Breaking the Barrier of Transmission Noise in Full-Duplex Radio

The key technical challenge in making a full-duplex radio is self-interference cancelation (SIC). The self-interference received by a full-duplex radio has two major components: one corresponds to an information-carrying waveform meant for a remote radio and the other corresponds to the noise generated from the transmit chain of the full-duplex radio. The transmission signal-to-noise ratio (SNR) of a typical radio is only about 30dB. This severely limits the performance of any SIC methods which ignore the transmission noise. None of the previously known digital or hybrid methods for SIC has any built-in mechanism to handle the transmission noise. In this paper, we present a new analog-digital hybrid method whose performance is no longer limited by the transmission noise. This method also involves a blind system identification and equalization algorithm for finding the optimal parameters of the cancelation filter.