The invention relates to an apparatus and a method for estimating a fading
frequency of incoming received waves in a receiving station of a radio
communication system or radio transmission system. An object of the
invention is to estimate a fading frequency efficiently and accurately
without substantially complexing the configuration of the system. To this
end, the invention provides an apparatus for estimating a fading
frequency from a pilot signal in a reception signal, which includes a
calculation unit for calculating a magnitude of a complex product of two
symbols that are received at different instants, and an estimation unit
for estimating a fading frequency according to the calculated magnitude
of the complex product.