Self-Interference Cancellation in MIMO Full-Duplex Transceivers

Resumen

The transceiver nonlinearities have recently been shown to limit the performance of in-band FD (Full-Duplex) devices. In this article, detailed modeling and mitigation algorithms of more critical of these nonlinearities, in order to obtain better SI (Self-Interference) cancellation performance are presented. In the transmitter side, we applied DPD (Digital Predistortion) to both, transmit and cancellation chains in order to obtain output signals free from nonlinearities of RF components, and crosstalk, which allow better RF cancellation. In the receiver side, the nonlinearities of RF components are modeled and the residual SI that will experiment these nonlinearities is removed by digital cancellation. Our proposed method, ''DPD cancellation'', provides one of the simple signal models that takes into account more of RF impairments, such as PA (Power Amplifier) nonlinearity, LNA (Low Noise Amplifier), DAC (Digital to Analog Converter) nonlinearities, IQ imbalance at both, transmitter and receiver, and nonlinear crosstalk between the transmitter chains in Multiple Input Multiple Output Full-Duplex systems (MIMO-FD). In this paper the effect of the phase noise was considered in the hardware structure by using the same local oscillator for transmitter, cancellation and receiver chains. Also, the simulation results show that, our method, DPD cancellation, provides better SINR (Signal to Interference plus Noise Ratio) at the input of the detector, when compared to others methods in literature. In this way, it can be considered as one of the promising methods for the practical implementation of FD transmission in the future wireless systems.