Interference cancellation device, control circuit, storage medium, and interference center frequency estimation method

A control circuit to control an interference cancellation device, the control circuit causing the interference cancellation device to:

• extract a data symbol portion from a received signal having null symbols inserted into data symbols, and output a data symbol signal;
• extract a null symbol portion from the received signal, and output a null symbol signal;
• calculate a data symbol power estimated value representing electric power of the data symbol signal;
• calculate a null symbol power estimated value representing electric power of the null symbol signal;
• calculate a null symbol spectrum from the null symbol signal;
• calculate an interference center frequency estimated value of an interference included in the received signal, using the data symbol signal, the data symbol power estimated value, the null symbol power estimated value, and the null symbol spectrum, wherein the control circuit causes the interference cancellation device to, in calculating the interference center frequency estimated value, compare the null symbol spectrum with a predefined threshold, and determine that a half of total bandwidth of frequency bands each having electric power in excess of the threshold is an interference bandwidth of the interference, and to, in calculation of the interference bandwidth, eliminate an effect of an image for the interference.

A non-transitory storage medium storing a program to control an interference cancellation device,

• the program causing the interference cancellation device to:
• extract a data symbol portion from a received signal including a null symbol inserted into data symbols, and output a data symbol signal;
• extract a null symbol portion from the received signal, and output a null symbol signal;
• calculate a data symbol power estimated value representing electric power of the data symbol signal;
• calculate a null symbol power estimated value representing electric power of the null symbol signal;
• calculate a null symbol spectrum from the null symbol signal;
• calculate an interference center frequency estimated value of an interference included in the received signal, using the data symbol signal, the data symbol power estimated value, the null symbol power estimated value, and the null symbol spectrum, wherein the program causes the interference cancellation device to, in calculating the interference center frequency estimated value, compare the null symbol spectrum with a predefined threshold, and determine that a half of total bandwidth of frequency bands each having electric power in excess of the threshold is an interference bandwidth of the interference, and to, in calculation of the interference bandwidth, eliminate an effect of an image for the interference.

An interference center frequency estimation method comprising:

• extracting a data symbol portion from a received signal having null symbols inserted into data symbols, and outputting a data symbol signal;
• extracting a null symbol portion from the received signal, and outputting a null symbol signal;
• calculating a data symbol power estimated value representing electric power of the data symbol signal;
• calculating a null symbol power estimated value representing electric power of the null symbol signal;
• a fifth step in which a null symbol spectrum calculation unit calculates calculating a null symbol spectrum from the null symbol signal;
• calculating an interference center frequency estimated value of an interference included in the received signal, using the data symbol signal, the data symbol power estimated value, the null symbol power estimated value, and the null symbol spectrum, wherein, when the interference center frequency estimated value is calculated, the null symbol spectrum is compared with a predefined threshold, and a half of total bandwidth of frequency bands each having electric power in excess of the threshold is determined to be an interference bandwidth of the interference, and, in calculation of the interference bandwidth, an effect of an image for the interference is eliminated.