| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a communication device, a communication system, and a communication method that can set transmission speed of transmission data and tolerance to a disturbing wave depending on a propagation environment, and in addition that can reduce cost having a simple structure. <P>SOLUTION: In a master terminal A1, a diffusion unit 11c selects spread codes from a code storage unit 11h in the ascending or descending order of code length, and generates a keep-alive confirmation request diffused with the selected spread code; a transmission unit 11d broadcasts the keep-alive confirmation request to a slave terminal A2. After receiving one or multiple acknowledgements returned from the slave terminal A2, the master terminal A1 selects a spread code having the same code length as the shortest code length among the code lengths of spread codes used for respective diffusion for one or multiple acknowledgements transmitted by the slave terminal A2 for a spread code to be used when transmission data to the slave terminal A2, which is a transmission source of the acknowledgements, is diffused. <P>COPYRIGHT: (C)2012,JPO&INPIT |
