Abstract: An object of the present invention is to provide a sending apparatus, sending method and a communication system with utilizing the sending apparatus that can improve efficiency of data sending operation and can reduce a duty for data communication. Each sending apparatus classifies data stored on a storage into groups “X”, “Y” and “Z”, fractionates a clump of data, classified into each of the groups “X”, “Y” and “Z”, by a number of fractions based on a sending completion allowable time for the classified data, and sends the fractionated data in multi cycles at every sending interval, without sending and receiving the data stored on the storage all at once. Each sending apparatus selects any one piece of data generated from fractionated clump of data for each of the groups “X”, “Y” and “Z”, and then sends the selected piece of data at every sending interval.

Abstract: It is provided about a communication system adapting for car, communication apparatus adapting for car and a communication method adapting for car that can perform data transmission under extensive range from a low speed communication to high speed communication, without generating data delay, data dropout and the like, caused by the data sending collision. A gateway and an ECU are connected to each other, in a one-to-one manner, via a communication line different from another communication line for another connection. When receiving a message, the gateway and the ECU reply a receipt response. When having a message to be sent toward the destination for replying at this replying time, the gateway and the ECU sends the receipt response onto which this message to be sent is added. When a message sending collision is generated, the gateway preferentially performs a message re-sending operation.

Abstract: GW apparatuses send messages including data being sent from ECUs to a distribution apparatus without sending to an ECU. The distribution apparatus stores the messages on a database, and sends the messages to an ECU, and an ECU. In a case, the distribution apparatus sends the messages in a message sending order and the GW apparatuses relays the messages being sent from the distribution apparatus to the ECUs. The message sending order may be an order in which the distribution apparatus receives the messages an ascending (descending) order of values corresponding to message IDs applied to the messages, or an ascending order of message received time of the messages.