A method, apparatus and computer program product that in a mobile data communications system having at least one base station, at least one beacon and at least one mobile device, enables the mobile devices to conserve power. A wireless communication subsystem in each mobile device communicates with the base station. A beacon either signals the presence of a main base station or the need for the mobile device to attempt to associate or communicate with the base station. A beacon detection circuit in a mobile device activates the wireless communication subsystem in the mobile device when the beacon is received by the beacon detection circuit, which may be a passive circuit using no power, or a very low power receiver.