Apparatus removing self-interference in environment supporting FDR method

A communication apparatus for performing self-interference cancellation (SIC) in an environment supporting a full duplex radio (FDR) scheme, the communication apparatus comprising:

• a transmitter configured to transmit a reference signal (RS) with a first transmission power, the first transmission power being different from a second transmission power used for transmission of a previous RS;
• an analog self-interference (SI) canceller circuit;
• an SI signal generator circuit configured to:
• generate a first SI signal by applying a first attenuation coefficient to transmit the first SI signal to the analog SI canceller circuit from a first delay circuit connected between radio frequency (RF) transmission and reception chains of the communication apparatus, and
• generate a second SI signal by applying a second attenuation coefficient to transmit the second SI signal to the analog SI canceller circuit from a second delay circuit connected between the RF transmission and reception chains of the communication apparatus,
• wherein the first attenuation coefficient is determined based on the first transmission power of the RS,
• wherein the second attenuation coefficient is determined based on the second transmission power used for transmission of the previous RS, and
• wherein the analog SI canceller circuit is configured to:
• perform a first analog SIC by subtracting the first SI signal from an SI signal received at the RF reception chain from a reception antenna, and
• perform a second analog SIC by subtracting the second SI signal from the SI signal;
• and
• a processor configured to determine whether the first analog SIC is successful based on a residual SI signal remaining after performing the first analog SIC and determine whether the second analog SIC is successful based on a residual SI signal remaining after performing the second analog SIC.