Self-interference cancelation through advanced sampling

Self-interference is the main obstacle to overcome in order to enable a wireless device to simultaneously transmit and receive in overlapped frequency bands. There is much interest to suppress this interference employing compact and efficient cancelers, which operate in the digital domain, extending this way the benefits of in-band full-duplex to innumerable applications. However, this is not an easy task since the desired signal results hidden in quantization noise during analog-to-digital conversion because of the tremendous power asymmetry between the self-interference and desired signal. This paper proposes an alternative receiver structure in which the received signal is sampled at the zero-amplitude instants of the interference. Our analysis demonstrates that the resulting sampling process preserves the information conveyed in the desired signal and that demodulation is possible. The performance of this novel full-duplex receiver is evaluated using simulations, proving that this sampling strategy enables all digital self-interference cancelation.