Receiving device, receiving method, and program

A receiving method comprising the steps of:

• extracting a pilot signal from a received orthogonal frequency division multiplexing (OFDM) signal;
• estimating a characteristic of a channel of the OFDM signal for the pilot signal and interpolating a channel characteristic in a time direction to thereby obtain a channel characteristic of every predetermined number of subcarriers;
• carrying out filtering of the channel characteristic of every predetermined number of subcarriers by an interpolation filter having a first band for interpolating a channel characteristic in a frequency direction to thereby obtain a first all-subcarrier channel characteristic, and carrying out filtering of the channel characteristic of every predetermined number of subcarriers by an interpolation filter having a second band wider than the first band for interpolating a channel characteristic in the frequency direction to thereby obtain a second all-subcarrier channel characteristic;
• correcting distortion of the OFDM signal by using the first all-subcarrier channel characteristic and correcting distortion of the OFDM signal by using the second all-subcarrier channel characteristic;
• calculating quality of each of the OFDM signals whose distortion has been corrected;
• and
• determining whether or not a channel environment is a single path environment or a near delay path environment in which all paths are allowed to be included in a passband of an interpolation filter having the first band, based on quality of a first distortion-corrected signal that is the OFDM signal whose distortion has been corrected by using the first all-subcarrier channel characteristic and quality of a second distortion-corrected signal that is the OFDM signal whose distortion has been corrected by using the second all-subcarrier channel characteristic.

A program causing a computer to execute processing, the processing comprising the steps of:

• extracting a pilot signal from a received OFDM signal;
• estimating a characteristic of a channel of the OFDM signal for the pilot signal and interpolating a channel characteristic in a time direction to thereby obtain a channel characteristic of every predetermined number of subcarriers;
• carrying out filtering of the channel characteristic of every predetermined number of subcarriers by an interpolation filter having a first band for interpolating a channel characteristic in a frequency direction to thereby obtain a first all-subcarrier channel characteristic, and carrying out filtering of the channel characteristic of every predetermined number of subcarriers by an interpolation filter having a second band wider than the first band for interpolating a channel characteristic in the frequency direction to thereby obtain a second all-subcarrier channel characteristic;
• correcting distortion of the OFDM signal by using the first all-subcarrier channel characteristic and correcting distortion of the OFDM signal by using the second all-subcarrier channel characteristic;
• calculating quality of each of the OFDM signals whose distortion has been corrected;
• and
• determining whether or not a channel environment is a single path environment or a near delay path environment in which all paths are allowed to be included in a passband of an interpolation filter having the first band, based on quality of a first distortion-corrected signal that is the OFDM signal whose distortion has been corrected by using the first all-subcarrier channel characteristic and quality of a second distortion-corrected signal that is the OFDM signal whose distortion has been corrected by using the second all-subcarrier channel characteristic.

A receiving device comprising:

• pilot signal extraction means for extracting a pilot signal from a received orthogonal frequency division multiplexing (OFDM) signal;
• estimation means for estimating a characteristic of a channel of the OFDM signal for the pilot signal and interpolating a channel characteristic in a time direction to thereby obtain a channel characteristic of every predetermined number of subcarriers;
• interpolation means for carrying out filtering of the channel characteristic of every predetermined number of subcarriers by an interpolation filter having a first band for interpolating a channel characteristic in a frequency direction to thereby obtain a first all-subcarrier channel characteristic, and carrying out filtering of the channel characteristic of every predetermined number of subcarriers by an interpolation filter having a second band wider than the first band for interpolating a channel characteristic in the frequency direction to thereby obtain a second all-subcarrier channel characteristic;
• distortion correction means for correcting distortion of the OFDM signal by using the first all-subcarrier channel characteristic and correcting distortion of the OFDM signal by using the second all-subcarrier channel characteristic;
• calculation means for calculating quality of each of the OFDM signals whose distortion has been corrected;
• and
• determination means for determining whether or not a channel environment is a single path environment or a near delay path environment in which all paths are allowed to be included in a passband of an interpolation filter having the first band, based on quality of a first distortion-corrected signal that is the OFDM signal whose distortion has been corrected by using the first all-subcarrier channel characteristic and quality of a second distortion-corrected signal that is the OFDM signal whose distortion has been corrected by using the second all-subcarrier channel characteristic.