Patent ID: 7133458

Claim:
A receiving apparatus for multiplex communication based on multi-carrier modulation where subcarriers of a plurality of channels are cyclically arranged, comprising: receiving means for receiving a group of signals; a signal component demultiplexing apparatus having a plurality of branching circuits connected in stages and hierarchically by a branching method, each of the plurality of branching circuits provided with: symbol delaying means for delaying an input group of signals by N/2 (m+1) symbols; phase offset adjusting means for shifting a phase of the input group of signals −π(k/2 m ) radians with a reference of 0 Hz; adding means for adding an output signal of the symbol delaying means and an output signal of the phase offset adjusting means to calculate one symbol string alternately positioned on a frequency axis in a multiplexed signal input to a signal selecting and outputting means; and subtracting means for subtracting the output signal of the phase offset adjusting means from the output signal of the symbol delaying means to calculate an other symbol string alternately positioned on the frequency axis in the multiplexed signal input to the signal selecting and outputting means, wherein m is a parameter indicating a position of a stage of each of the branching circuits; N is a number of symbols existing within one modulation time; and k is a parameter indicating that a group of signals having a frequency offset of a subcarrier is input with the reference of 0 Hz; signal selecting means for selecting and outputting one group of symbols of predetermined subcarriers from among the symbol strings demultiplexed at the signal component demultiplexing apparatus; frequency offset compensating means for compensating for a frequency offset of the one group of symbols selected and output by the signal selecting means; two orthogonal transforming means for orthogonally transforming output signals of the frequency offset compensating means; and decoding means for decoding the orthogonally transformed signal.