  Channel estimation is one of the most important parts in current mobile
communication systems. Among the huge contributions in channel estimation
studies, the discrete Fourier transform (DFT)-based channel estimation has
attracted lots of interests since it can not only be easily implemented but
also have acceptable performance in practical systems. In this paper, we
propose an improved DFT-based channel estimation scheme that tries to clean the
reference signals in the time domain before being used for interpolation using
the estimated noise variance from reference signals on multiple orthogonal
frequency division multiplexing (OFDM) symbols via the property of DFT. The
proposed channel estimation scheme does not need any priori channel
information. We validate the proposed channel estimation scheme in various
channel models via simulations and comparison with conventional channel
estimation schemes.
