A receiving apparatus for a digital mobile communication system comprises an adaptive filter for filtering an input signal. A step-size parameter chosen for the adaption of filter coefficients of the adaptive filter is computed from a variation of the filter coefficients used by the adaptive filter. This facilitates an indirect measure for the channel variation so that a good reception quality over a wide range of user velocities may be enabled in contrast to a system design based on a compromise step-size parameter being optimum for one velocity only.