Ofdm reception device, ofdm reception integrated circuit, ofdm reception method, and ofdm reception program

An integrated circuit for use in an OFDM reception apparatus for receiving an OFDM signal including a plurality of sub-carriers arranged in a symbol direction and a carrier direction, via a transmission channel, the circuit comprising:

• an orthogonal transform unit for performing orthogonal transform with respect to the received OFDM signal from a time domain into a frequency domain, to generate an OFDM signal in the frequency domain;
• a first transmission channel characteristic estimating unit for calculating a transmission channel characteristic value indicating phase and amplitude distortions in the OFDM signal generated by the orthogonal transform unit for each of the sub-carriers, the phase and amplitude distortions occurring during propagation through the transmission channel, and calculating an n-th (n is a natural number) differentiation of the transmission channel characteristic value for each of the sub-carriers;
• and
• an interference component removing unit for using the transmission channel characteristic value and the n-th differentiation calculated for each of the sub-carriers by the first transmission channel characteristic estimating unit, to remove an interference component be the sub-carriers adjacent to each other in the symbol direction or the carrier direction, from the OFDM signal generated by the orthogonal transform unit,
• wherein the first transmission channel characteristic estimating unit performs a filtering process in the symbol direction with respect to the transmission channel characteristic value calculated for each of the sub-carriers to perform oversampling at intervals each smaller than a one-symbol interval, and uses transmission channel characteristic values existing in intervals each smaller than a two-symbol interval of the transmission channel characteristic values obtained by the oversampling to calculate the n-th differentiations.

An OFDM reception method for receiving an OFDM signal including a plurality of sub-carriers arranged in a symbol direction and a carrier direction, via a transmission channel, the method comprising the steps of:

• performing orthogonal transform with respect to the received OFDM signal from a time domain into a frequency domain, to generate an OFDM signal in the frequency domain;
• calculating a transmission channel characteristic vale indicating phase and amplitude distortions in the OFDM signal in the frequency domain for each of the sub-carriers, the phase and amplitude distortions occurring during propagation through the transmission channel, and calculating an n-th (n is a natural number) differentiation of the transmission channel characteristic value for each of the sub-carriers;
• and
• using the calculated transmission channel characteristic value and n-th differentiation for each of the sub-carriers, to remove an interference component between the sub-carriers adjacent to each other in the symbol direction or the carrier direction, from the OFDM signal in the frequency domain,
• wherein in the calculating the transmission channel characteristic value and the n-th differentiation, a filtering process is performed in the symbol direction with respect to the transmission channel characteristic values of the sub-carriers to perform oversampling at intervals each smaller than a one-symbol interval, and transmission channel characteristic values existing in intervals each smaller than a two-symbol interval of the transmission channel characteristic values obtained by the oversampling are used to calculate the n-th differentiations.

A program executable by a computer that receives an OFDM signal including a plurality of sub-carriers arranged in a symbol direction and a carrier direction, via a transmission channel, the program causing the computer to execute the steps of:

• performing orthogonal transform with respect to the received OFDM signal from a time domain into a frequency domain, to generate an OFDM signal in the frequency domain;
• calculating a transmission channel characteristic value indicating phase and amplitude distortions in the OFDM signal in the frequency domain for each of the sub-carriers, the phase and amplitude distortions occurring during propagation through the transmission channel, and calculating an n-th (n is a natural number) differentiation of the transmission channel characteristic value for each of the sub-carriers;
• and
• using the calculated transmission channel characteristic value and n-th differentiation for each of the sub-carriers, to remove an interference component between the sub-carriers adjacent to each other in the symbol direction or the carrier direction, from the OFDM signal in the frequency domain,
• wherein in the calculating the transmission channel characteristic value and the n-th differentiation, a filtering process is performed in the symbol direction with respect to the transmission channel characteristic values of the sub-carriers to perform oversampling at intervals each smaller than a one-symbol interval, and transmission channel characteristic values existing in intervals each smaller than a two-symbol interval of the transmission channel characteristic values obtained by the oversampling are used to calculate the n-th differentiations.