Abstract: A communication system includes: a communication device that receives data from a road-side apparatus and transmits the data as a plurality of data items in block units; and a processor that starts data processing whenever it is determined that a data item is received. The communication device includes a determination device that determines whether load reduction in the data processing is required, and a transmission device that transmits the plurality of data items as a series of data items such that it is not determined that a data item has been received when the load reduction is required. The processor includes an assembly device that divides the series of data items and assemblies the divided data.

Abstract: A communication system includes: a communication device that receives data from a road-side apparatus and transmits the data as a plurality of data items in block units; and a processor that starts data processing whenever it is determined that a data item is received. The communication device includes a determination device that determines whether load reduction in the data processing is required, and a transmission device that transmits the plurality of data items as a series of data items such that it is not determined that a data item has been received when the load reduction is required. The processor includes an assembly device that divides the series of data items and assemblies the divided data.

Abstract: An in-vehicle apparatus for performing a short range communication with a road side apparatus, which performs a hybrid communication including a broadcast communication and a point-to-point communication, is disclosed. The in-vehicle apparatus includes a communication unit and a retry count determination unit that determines whether a count of failure to establish the communication in an activation channel in the communication unit reaches a preset retry count. The in-vehicle apparatus re-selects a communication frequency when the retry count determination unit determines that the count of failure to establish the communication in the activation channel reaches the preset retry count.

Abstract: An in-vehicle apparatus for performing a short range communication with a road side apparatus, which performs a hybrid communication including a broadcast communication and a point-to-point communication, is disclosed. The in-vehicle apparatus includes a communication unit and a retry count determination unit that determines whether a count of failure to establish the communication in an activation channel in the communication unit reaches a preset retry count. The in-vehicle apparatus re-selects a communication frequency when the retry count determination unit determines that the count of failure to establish the communication in the activation channel reaches the preset retry count.