Improvement of Interference Suppression Performance Using Antenna Selection of Mobile Terminal for Full-Duplex $4\times4$ MIMO System

This article presents an improvement of interference suppression between mobile terminals using the antenna selection method of a mobile terminal in a full-duplex MIMO system. In the system, a method of simultaneously transmitting and receiving a signal on the same frequency band in uplink and downlink between a base station and a mobile terminal has been studied. As a method of terminal-to-terminal interference suppression, a method of null beamforming for the first eigenvalue of the terminal-to-terminal channel by eigen-beamforming has been studied. The authors propose a method to realize further interference suppression by applying the antenna selection method to the mobile terminal when performing eigen-beamforming. The examination results of simulation using the ray tracing method and measurement in outdoor environment are reported assuming 4 × 4 MIMO in the frequency band of 12.9 GHz. From the evaluation results, the interference suppression effect by the antenna selection method is improved by about 3-5 dB compared with the conventional four element MIMO antenna.