Joint Transmission Null Beamforming for MIMO Full-Duplex Wireless Communication System

Cancellation of self interference (SI) is an important tech-nology in order for wireless communication system devices to perform full -duplex communication. In this paper, we propose a novel self-interference cancellation using null beamforming to be applied entire IEEE 802.11 frame including the legacy part for full-duplex wireless communication on Co-operative MIMO (Multiple Input Multiple Output). We evaluate the SI cancellation amount by the proposed method using a field programmable gate array (FPGA) and software defined radio (SDR), and show the exper-imental results. In the experiment, it is confirmed that the amount of SI cancellation by the proposed method was at least 18 dB. The SI cancellation amount can be further potentiated with more accurate CSI (channel state information) by increasing the transmission power. It is shown that SI can be suppressed whole frame which includes legacy preamble part. The pro-posed method can be applied to next generation wireless communication standards as well.