A Full Duplex Transceiver with Low Feedback Sampling Rate

Full duplex radio is one of the most promising techniques for the fifth-generation (5G) wireless networks. It usually includes a feedback loop to capture the nonlinear distortion of the transmitted signal for linearization of power amplifiers (PAs) and nonlinear self-interference (SI) cancellation. This paper presents an FD transceiver architecture consisting of the digital predistortion (DPD), radio frequency (RF)-tapping SI cancellation, and baseband (BB)-tapping SI cancellation. In particular, the issue of high sampling rate required in the feedback loop is addressed, and a BB-tapping method, which adopts a nonlinear modeling method with a low-rate aliasing transmitted signal, is proposed to significantly reduce the required feedback sampling rate. Numerical results verify that by using the proposed BB-tapping cancellation, a sampling rate of 25 MSPS is enough for the feedback loop in the scenario of a 100 MHz source signal.