Digital controlled co-channel feedback interference cancellation system with broadband cancellation

In this work, a digital controlled co-channel feedback interference cancellation system is proposed to reduce the feedback interference signal in the wireless repeater system. Frequency hopping spread spectrum pilot tone is adopted for the adaptive group delay detection of the feedback path. Amplitude, phase, and group delay of the feedback path are automatically detected and controlled through the comparison algorithm using DSP. Adaptive feedback cancellation of over 30 dB is achieved with the proposed system for the signal bandwidth of 20 MHz in Korean RFID band.