Central unit, sub unit and method for communicating

A central unit for communicating with at least one side unit comprises a transmission unit for transmitting a sequence of multi-frames, and a processor for generating the series of multi-frames. A multi-frame of the sequence of multi-frame comprises a control frame and useful frames, wherein the control frame comprises sleep mode information for the at least one slave unit, wherein the sleep mode information indicating a time period in which the to be at least one slave unit in a sleep mode, wherein the time period is greater than or equal to the is duration of the at least one Nutzrahmens of the multiframe. Thus slave units can be deterministic and arbitrarily displaced long in a sleep mode to provide the lowest possible power consumption in the slave unit.