Method of transmitting ofdm signal and transmitter and receiver thereof

An OFDM transmitter transmitting OFDM signals comprising;

• an allocation unit configured to allocate a first pilot signal and a first data signal respectively to at least one first pilot subcarrier and first data subcarriers within a subcarrier group that is identical among the transmitters, and to allocate a second pilot signal and a second data signal respectively to at least one second pilot subcarrier and the second data subcarriers outside the subcarrier group;
• a multiplier configured to multiply the first pilot signal and the first data signal by a complex number set for the subcarrier group;
• a modulator configure to generate an OFDM signal by performing OFDM modulation on the first pilot signal and the first data signal multiplied by the complex number and the second pilot signal and the second data signal;
• and
• a transmission unit configured to transmit the generated OFDM signal.

An OFDM receiver receiving an OFDM signal, comprising;

• an OFDM demodulator configured to subject the OFDM signal to OFDM demodulation to divide the received OFDM signal into a plurality of signals corresponding to respective subcarriers;
• a separator configured to separate from a signal of each of the subcarriers a first pilot signal and a first data signal allocated respectively to at least one first pilot subcarrier and first data subcarriers included in at least one subcarrier group;
• an estimation unit configured to estimate channel response using the first pilot signal separated by the separator;
• an equalizer configured to equalize the separated first data signal in accordance with the channel response estimated by the estimation unit;
• and
• a data demodulator configured to demodulate the first data signal equalized by the equalizer.

An OFDM receiver receiving OFDM signals, comprising;

• an OFDM demodulator configured to subject an OFDM signal to OFDM demodulation to divide a received OFDM signal into a plurality of signals corresponding to respective subcarriers;
• a separator configured to separate from a signal of each of the subcarriers a first pilot signal allocated to at least one first pilot subcarrier included in at least one subcarrier group, the first data signal allocated to first data subcarriers included in the subcarrier group, a second pilot signal allocated to the second pilot subcarriers outside the subcarrier group, and a second data signal allocated to the second data subcarriers outside the subcarrier group;
• a first estimation unit configured to estimate a first channel response using the separated first pilot signal;
• a first equalizer configured to equalize the separated first data signal in accordance with the estimated first channel response;
• a descrambler configured to descramble the separated second pilot signal and the second data signal;
• a second estimation unit configured to estimate a second channel response using the descrambled second pilot signal;
• a second equalizer configured to equalize the descrambled second data signal in accordance with the estimated second channel response;
• and
• a data demodulator configured to demodulate the equalized first data signal and the equalized second data signal.