Data transmission method and system therefor
First Claim
1. In a data transmission system for a vehicle, including a plurality of control systems installed on said vehicle, and a network bus connecting said plurality of control systems with each other for circulating a transmission right through said plurality of control systems to thereby perform transmission of a message between said plurality of control systems,the improvement wherein each of said plurality of control systems comprises:
- a transmitter-receiver for transmitting data to or receiving data from the rest of said plurality of control systems via said network bus;
collision-detecting means for detecting a collision of data transmitted from said transmitter-receiver with data transmitted from any of the rest of said plurality of control systems;
mediating means for performing mediation on said data transmitted from said transmitter-receiver and having been detected to be collided with said data transmitted from any of the rest of said plurality of control systems to direct said transmitter-receiver to continue data transmission or to stop said data transmission, for the purpose of avoiding said collision of data,monitor means for monitoring said transmission right;
control means for causing said transmitter-receiver to start transmitting data when said monitor means detects that said transmission right is not generated or lost from said system, and for causing said transmitter-receiver to obtain said transmission right and to continue transmitting said data when said collision-detecting means does not detect a collision of said data with data transmitted from the rest of said plurality of control systems, or when said mediating means directs said transmitter-receiver to continue data transmission;
wherein said mediating means includes means for comparing said data transmitted from said transmitter-receiver with said data received via said network bus from the rest of said plurality of control systems, bit by bit, based on a logic considering one of logical levels of transmission data as dominant, and another of said logical levels of said transmission data as recessive, and for directing said transmitter-receiver to stop said data transmission when said data transmitted from said transmitter-receiver and said data received from said network bus are different from each other; and
transfer means for transferring said transmission right to a subsequent control system in a predetermined manner, when said control means controls said transmitter-receiver to continue said data transmission until said data transmission is completed;
said transfer means transferring said transmission right to said subsequent control unit by increasing an address representative of said each of said plurality of control systems incorporating said transfer means by a predetermined number.
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Accused Products
Abstract
A data transmission system for a vehicle includes a plurality of control systems installed on the vehicle, and a network bus connecting the plurality of control systems with each other for circulating a transmission right through the plurality of control systems to thereby perform transmission of a message between the plurality of control systems. According to a first aspect, each of the control systems starts transmitting data when it is detected that the transmission right is not generated or lost from the system, and continues transmitting the data when no collision of data transmitted from the present control system with data transmitted from the rest of the plurality of control systems, or when by mediation for avoiding the collision is detected, it is determined to continue data transmission. According to another aspect, the maximum number of times of retransmission to be permitted is determined according to a type of failure in transmission identified, and the retransmission is performed so long as the number times of retransmission of the data does not exceed the maximum number of times of retransmission to be permitted. According to a still another aspect, the message comprises a first response field for receiving a first acknowledging response output from a control system having received the transmission right, and a second response field for receiving a second acknowledging response output from a control system having received data.
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Citations
1 Claim
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1. In a data transmission system for a vehicle, including a plurality of control systems installed on said vehicle, and a network bus connecting said plurality of control systems with each other for circulating a transmission right through said plurality of control systems to thereby perform transmission of a message between said plurality of control systems,
the improvement wherein each of said plurality of control systems comprises: -
a transmitter-receiver for transmitting data to or receiving data from the rest of said plurality of control systems via said network bus; collision-detecting means for detecting a collision of data transmitted from said transmitter-receiver with data transmitted from any of the rest of said plurality of control systems; mediating means for performing mediation on said data transmitted from said transmitter-receiver and having been detected to be collided with said data transmitted from any of the rest of said plurality of control systems to direct said transmitter-receiver to continue data transmission or to stop said data transmission, for the purpose of avoiding said collision of data, monitor means for monitoring said transmission right; control means for causing said transmitter-receiver to start transmitting data when said monitor means detects that said transmission right is not generated or lost from said system, and for causing said transmitter-receiver to obtain said transmission right and to continue transmitting said data when said collision-detecting means does not detect a collision of said data with data transmitted from the rest of said plurality of control systems, or when said mediating means directs said transmitter-receiver to continue data transmission; wherein said mediating means includes means for comparing said data transmitted from said transmitter-receiver with said data received via said network bus from the rest of said plurality of control systems, bit by bit, based on a logic considering one of logical levels of transmission data as dominant, and another of said logical levels of said transmission data as recessive, and for directing said transmitter-receiver to stop said data transmission when said data transmitted from said transmitter-receiver and said data received from said network bus are different from each other; and transfer means for transferring said transmission right to a subsequent control system in a predetermined manner, when said control means controls said transmitter-receiver to continue said data transmission until said data transmission is completed; said transfer means transferring said transmission right to said subsequent control unit by increasing an address representative of said each of said plurality of control systems incorporating said transfer means by a predetermined number.
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Specification