Disclosed herein is a communication system wherein, non-periodical communications of data are carried out between an information transmitting terminal and one or more information receiving terminals, the information transmitting terminal periodically broadcasts network control information to the information receiving terminals, each of the information receiving terminals receives the network control information from the information transmitting terminal at a rate determined in advance, each of the information receiving terminals receives the network control information from the information transmitting terminal in a fixed-length information acquisition period; and at least some specific ones of the information receiving terminals each arbitrarily shift the starting point of the information acquisition period of the specific information receiving terminal.