message of the at least one real-time message sequence is a beacon message of the network.

8. The method of claim 1 , wherein the T-node and the one or more base stations are synchronised externally.

9. The method of claim 1 , wherein the T-node and the one or more base stations are synchronised via a TTEthernet system.

10. The method of claim 1 , wherein a wireless data channel is provided in accordance with IEEE Standard 802.11 (WiFi).

11. A distributed real-time system, comprising
a plurality of node computers and one or more base stations, which are arranged in an arena, wherein all of the plurality of node computers and the one or more base stations have a global time; and
at least one real-time message sequence that is configured to be periodically transferred in the arena, wherein the at least one real-time message sequence consists of a time-triggered header message with variable length and a sequence of the at least one time-triggered real-time message with a priori known length,
wherein, at an a priori determined transmission time, software of a T-node is configured to issue, to a communication controller thereof, a first command to send the time-triggered header message,
wherein the communication controller of the T-node is configured to start to send the time-triggered header message as soon as no activity is determined in the arena during an Inter Frame Space (IFS),
wherein the sending of the time-triggered header message is aborted at an a priori determined time-triggered abort time of the T-node, wherein, in a command interval before the abort time of the time-triggered header message, the software of a computer node that has to send a first real-time message of the at least one real-time message sequence is configured to issue, to the communication controller thereof, a second command to send the first real-time message of the at least one real-time message sequence,
wherein, in the command interval before the termination of the first real-time message, the software of the computer node that has to send a subsequent real-time message of the at least one real-time message sequence is configured to issue, to the communication controller thereof, a third command to send the subsequent real-time message,
wherein this process is repeated until all real-time messages of the at least one real-time message sequence have been sent.

12. The real-time system of claim 11 , wherein the plurality of node computers and the one or more base stations have a global time.

13. The real-time system of claim 11 , wherein the T-node is configured for wireless transfer of time-triggered messages in the distributed real-time system, wherein a chipset for the wireless transfer is arranged in the T-node, and a physical connection between the chipset and an antenna of the T-node is configured to be interrupted by a time-triggered switch.

Assignees

• Fts Computertechnik Gmbh
• Tttech Computertechnik Ag

Inventors

• Kopetz Hermann

Classifications

• H04W88/08

  Access point devices · CPC title

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• H04W56/00

  Synchronisation arrangements · CPC title