Interference cancellation circuit and operating method thereof

An interference cancellation circuit comprising:

• a relative delay control circuit configured to receive a first transmission signal of a first frequency and a second transmission signal of a second frequency different from the first frequency, wherein the relative delay control circuit includes a first delay buffer that is configured to delay the second transmission signal by a relative delay, and a second delay buffer that is configured to delay, by an interference sampling period, the second transmission signal delayed by the relative delay;
• a delay reference generation circuit configured to receive, from the relative delay control circuit, the first transmission signal, the second transmission signal delayed through the first delay buffer, and the second transmission signal delayed through the second delay buffer, to generate a first reference signal based on the first transmission signal and the second transmission signal delayed through the first delay buffer, and to generate a second reference signal based on the first transmission signal and the second transmission signal delayed through the second delay buffer;
• a weight control circuit configured to update a weight vector;
• a relative delay estimation circuit configured to estimate a relative delay based on the first reference signal and the second reference signal;
• and
• an adaptive filter configured to generate an interference model signal based on the weight vector and the first reference signal and filter the interference model signal from a received signal.

A method for interference cancellation, the method comprising:

• generating first, second, and third reference signals;
• calculating a partial differential value for a relative delay of the first reference signal;
• calculating a partial differential value for a relative delay of a weight vector;
• and
• estimating the relative delay of the first reference signal by using the partial differential value for the relative delay of the weight vector and the partial differential value for the relative delay of the first reference signal, wherein
• the first reference signal corresponds to a signal that is obtained by modelling an intermodulation interference based on a first transmission signal without a delay and a second transmission signal with a relative delay of the second transmission signal,
• the second reference signal corresponds to a signal that is obtained by modelling an intermodulation interference based on the first transmission signal and the second transmission signal without a delay, and
• the third reference signal corresponds to a signal that is obtained by modelling an intermodulation interference based on the first transmission signal and a third transmission signal with a delay of an interference sampling period.