There is provided a multi-carrier transmission system which includes: an
encoder for converting a data sequence into encoded symbols corresponding
to respective sub-carriers; a first shifter for rearranging the encoded
symbols to define a guard interval length; an inverse fast Fourier
transform (IFFT) unit for inverse fast Fourier transforming the
rearranged encoded symbols; a second shifter for processing the
transformed symbols to effect a frequency shift to compensate for a
frequency shift effected by the IFFT unit; and a guard interval inserter
for interleaving symbol replicas with the processed symbols according to
the guard interval length. The data transmission system of the present
invention performs sub-carrier relocation function and guard interval
insertion function using relatively simple elements in order to reduce
the data processing time. As a result, the transmission efficiency of the
entire communication system is enhanced.