A method of manufacturing a prefabricated precast riser module, where the required forms that are used in casting the modules are reusable and need not to be transported to the construction site. In a modulator, a pre-equalization of the signals is performed in which the transmission properties of all the radio channels and the different codes of all the radio channels are taken into account. Use of the first cylinder group, and deactivation of the second cylinder group during partial loads increases engine efficiency and fuel economy. An objective function is employed, which is based upon the parameters of the underlying functions.