Communication apparatus, communication system, and computer program

A communication apparatus that receives data that includes identification information, comprising:

• a comparison unit that compares a plurality of pieces of data that include the same identification information if they are received within a preset time range;
• a range change unit that changes the time range based on a time point at which data that includes the same identification information was received;
• and
• a selection unit that selects the data included in the largest data group if it is determined, as a result of the comparison unit comparing the plurality of pieces of data, that there are one or more data groups each consisting of data having the same content, and the number of largest data groups with the largest number of pieces of data among the one or more data groups is one,
• wherein, if it is determined, as a result of the comparison unit comparing the plurality of pieces of data, that there is no such data group or the number of largest data groups is greater than one, contents of the plurality of pieces of data are ignored.