COMMUNICATION APPARATUS, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

• US 20110047244A1
• Filed: 07/10/2009
• Published: 02/24/2011
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Nagoya University, Autonetworks Technologies, Ltd. (Sumitomo Corporation), Sumitomo Electric Industries Limited (Sumitomo Corporation), Sumitomo Wiring Systems Limited (Sumitomo Corporation)
• Original Assignee: Nagoya University, Autonetworks Technologies, Ltd. (Sumitomo Corporation), Sumitomo Electric Industries Limited (Sumitomo Corporation), Sumitomo Wiring Systems Limited (Sumitomo Corporation)
• Inventors: Kurachi, Ryo, Miyashita, Yukihiro, Takada, Hiroaki
• Granted Patent: US 8,626,869 B2
• Time in Patent Office: Days
• US Class Current: 709/217
• CPC Class Codes: H04L 12/4135 using bit-wise arbitration
• CPC Class Codes: H04L 12/44 Star or tree networks

Abstract

When sending data, an ECU sends time lag information indicating a time lag that is a difference between time of generating time point at which the data is generated and time of sending start time point at which the ECU actually starts sending the data. When transferring the data, a relay apparatus adds time lag information indicating a time lag that is a difference between time of receiving start time point at which the relay apparatus starts receiving the data and time of transferring start time point at which the relay apparatus starts transferring the data, onto the time lag added on the received data. When receiving the data, an ECU determines for the received data the time of the generating time point that is earlier the time lag indicated by the time lag information of the received data than the time at which the ECU starts receiving the data.

Claims

1. A communication apparatus having a clock means, a communication means for sending and receiving data, and a possibility decision means for deciding whether it is possible or not to send data by the communication means, comprising:

a means for calculating a time lag between time at a generating time point that data is generated and time at a sending start time point that it is started to send the data whose sending is decided to be possible by the possibility decision means;

a means for adding time lag information indicating the obtained time lag onto the data;

a means for determining a receiving start time point based on time of the clock means; and

a determination means for determining a data generating time point based on the time lag information and the receiving start time point.

2. A communication apparatus according to claim 1, further comprising:

a means for acquiring time of a data sending start time point by the clock means, when it is decided by the possibility decision means that it is possible to send data by the communication means; and

a means for calculating a time lag between the time of the acquired data sending start time point and the time of the data generating time point, wherein

time lag information indicating the obtained time lag is added on the data that is already started to be sent.

3. A communication apparatus according to claim 1, further comprising:

a determination means for determining a sending start time point of sending data;

a calculating means for calculating a time lag between time of the determined sending start time point and the time of the generating time point;

a means for adding time lag information indicating the obtained time lag onto the data;

a means for deciding on the basis of time of the clock means whether the sending stat time point determined by the determination means has come or not; and

a means for trying to send, by the communication means, the data and the time lag information added on the data, when it is determined that the sending stat time point has come, wherein

when it is decided to be not-possible by the possibility decision means, a new sending start time point for starting to send secondarily is re-determined, the time lag is re-obtained, and data sending is re-tried.

4. A communication apparatus according to claim 1, further comprising:

a means for further transferring, when data with the added time lag information is received by the communication means, the data to another communication apparatus by the communication means;

a calculating means for calculating a time lag between the time of the generating time point of data determined by the determination means and time of a transferring start time point of data; and

a means for utilizing the time lag information indicated by the obtained time lag as the time lag information added on the transferred data.

8. A communication apparatus according to claim 2, further comprising:

a means for further transferring, when data with the added time lag information is received by the communication means, the data to another communication apparatus by the communication means;

a calculating means for calculating a time lag between the time of the generating time point of data determined by the determination means and time of a transferring start time point of data; and

a means for utilizing the time lag information indicated by the obtained time lag as the time lag information added on the transferred data.

9. A communication apparatus according to claim 3, further comprising:

a means for further transferring, when data with the added time lag information is received by the communication means, the data to another communication apparatus by the communication means;

a calculating means for calculating a time lag between the time of the generating time point of data determined by the determination means and time of a transferring start time point of data; and

a means for utilizing the time lag information indicated by the obtained time lag as the time lag information added on the transferred data.

5. A communication system comprising a plurality of communication apparatuses, each of which has a clock means, a communication means for sending and receiving data, and a possibility decision means for deciding whether it is possible or not to send data by the communication means, wherein

each communication apparatus comprises:

a means for calculating a time lag between time at a generating time point that data is generated and time at a sending start time point that it is started to send the data whose sending is decided to be possible by the possibility decision means;

a means for adding time lag information indicating the obtained time lag onto the data;

a means for determining a receiving start time point based on time of the clock means; and

a determination means for determining a generating time point of data based on the time lag information and the receiving start time point.

6. A method in which a communication apparatus having a clock means and a communication means for sending and receiving data decides whether it is possible or not to send data by the communication means and send the data in the case of deciding that it is possible to send the data by the communication means, wherein

the communication apparatus:

starts sending the data in response to deciding that it is possible to send the data by the communication means;

obtains time of a sending start time point of the data by the clock means;

calculates a time lag between the obtained time of the sending start time point and time of a generating time point at which the data is generated; and

adds time lag information indicating the calculated time lag onto the data having started to be sent, and then sends the data.

7. A method in which a communication apparatus having a clock means and a communication means for sending and receiving data decides whether it is possible or not to send data by the communication means and send the data in the case of deciding that it is possible to send the data by the communication means, wherein

the communication apparatus:

determines a sending start time point to send data;

calculates a time lag between time of the determined sending start time point and time of a generating time point at which the data is generated;

adds time lag information indicating the calculated time lag onto the data;

decides whether it reaches to the sending start time point or not;

tries to send the data and the time lag information added on the data by the communication means, when deciding it reaches to the sending start time point;

re-determines a new sending start time point for re-sending the data;

re-calculates the time lag; and

re-tries to send the data.