A communication system for pulse based communication using a sequence acquisition system using the correlation method in UWB communications which generates a pulse detection signal differing in phase by exactly a predetermined period (τ) from the transmission information of a pulse signal of a predetermined period at the transmission side and reception side, uses the pulse detection signal to establish synchronization at the reception side, then generates transmission information at the reception side by making its phase different by exactly a predetermined time from the synchronized pulse detection signal so as to establish synchronization between the reception signal and the transmission information, whereby it is possible to enable synchronization acquisition and shorten the synchronization acquisition time without complicating the hardware and even without the presence of information in the transmission signal.