To avoid prolongation of an average synchronism detection time, even when a synchronization signal is not transmitted in partial transmission bands.
A communication system includes: a transmission means and a reception means, the transmission means including a synchronization signal generating means for generating a synchronization signal for establishing synchronism and a transmission-side radio means for transmitting data and the synchronization signal, and the reception means including a synchronism detecting means for detecting the synchronization signal to establish synchronism. The transmission means further includes a sub-band selecting means for selecting as a frequency band to insert the synchronization signal therein a frequency band capable of inserting the synchronization signal into a frequency in which the synchronism detecting means can detect the synchronization signal fast, and a selective synchronization signal inserting means for inserting the synchronization signal into the frequency band selected by the sub-band selecting means and defining at least any one of other frequency bands as a subordinate sub-band not to insert the synchronization signal therein, and the transmission-side radio means transmits the synchronization signal in the frequency band into which the synchronization signal has been inserted.
Ishibashi Masayuki
Masaaki Ogata